Plaque Psoriasis

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Practice Essentials

Psoriasis, which manifests most often as plaque psoriasis, is a chronic, relapsing, inflammatory skin disorder with a strong genetic basis. Plaque psoriasis (see the image below) is rarely life threatening, but it often is intractable to treatment.



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Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

See Psoriasis: Manifestations, Management Options, and Mimics, a Critical Images slideshow, to help recognize the major psoriasis subtypes and distinguish them from other skin lesions.

Signs and symptoms

Psoriatic plaques are characterized as follows:

Other manifestations of plaque psoriasis include the following:

Manifestations of the psoriatic arthritis include the following:

Children

In children with plaque psoriasis, plaques are not as thick, and the lesions are less scaly. Psoriasis often appears in the diaper region in infancy and in flexural areas in children. The disease more commonly affects the face in children than it does in adults.

Diagnosis

Laboratory studies

The diagnosis of psoriasis is almost always made on the basis of clinical findings. Laboratory investigations are rarely indicated.

Skin biopsy

Skin biopsy can confirm the diagnosis of plaque psoriasis. This procedure, however, is usually reserved for the evaluation of atypical cases or for excluding other conditions in cases of diagnostic uncertainty.

Histology

Histologic epidermal findings include the following:

Histologic dermal findings include the following:

Management

Topical therapy

Topical agents used (often concurrently) to treat plaque psoriasis include the following:

Phototherapy

The two main forms of phototherapy are as follows:

Systemic therapy

Systemic treatment is initiated only after topical treatments and phototherapy have proved unsuccessful. Systemic therapy should also be considered for patients with very active psoriatic arthritis, as well as for patients whose disease is physically, psychologically, socially, or economically disabling.[1, 2, 3, 4]

Biologic therapy

Biologic therapies provide selective, systemic, immunologically directed interventions, including the following, at key steps in the pathogenesis of plaque psoriasis[5] :

Background

Psoriasis is a common, chronic, relapsing, inflammatory skin disorder with a strong genetic basis. The plaque type of psoriasis is the most common, although several other distinctive clinical variants of psoriasis are recognized (eg, Guttate Psoriasis; Psoriasis, Nails; Psoriasis, Pustular; Psoriatric Arthritis).

Plaque psoriasis is most typically characterized by circular-to-oval red plaques distributed over extensor body surfaces and the scalp. The plaques usually exhibit scaling as a result of epidermal hyperproliferation and dermal inflammation. The extent and duration of plaque psoriasis is highly variable from patient to patient. Acute flares or relapses of plaque psoriasis may also evolve into more severe disease, such as pustular or erythrodermic psoriasis.

Up to 10-20% of patients with plaque psoriasis also experience psoriatic arthritis. A population-based study by Wilson et al that spanned more than 30 years reported that less than 10% of psoriasis patients develop clinically recognized psoriatic arthritis. The clinical features that were associated with an increased chance of leading to psoriatic arthritis were reported as being scalp lesions, nail dystrophy, and intergluteal or perianal psoriasis.[10]

For more information, see Psoriasis.

Pathophysiology

The pathophysiology of psoriasis must be understood in terms of the prominent pathologies occurring in both major components of the skin—the epidermis and the dermis.

Psoriasis is fundamentally an inflammatory skin condition with reactive abnormal epidermal differentiation and hyperproliferation. Current research suggests that the inflammatory mechanisms are immune based and most likely initiated and maintained primarily by T cells in the dermis.[11]

In this model, antigen-presenting cells in the skin, such as Langerhans cells, are believed to migrate from the skin to regional lymph nodes, where they interact with T cells. Presentation of an as yet unidentified antigen to the T cells, as well as a number of co-stimulatory signals, triggers an immune response, leading to T-cell activation and the release of cytokines.

Co-stimulatory signals are initiated via the interaction of adhesion molecules on the antigen-presenting cells, such as lymphocyte function–associated antigen (LFA)–3 and intercellular adhesion molecule-1, with their respective receptors CD2 and LFA-1 on T cells. These T cells are released into the circulation and traffic back into the skin.

Reactivation of T cells in the dermis and epidermis and the local effects of cytokines such as tumor necrosis factor lead to the inflammation, cell-mediated immune responses, and epidermal hyperproliferation observed in persons with psoriasis.

An interleukin (IL)-12–related cytokine, IL-23, is involved in the establishment of chronic inflammation and in the development of a T helper (Th)–cell subset producing IL-17. These cells, which are designated Th17, are distinct from Th1 and Th2 populations. Th17 cells are now recognized as a third T-effector cell subset, and the IL-23/IL-17 pathway has been implicated in the induction and progression of a number of inflammatory diseases, including psoriasis.[12]

Environmental factors

Infection and a number of physical agents (eg, HIV infection, alcoholism, smoking, UV light) all can affect the course, duration, and clinical appearance of plaque psoriasis. See Etiology of Plaque Psoriasis, below, for more details on the role of environmental factors.

Etiology

Genetic factors

HLA-B13, -B17, and -Cw6 are all associated with plaque psoriasis. Multifactorial inheritance mechanisms and etiologies without any genetic component have not yet been excluded, although many families appear to exhibit autosomal dominant patterns of inheritance with decreased penetrance. Studies of twin siblings have shown concordant disease in 73% of monozygotic twins compared with 20% in dizygotic twins.

Several putative genetic susceptibility loci have also been identified, including psoriasis susceptibility 1 (PSOR1) on chromosome 6, which is associated with up to 50% of cases. Six other psoriasis susceptibility loci (PSOR2, PSOR3, PSOR4, PSOR5, PSOR6, PSOR7) have been discovered, as well as the transcription factor RUNX1. While this certainly points to genetic mechanisms, the absence of 100% concordance among monozygotes suggests that environmental factors must play a role in the pathophysiology of this disease.

Trauma

All types of trauma have been associated with the development of plaque psoriasis (eg, physical, chemical, electrical, surgical, infective, and inflammatory injury). Even excessive scratching can aggravate or precipitate localized psoriasis. The development of psoriatic plaques at a site of injury is known as the Koebner reaction.

Sunlight

Most patients consider sunlight to be beneficial for their psoriasis; they report a decrease in illness severity during the summer months or periods of increased sun exposure. However, a small minority of patients find that their symptoms are aggravated by strong sunlight, and these individuals actually experience a worsening of their disease in the summer. A severe sunburn can lead to an exacerbation of plaque psoriasis via the Koebner reaction.

Infection

Pharyngeal streptococcal infections have been shown to produce a clinically distinctive disease flare known as guttate psoriasis. Some evidence suggests that subclinical streptococcal colonization or overgrowth could be responsible for refractory plaque psoriasis.

HIV infection

An increase in psoriasis activity has been observed in patients who are infected, or become infected, with HIV. The extent and severity of skin disease initially appears to parallel the disease stage. Psoriasis often becomes less active in advanced HIV infection.

Drugs

A number of medications have been shown to cause an exacerbation of psoriasis. Lithium and withdrawal from systemic corticosteroids are well known to cause flares of disease. Beta-blockers, antimalarials, and nonsteroidal anti-inflammatory drugs (NSAIDs) have also been implicated.

Psychogenic/emotional factors

Many patients report an increase in psoriasis severity with psychological stress. A clear cause-and-effect relationship between disease exacerbation and stress unfortunately has not been proven. Patients may show a decreased capacity to cope with their treatment regimen with higher levels of stress. Pruritus in the setting of increased anxiety or depression may promote scratching and a Koebner reaction.

Smoking

An increased risk of chronic plaque psoriasis exists in persons who smoke cigarettes.

Alcohol consumption

Alcohol consumption is considered a risk factor for psoriasis, particularly in young to middle-aged men.

Endocrinologic factors

Psoriasis severity has been noted to fluctuate with hormonal changes. Disease incidence peaks at puberty and during menopause. During pregnancy, symptoms are more likely to improve than worsen, if any changes occur at all. In contrast, the disease is more likely to flare in the postpartum period, again if any changes occur at all.

Epidemiology

Plaque psoriasis occurs worldwide, although its prevalence varies with race, geography, and environmental factors (eg, sun exposure). In the United States, 1-2% of the population has plaque psoriasis.

Family history has been shown to predict disease occurrence. When both parents are affected by psoriasis, the rate in siblings of probands is as high as 50%. When one parent is affected, the rate is 16.4%. When neither parent has psoriasis, only 7.8% of siblings of probands are affected.

Of patients with psoriasis, 36-71% have one relative who is also affected by psoriasis. For siblings of patients whose psoriasis appeared before age 15 years, a 3-fold higher risk exists of developing disease compared with siblings of patients who first presented after age 30 years.

Psoriasis affects adult males and females equally. Among children and adolescents, plaque psoriasis has been found to affect females more than males, but this observation may be due to the earlier age of onset in females.

Plaque psoriasis first appears during 2 peak age ranges. The first peak occurs in persons aged 16-22 years, and the second occurs in persons aged 57-60 years. Females develop plaque psoriasis earlier than males, and patients with a positive family history for psoriasis also tend to have an earlier age of onset.

Racial disparity in psoriasis

Psoriasis can affect persons of any race; however, epidemiologic studies have shown a higher prevalence in western European and Scandinavian populations. In these groups, 1.5-3% of the population is affected by the disease.

The highest documented disease prevalence is in Arctic Kasach'ye, with 12% of the population affected, followed by Norway, where 4.8% of the population has psoriasis. Lower prevalence rates for psoriasis have been reported among Japanese and Inuit populations.

Psoriasis is thought to be rare in West Africans and African Americans and is nearly absent in North American Indians. Psoriasis was undetected in the Samoan population and in a study that examined 26,000 South American Indians.

Prognosis

The course of plaque psoriasis is unpredictable. Predicting the duration of active disease, the time or the frequency of relapses, or the duration of a remission is impossible. The disease rarely is life threatening but often is intractable to treatment, with relapses occurring in most patients.

Both early onset and a family history of disease are considered poor prognostic indicators. Some suggest that stress is also associated with an unfavorable prognosis.

Environmental factors (particularly sunlight and warm weather) help alleviate the disease and are considered advantageous. Methotrexate, PUVA, cyclosporine, oral retinoids, and biologic therapies all have helped induce and maintain remission in severe cases of plaque psoriasis.

Mortality and morbidity

Disease-related mortality is exceedingly rare in psoriasis. Even then, mortality is related primarily to therapy: systemic corticosteroid therapy may provoke pustular flares of disease, which can be fatal; methotrexate therapy may result in hepatic fibrosis; and phototherapy (eg, psoralen plus UVA [PUVA]) may induce skin cancers, with subsequent metastasis.

Morbidity is a much greater problem in patients with psoriasis; it includes pruritus, dry and peeling skin, fissuring, self-consciousness and embarrassment about appearance, inconvenience, and the adverse effects and high cost of antipsoriatic treatment regimens. By far, reduced quality of life is the most significant morbidity. Studies have demonstrated that patients with psoriasis have deficiencies in quality of life similar to those for persons with congestive heart failure.

An association between psoriasis, obesity, and cardiovascular comorbidity was been recognized amongst patients with plaque psoriasis. This appears to be strongest in younger patients with severe disease. The association seems to be related to the metabolic syndrome, a state of chronic systemic inflammation characterized by at least 3 of the following:

Psoriasis and obesity are now believed to share similar mediators (eg, cytokines tumor necrosis factor [TNF]–alpha and IL-6) that drive the inflammatory process in these conditions. This finding, as it becomes further elucidated, may have future implications on health screening and treatment of patients with psoriasis.[13]

Patient Education

Patient education is one of the foundations for managing this chronic and typically relapsing disorder. Not only is psoriasis associated with morbidity, its treatment can also cause significant adverse effects (even death in rare instances). Patients should be familiar with these details in order to make proper and informed decisions about therapy.

The National Psoriasis Foundation is an excellent organization that provides support to patients with psoriasis.

For patient education information, see the Psoriasis Center, as well as What Is Psoriasis?, Plaque Psoriasis, Types of Psoriasis, Understanding Psoriasis Medications, and Nail Psoriasis.

History

The typical history given by a patient with plaque psoriasis is relatively straightforward: patients report prominent itchy, red areas with increased skin scaling and peeling. Patients are particularly aware of lesions on the scalp and extensor surfaces. Patients typically are self-conscious about their lesions and commonly report using clothing to cover affected sites and avoiding potentially embarrassing social activities.

Patients commonly recognize that new lesions appear at sites of injury or trauma to the skin. This isomorphic phenomenon (Koebner reaction) typically occurs 7-14 days after the skin has been injured and has been found in 38-76% of patients with plaque psoriasis. In some patients, so-called reverse-Koebner reactions have also been noted in which preexisting psoriatic plaques actually clear after injury or trauma to the skin.

Patients may report that their disease worsens in the winter and improves in the summer.

Significant joint pain, stiffness, and deformity are reported in the 10-20% of patients with psoriasis who develop psoriatic arthritis.

Physical Examination

Several cardinal features of plaque psoriasis can be readily observed during the physical examination.

Plaques

Psoriasis manifests as elevated lesions that vary in size from one to several centimeters (see image below). The thickened epidermis, expanded dermal vascular compartment, and infiltrate of neutrophils and lymphocytes account for the psoriatic lesions being raised and easily palpable. The number of lesions may range from few to many at any given time.



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Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

The plaques are irregular to oval and are most often located on the scalp, trunk, and limbs, with a predilection for extensor surfaces such as the elbows and knees. Smaller plaques may coalesce into larger lesions, especially on the legs and sacral regions (see image below). Fissuring within plaques can occur when lesions are present over joint lines or on the palms and soles.



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Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

Well-circumscribed margins

Psoriatic plaques are well defined and have sharply demarcated boundaries. Psoriatic plaques occasionally appear to be immediately encircled by a paler peripheral zone referred to as the halo or ring of Woronoff.

Red color

The color of psoriatic lesions is a very distinctive rich, full, red color. Lesions on the legs sometimes carry a blue or violaceous tint.

Scale

Psoriatic plaques typically have a dry, thin, silvery-white or micaceous scale; however, the amount and thickness of this scale is quite variable. Removing the scale reveals a smooth, red, glossy membrane with tiny punctate bleeding points. These points represent bleeding from enlarged dermal capillaries after removal of the overlying suprapapillary epithelium. This phenomenon is known as the Auspitz sign.

Symmetry

Psoriatic plaques tend to be symmetrically distributed over the body. Lesions typically have a high degree of uniformity with few morphologic differences between the two sides.

Pruritus

Pruritus, one of the main symptoms of plaque psoriasis, is quite variable in intensity but should not be ignored. Emotional instability (eg, high levels of anxiety, depression) that might be induced by the disease often manifests as an increased tendency to scratch.

Nail psoriasis

Nail changes are commonly observed in patients with plaque psoriasis. Nails may exhibit pitting, onycholysis, subungual hyperkeratosis, or the oil-drop sign. A proper assessment of any patient suspected of having psoriasis should include careful examination of the nails.

Psoriasis in children

Plaque psoriasis manifests slightly differently in children. Plaques are not as thick, and the lesions are less scaly. Psoriasis may often appear in the diaper region in infancy and in flexural areas in children. The disease more commonly affects the face in children compared with adults.

Inverse psoriasis

This is a variant of psoriasis that spares the typical extensor surfaces and affects intertriginous (ie, axillae, inguinal folds, inframammary creases) areas with minimal scale.

Psoriatic arthritis

Approximately 10-20% of all cases of plaque psoriasis are associated with psoriatic arthritis. Signs of psoriatic arthritis include the following:

Obesity

Patients with obesity and psoriasis may have an increased risk of cardiovascular disease. This association appears to be strongest in younger patients with severe disease and may be related to the metabolic syndrome.[13]

Alcoholism

Alcoholism can be considered a complication of psoriasis. Male patients with severe disease are particularly at risk for this type of substance abuse.

Laboratory Studies

The diagnosis of psoriasis is almost always made on the basis of clinical findings. Laboratory investigations are rarely indicated. In severe cases, patients may have mild hyperuricemia and low folate levels, presumably because of enhanced epidermopoiesis.

Skin Biopsy

Skin biopsies can confirm the diagnosis of plaque psoriasis; however, this is usually reserved for the evaluation of atypical cases or for excluding other conditions in cases of diagnostic uncertainty. See Histologic Findings for more details on plaque histology.

Histologic Findings

Epidermis

Mitotic activity of basal keratinocytes is increased almost 50-fold, with keratinocytes migrating from the basal to the cornified layers in only 3-5 days rather than the normal 28-30 days. With hyperproliferation of skin cells, the epidermis becomes thickened or acanthotic in appearance and the rete ridges increase in size.

Abnormal keratinocyte differentiation is noted throughout the psoriatic plaques, as manifested by the loss of the granular layer. The stratum corneum is also thickened, and the retention of cell nuclei in this layer is referred to as parakeratosis.

Neutrophils and lymphocytes can be observed migrating upwards from the dermis into the acanthotic epidermis. Neutrophils may form localized collections known as Munro microabscesses. The presence of alternating collections of neutrophils sandwiched between layers of parakeratotic stratum corneum is virtually pathognomonic for psoriasis. (See image below.)



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Plaque psoriasis. Photomicrograph of psoriasis. (1) Hyperkeratosis and parakeratosis, (2) neutrophils in the epidermis, (3) thinning of the epidermis ....

Dermis

Signs of inflammation can be observed throughout the dermis in persons with plaque psoriasis. Marked hypervascularity and an increase in the size of the dermal papillae occur. An activated CD3+ lymphocytic infiltrate is noted around blood vessels, with T cells expressing cutaneous lymphocyte–associated antigen, co-stimulatory molecules such as CD2, and lymphocyte function-associated antigen–1 (LFA-1) adhesion molecules. An aggregation of neutrophils in the dermis occurs that extends up into the epidermis.

Approach Considerations

Plaque psoriasis is a chronic skin condition. Any approach to the treatment of this disease must be considered for the long term. Treatment regimens must be individualized according to age, sex, occupation, personal motivation, other health conditions, and available resources.

Disease severity is defined not only by the number and extent of plaques present but also by the patient's perception and acceptance of the disease. Treatment, therefore, must be designed with the patient's specific expectations in mind rather than the extent of the body surface area involved.[14]

Many treatments exist for psoriasis; however, the construction of an effective therapeutic regimen is not necessarily complicated. Three basic treatment modalities are available for the overall management of psoriasis: topical agents; phototherapy; and systemic agents, including biologic therapies. All of these treatments may be used alone or in combination.

Topical Therapy

Outpatient topical therapy is the first-line treatment of plaque psoriasis. A number of topical treatments are available (eg, corticosteroids, coal tar, anthralin, calcipotriene, tazarotene).[15]

No single topical agent is ideal for plaque psoriasis, and many are often used concurrently in a combined approach. With the different adverse effect profiles for the various agents, using a rotational therapeutic approach in which different topical agents are used sequentially over time in the same patient is common.

In general, the effects of topical therapy should become evident within the first 2-3 weeks of use. Clearing of scale is usually observed first, followed by flattening of the treated plaques. Resolution of erythema may take 6-8 weeks.

Auxiliary agents such as keratolytics can often be added to these preparations. However, some auxiliary agents are incompatible with the active ingredients of these preparations. For example, salicylic acid inactivates calcipotriene. On the other hand, agents such as anthralin require the auxiliary agent salicylic acid for chemical stability.

Phototherapy

Initiate phototherapy only in the presence of extensive and widespread disease (generally practically defined as more lesions than can be easily counted). Resistance to topical treatment is another indication for phototherapy.

The 2 main forms of phototherapy are ultraviolet B (UVB) irradiation and psoralen plus ultraviolet A irradiation (PUVA). Proper facilities are required for both UVB irradiation and PUVA photochemotherapy.

UVB irradiation uses light with wavelengths of 290-320 nm (in comparison, the visible light range is 400-700 nm). Narrow-band UVB phototherapy uses a fluorescent bulb with a narrow emission spectrum that peaks at 311 nm. This selective and relatively longer wavelength is more effective than broadband UVB for the treatment of plaque-type psoriasis, and poses less risk of burning.[16] Excimer laser UVB therapy can deliver high-dose light to limited plaques.

UVB therapy is usually combined with one or more topical treatments. The Goeckerman regimen uses coal tar followed by UVB exposure and has been shown to induce disease remission in more than 80% of patients. The Ingram method comprises anthralin application following a tar bath and UVB treatment. At present, UVB is more commonly combined with topical corticosteroids, calcipotriene, tazarotene, or simply bland emollients. Etanercept and narrow-band UVB combination therapy reportedly was successful.[17]

UVB phototherapy is extremely effective for treating moderate-to-severe plaque psoriasis. The major drawback of this therapy is the time commitment required for treatments and the accessibility of the UVB equipment. Patients may dislike the unpleasant odor when coal tar is added.

Home ultraviolet therapy can overcome some of the logistical problems associated with phototherapy. Because of the expense of the home units, it is most suitable for patients who require long-term maintenance therapy.

PUVA photochemotherapy, also known as PUVA, uses the photosensitizing drug methoxsalen (8-methoxypsoralen) in combination with UVA irradiation to treat patients with more extensive disease. UVA irradiation uses light with wavelengths of 320-400 nm. PUVA interferes with DNA synthesis, decreases cellular proliferation, and induces apoptosis of cutaneous lymphocytes, leading to a localized immunosuppression.

More than 85% of patients report relief of disease symptoms with 20-30 treatments. Therapy is usually administered 2-3 times per week in an outpatient setting, with maintenance treatments every 2-4 weeks until remission.

Adverse effects of PUVA therapy include nausea, pruritus, and a burning sensation. Long-term complications include increased risks of photo damage to the skin and (more importantly) skin cancer. PUVA has been combined with oral retinoid derivatives to decrease the cumulative dose of UVA radiation to the skin.

Also see Clinical Practice Guidelines.

Systemic Agents

Initiate systemic treatment only after both topical treatments and phototherapy have proved unsuccessful. Consider systemic therapy for patients with very active psoriatic arthritis. Patients who have disease that is physically, psychologically, socially, or economically disabling are also considered candidates for systemic treatment. All patients must be informed of the risks and adverse effects of systemic therapy before treatment is initiated.[2, 3, 4]

Plaque psoriasis appears to respond better to combination topical/systemic therapy than to systemic treatment alone. In a randomized study, adding a topical corticosteroid to etanercept therapy in patients with moderate to severe plaque psoriasis proved to be a more effective treatment than etanercept alone.[18] In the study, which involved 592 adult patients with a Psoriasis Area and Severity Index (PASI) score of 10 or higher and with 10% or more of their body surface area affected by psoriasis, treatment consisted of either etanercept alone or etanercept plus topical clobetasol propionate foam. Significant differences favoring combination therapy were seen at week 12, including percentage of improvement in the PASI score (76.5% for combination therapy vs 68.2% for etanercept alone).[18]

Two clinical studies, ESTEEM 1 and ESTEEM 2, showed that patients treated with apremilast experienced significant, clinically meaningful improvement in plaque psoriasis at week 16 as measured by the PASI score. Apremilast was approved by the FDA for the treatment of plaque psoriasis in September 2014.[1]

Biologic Therapies

These relatively new systemic therapies provide selective, immunologically directed intervention at key steps in the pathogenesis of the disease.[5] These steps include the following:

As with the systemic agents, biologic therapies are typically reserved for more severe and recalcitrant cases.[21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32] Patients with active psoriatic arthritis in addition to their skin disease should also be considered.

In a study completed by the Psoriatic Arthritis Study Group, beneficial effects were observed for patients with psoriasis and psoriatic arthritis on stable doses of methotrexate when one or more courses of intramuscular alefacept were added. Further benefit in psoriatic arthritis was apparent after a second course of alefacept, and no additional toxicity was observed.[33]

Also see Clinical Practice Guidelines.

TNF inhibitors

Psoriasis of the palms and soles is more difficult to treat than psoriasis on other body sites. Adalimumab is effective, but only 31% of patients treated with adalimumab for hand or foot psoriasis in a placebo-controlled trial achieved clear or almost clear.[34]  

In 2017, the US Food and Drug Administration (FDA) approved the addition of moderate-to-severe fingernail psoriasis data to the adalimumab (Humira) prescribing information, based on results from a phase 3, multicenter, randomized, double-blind, parallel-arm, placebo-controlled clinical trial.[35]  It is indicated for moderate-to-severe chronic plaque psoriasis in patients who are candidates for systemic therapy or phototherapy and for whom other systemic therapies are inappropriate. Several adalimumab biosimilar products are also approved for plaque psoriasis.

Certolizumab pegol (Cimzia) was approved by the FDA in May 2018 for use in moderate-to-severe plaque psoriasis. Approval was based on data from the CIMPASI-1, CIMPASI-2, and CIMPACT phase 3 clinical trials (n >1000). Nearly one third of participants had prior biologic exposure. The trials included an assessment of patients who achieved at least 75% and 90% improvement from baseline as measured by the Psoriasis Area and Severity Index (PASI) compared with placebo (CIMPASI-1 and CIMPASI-2) and/or etanercept (CIMPACT). Significant improvement was observed by week 16 and meaningful improvements were maintained through 48 weeks.[36, 37]

Interleukin inhibitors

Risankizumab (Skyrizi) is a humanized immunoglobulin G1 (IgG1) monoclonal antibody that selectively binds to the p19 subunit of human interleukin 23 (IL-23) cytokine and inhibits its interaction with the IL-23 receptor. It was approved in April 2019 for treatment of moderate-to-severe plaque psoriasis in adults who are candidates for systemic therapy or phototherapy.

Approval was based on the UltlMMa-1 and UltlMMa-2 replicate phase 3, randomized, double-blind, placebo-controlled and active comparator-controlled international trials (N=997).[20] Coprimary endpoints were proportions of patients achieving a 90% improvement in the PASI 90 and a static Physician's Global Assessment (sPGA) score of 0 or 1 at week 16 (nonresponder imputation). Risankizumab showed superior efficacy to both placebo and ustekinumab in the treatment of moderate-to-severe plaque psoriasis.

At week 16 of each study, PASI 90 was achieved by 74.8-75.3% patients receiving risankizumab compared with 2-4.9% receiving placebo and 42-47.5% receiving ustekinumab (P< .0001 vs placebo and ustekinumab). Results from each trial for sPGA 0 or 1 at week 16 was achieved by 83.7-87.8% patients receiving risankizumab compared with 5.1-7.8% receiving placebo and 61.6-63% receiving ustekinumab (P< .0001 vs placebo and ustekinumab).[20]

Ustekinumab (Stelara), a fully human IL-12 and IL-23 antagonist, is FDA approved to treat adults with moderate or severe psoriasis who may benefit from systemic or phototherapy. Approval was based on data from the phase 3 ACCEPT trial that revealed ustekinumab (administered as 2 subcutaneous injections at weeks 0 and 4) was significantly more effective than etanercept (50 mg injected subcutaneous twice weekly for 12 weeks) for achieving a 75% or greater reduction in psoriasis at week 12, as measured by the PASI 75. At week 12, 68% and 74% of patients receiving ustekinumab 45 mg and 90 mg, respectively, achieved a PASI 75 compared with 57% of patients receiving etanercept.[38]

In October 2017, the FDA expanded its approval to include patients aged 12 years or older. Approval of ustekinumab for adolescents aged 12-17 years with moderate-to-severe plague psoriasis was based on the phase 3, double-blind, placebo-controlled, multicenter CADMUS trial (n=110). Patients were randomly assigned to receive ustekinumab standard dosing (SD) or half-standard dosing (HSD) at weeks 0 and 4 and every 12 weeks thereafter or placebo at weeks 0 and 4 with crossover to either SD or HSD at week 12 and 16 and then every 12 weeks. At week 12, 67.7% and 69.4% of patients receiving ustekinumab HSD and SD achieved Physician’s Global Assessment (PGA) of cleared/minimal psoriasis (PGA 0/1) compared with 5.4% for placebo (P< .001). PASI 75 was 78.4% and 80.6% in HSD and SD, respectively, compared with 10.8% for placebo; PASI 90 was 54.1% and 61.1% in HSD and SD, respectively, compared with 5.4% for placebo.[39]

Guselkumab (Tremfya) was approved by the FDA in July 2017 for adults with moderate-to-severe plaque psoriasis who are candidates for systemic therapy or phototherapy. It is a human monoclonal IgG1-lambda antibody that selectively binds to the p19 subunit of interleukin (IL)–23. IL-23 is a natural cytokine associated with inflammatory and immune responses. Guselkumab inhibits the proinflammatory actions of IL-23, thereby decreasing cytokine and chemokine release.

Approval was based on three phase 3 studies that included more than 2000 patients. In the VOYAGE 1 trial, guselkumab was compared with adalimumab. At 16 weeks, at least 7 of 10 patients treated with guselkumab achieved at least 90% clearer skin (Psoriasis Area and Severity Index [PASI 90]) and more than 80% demonstrated cleared or almost cleared skin. Patients who achieved PASI 90 at week 28 maintained that response at week 48.[40] Similar results were shown in the VOYAGE 2 trial that included adalimumab nonresponders.[41]

Guselkumab also demonstrated effectiveness in patients who had an inadequate response to ustekinumab.[42]

Tildrakizumab (Ilumya) is a high-affinity, humanized, IgG1/κ, anti–IL-23p19 monoclonal antibody that does not bind human IL-12 or p40. In March 2018, the FDA approved tildrakizumab-asmn for moderate-to-severe plaque psoriasis, which is supported by the two pivotal phase 3 trials (reSURFACE 1 and 2).[43]  The two multicenter, randomized, double-blind, placebo-controlled trials involved 926 adults with moderate-to-severe plaque psoriasis, with 616 treated with tildrakizumab-asmn and 310 receiving placebo. Both studies met the primary efficacy endpoints, demonstrating significant clinical improvement with tildrakizumab-asmn compared with placebo when measured by at least a 75% reduction in PASI 75 and PGA score of "clear" or "minimal" at week 12 after two doses.

In the reSURFACE 1 study, 74% of patients achieved PASI 75 at week 28 after three doses of tildrakizumab-asmn and 84% of patients who continued on the drug maintained PASI 75 at week 64, compared with 22% of patients who were rerandomized to placebo. In reSURFACE 2, 66% of the 200-mg group and 61% of the 100-mg group achieved PASI 75, compared with 6% of the placebo group and 48% of the etanercept group at week 12.

The first IL-17A inhibitor, secukinumab (Cosyntex), was approved by the FDA in January 2015. IL-17A is a naturally occurring cytokine that is involved in normal inflammatory and immune responses and plays a key role in the pathogenesis of plaque psoriasis. Approval was based on the efficacy and safety outcomes that included more than 3990 patients.

In two pivotal trials, secukinumab was shown to be superior compared with placebo at week 12 with respect to the proportion of patients who had a reduction of greater than 75% from baseline in the PASI score (PASI 75). The proportion of patients who met the criterion for PASI 75 at week 12 was higher with each secukinumab dose than with placebo or etanercept. In the ERASURE study (Efficacy of Response And Safety of two fixed secUkinumab REgimens in psoriasis), the rates were 81.6% with 300 mg of secukinumab, 71.6% with 150 mg of secukinumab, and 4.5% with placebo. In the FIXTURE study (Full year Investigative eXamination of secukinumab vs. eTanercept Using 2 dosing Regimens to determine Efficacy in psoriasis), the rates were 77.1% with 300 mg of secukinumab, 67% with 150 mg of secukinumab, 44% with etanercept, and 4.9% with placebo (P< .001 for each secukinumab dose vs comparators).[19]

A second IL-17A inhibitor, ixekizumab (Taltz), was approved in March 2016. Efficacy was observed in two prospective, double-blind, multicenter, phase 3 trials (UNCOVER 2, UNCOVER 3) that compared ixekizumab to placebo and etanercept. Ixekizumab (q2wk or q4wk) showed greater efficacy (measured by PASI 75) compared with placebo or etanercept (P< .0001). Greater proportions of patients given ixekizumab achieved PASI 90 by week 2 compared with etanercept in both studies (UNCOVER 2: P=.0002 [ixekizumab q4wk] and P< .0001 [ixekizumab q2wk]; UNCOVER 3: P < .0001 [ixekizumab q4wk] and P=.0001 [ixekizumab q2wk]).[8] IL-17 inhibitors may be associated with a small increase in the incidence of Candida infections.[44]  Additionally, ixekizumab’s prescribing information includes data supporting use for genital plaque psoriasis.

Brodalumab (Siliq), another monoclonal antibody that targets IL-17, was approved in February 2017. Approval was contingent upon including a boxed warning in the prescribing information warning of the risk of suicide and suicidal ideation, particularly in patients with a history of suicidality or depression. Because of the observed suicidal behavior, brodalumab is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS).

Approval of brodalumab was based on data from the AMAGINE phase III pivotal studies. At the 210-mg dose, brodalumab was shown to be effective in total skin clearance of psoriasis compared with placebo and superior to ustekinumab at week 12 in two replicate comparator trials involving over 3500 patients.[9]

Complications

Overly aggressive use of topical steroids could produce progression from plaque psoriasis to generalized pustular or erythrodermic forms. Topical steroids used with occlusion increase the risk of developing cutaneous atrophy. Potential adverse effects of systemic agents and phototherapy should be monitored on a regular basis and treated as soon as possible.

Consultations

Consider consultation with a rheumatologist for patients who have evidence of psoriatic arthritis. Patients with cardiovascular comorbidities should be considered for referral to a cardiologist. Evidence-based guidelines have been published on the management of cardiovascular morbidities.[45]

Diet

Alcohol is considered a risk factor for psoriasis in young to middle-aged males. All patients with psoriasis should avoid or minimize alcohol use; patients with dependency states should be appropriately treated. Otherwise, specific dietary restrictions or supplements other than a well-balanced and adequate diet are unimportant in the management of plaque psoriasis.

Prevention

Avoiding specific exacerbating factors (see Etiology for details) may help prevent or minimize flare-ups of psoriasis in some patients, although the cause of disease exacerbation in many patients often is unknown.

Guidelines Summary

The American Academy of Dermatology has published guidelines of care for the management of psoriasis and psoriatic arthritis. See the following sections:

Clinical Practice Guidelines

Guidelines on psoriasis biologic therapy from the British Association of Dermatologists [52]

Offer biologic therapy to people with psoriasis who require systemic therapy if methotrexate and cyclosporine have failed; if these agents are not tolerated or are contraindicated; and if the psoriasis has a large impact on physical, psychological, or social functioning (eg, Dermatology Life Quality Index [DLQI] or Children's DLQI score >10 or clinically relevant depressive or anxiety symptoms) and one or more of the following disease severity criteria apply:

Consider biologic therapy earlier in the treatment plan (eg, if methotrexate has failed, is not tolerated, or is contraindicated) in people with psoriasis who fulfill the disease severity criteria and who also have active psoriatic arthritis or who have psoriasis that is persistent (ie, that relapses rapidly, defined as >50% baseline disease severity within 3 mo of completion of any treatment) while not on a therapy that cannot be continued in the long term (eg, narrow-band UVB).

Assess whether the minimal response criteria have been met, which are defined by the following:

Specific agents should be used as follows:

Advise women of childbearing potential who are starting biologic therapy for psoriasis to use effective contraception and discuss conception plans with the consultant supervising their care. There are no known interactions between biologic therapies and contraceptive methods.

Advise mothers who have received biologic therapy for psoriasis beyond 16 weeks' gestation that their infants should not receive any live vaccinations until they have reached age 6 months (eg, rotavirus and BCG). Do not give live vaccines to people on biologic therapy or to infants (up to age 6 mo) whose mothers have received biologic therapy beyond 16 weeks' gestation. Stop biologic therapy for at least 6 months before giving live vaccines and for 12 months in the case of the shingles (herpes zoster) vaccine. In general, biologic therapy can be started 4 weeks after administration of a live vaccine. Whenever possible, complete all required vaccinations prior to the initiation of biologic therapy, and review vaccination requirements during therapy with reference to the Green Book and the clinical risk category of “immunosuppression.”

Do not use TNF antagonists in people with demyelinating diseases, and review alternative interventions in people who have an affected first-degree relative with demyelinating disease. Stop treatment and seek specialist advice if neurologic symptoms suggestive of demyelinating disease develop during TNF antagonist therapy. Symptoms include loss or reduction of vision in one eye with painful eye movements; double vision; ascending sensory disturbance and/or weakness; problems with balance, unsteadiness, or clumsiness; and altered sensation traveling down the back and sometimes into the limbs when bending the neck forward.

Avoid TNF antagonist therapy in people with severe cardiac failure. Stop TNF antagonist therapy in the event of new or worsening preexisting heart failure and seek specialist advice.

Exercise caution and consult a gastroenterology specialist before using secukinumab or ixekizumab in people with inflammatory bowel disease.

Guidelines on the management and treatment of psoriasis with biologics by the American Academy of Dermatology and the National Psoriasis Foundation [53]

TNF-alpha inhibitors

Etanercept recommendations are as follows:

Infliximab recommendations are as follows:

Adalimumab recommendations are as follows:

Certolizumab has been approved by the FDA for the treatment of plaque psoriasis, psoriatic arthritis, Crohn disease, ankylosing spondylitis, and rheumatoid arthritis. Approved dosing for moderate-to-severe psoriasis is 400 mg (two 200-mg SC injections) every other week. It is likely to possess class characteristics similar to those of other TNF-alpha inhibitors.

Interleukin-12/23 inhibitors

Ustekinumab recommendations are as follows:

Interleukin-17 inhibitors

Secukinumab recommendations are as follows:

Ixekizumab recommendations are as follows:

Brodalumab recommendations are as follows:

Interleukin-23 inhibitors

Guselkumab recommendations are as follows:

Tildrakizumab recommendations are as follows:

Risankizumab was approved by the FDA in April 2019. It can be used as monotherapy in adults with moderate-to-severe plaque psoriasis. A suggested dose is 150 mg given by self-administered subcutaneous injections at week 0 and week 4, followed by every 12 weeks.

Guidelines on the m anagement and treatment of psoriasis with phototherapy from the American Academy of Dermatology and the National Psoriasis Foundation [54]

Narrowband ultraviolet B phototherapy

Phototherapy using narrowband ultraviolet B (NB-UVB) is recommended as monotherapy for adults with plaque psoriasis.

For adults with generalized plaque psoriasis, the recommended NB-UVB phototherapy starting dose should be based on the minimal erythema dose or it should be determined based on a fixed-dose or skin-phototype protocol.

For adults with generalized plaque psoriasis, a treatment phase of thrice-weekly dosing of NB-UVB phototherapy is recommended.

For adults with psoriasis, treatment with short-term psoralen plus ultraviolet A (PUVA) monotherapy is more effective than NB-UVB.

Owing to its increased safety, higher convenience, and lower cost, NB-UVB is preferred over PUVA monotherapy for psoriasis in adults, even though it is less effective.

In adults with generalized plaque psoriasis, NB-UVB is recommended over broadband ultraviolet B (BB-UVB) monotherapy.

Treatment with NB-UVB monotherapy is recommended for guttate psoriasis patients, regardless of their age.

For appropriate patients with generalized plaque psoriasis, home-based NB-UVB phototherapy is recommended as an alternative to in-office NB-UVB phototherapy.

Treatment with NB-UVB phototherapy is recommended for pregnant patients who have guttate psoriasis or generalized plaque psoriasis.

As a measure to possibly improve efficacy, NB-UVB phototherapy can be safely augmented with concomitant topical therapy using retinoids, vitamin D analogues, and corticosteroids.

Oral retinoids can be combined with NB-UVB phototherapy in appropriate patients with generalized plaque psoriasis if they have not responded adequately to monotherapy.

Owing to an increased risk of developing skin cancer, long-term combination therapy with NB-UVB and cyclosporine is not recommended for adults with generalized plaque psoriasis.

Apremilast combined with NB-UVB phototherapy can be considered for adult patients with generalized plaque psoriasis if they have not responded adequately to monotherapy.

To reduce the risk of genital skin cancer, all patients receiving NB-UVB phototherapy should be provided genital shielding.

To reduce the risk of ocular toxicity, all patients receiving NB-UVB phototherapy should be provided eye protection with goggles.

Owing to the risk of photocarcinogenesis, use caution when administering NB-UVB phototherapy to patients with a history of melanoma or multiple nonmelanoma skin cancers, arsenic intake, or prior exposure to ionizing radiation.

Folate supplementation is recommended for females of childbearing age who are receiving NB-UVB phototherapy.

To maintain the clinical response from NB-UVB phototherapy, maintenance therapy can be considered.

BB-UVB phototherapy

In adults with generalized plaque psoriasis, BB-UVB phototherapy is recommended as monotherapy if NB-UVB is not available.

In adults with generalized plaque psoriasis, BB-UVB monotherapy is considered less efficacious than NB-UVB or oral PUVA monotherapy.

Monotherapy with BB-UVB may be considered for adults with guttate psoriasis.

To reduce the risk of genital skin cancer, all patients being offered BB-UVB phototherapy should be provided with genital shielding.

To reduce the risk of ocular toxicity, all patients receiving BB-UVB phototherapy should be provided eye protection with goggles.

Owing to the risk of photocarcinogenesis, use caution when administering BB-UVB phototherapy to patients with a history of melanoma or multiple nonmelanoma skin cancers, arsenic intake, or prior exposure to ionizing radiation.

Combination therapy with acitretin and BB-UVB can be considered in adults with generalized plaque psoriasis.

Targeted UVB phototherapy

The recommended targeted UVB phototherapy for adults with localized plaque psoriasis (< 10% body surface area), for individual plaque psoriasis lesions, or for patients with more extensive disease includes excimer 308-nm laser, excimer 308-nm light, and targeted NB-UVB 311- to 313-nm light.

For maximal efficacy, the recommended treatment frequency for targeted UVB phototherapy in adults with localized plaque psoriasis is 2-3 times per week, rather than once every 1-2 weeks.

In adults with localized plaque psoriasis, the initial dose of targeted UVB phototherapy is based on the minimal erythema dose or by a fixed-dose or skin-phototype protocol.

For treating localized plaque psoriasis in adults, the most effective targeted UVB phototherapy is excimer 308-nm laser, followed by excimer 308-nm light, followed by localized NB-UVB 311- to 312-nm light.

For adults with plaque psoriasis (including palmoplantar psoriasis), a recommended targeted UVB phototherapy includes excimer 308-nm laser and excimer 308-nm light.

Treatment of plaque psoriasis in adults with excimer 308-nm laser may be combined with topical steroid therapy.

A recommended targeted UVB phototherapy treatment for adults with scalp psoriasis is excimer 308-nm laser.

PUVA therapy

In the treatment of localized plaque psoriasis in adults, particularly those with palmoplantar psoriasis or palmoplantar pustular psoriasis, topical phototherapy with PUVA is deemed superior to NB-UVB 311- to 313-nm light.

A recommended treatment for psoriasis in adults is oral PUVA.

A recommended treatment for moderate-to-severe psoriasis in adults is bath PUVA.

Photodynamic therapy

Photodynamic therapy with either aminolevulinic acid or methyl aminolevulinate is not recommended for adults with localized psoriasis, including the palmoplantar variety or nail psoriasis.

Grenz ray, climatotherapy, visible light, Goeckerman, and pulsed-dye laser therapies

Evidence is insufficient to recommend grenz ray therapy (long-wavelength ionizing radiation) for the treatment of psoriasis.

Sufficient evidence exists to recommend climatotherapy (temporary or permanent relocation geographically) for the treatment of psoriasis.

Evidence is insufficient to recommend the use of visible light (blue or red) as a more effective treatment for psoriasis, except in nail psoriasis.

Sufficient evidence exists to recommend Goeckerman therapy (coal tar in combination with UVB phototherapy) for the treatment of psoriasis.

Pulsed-dye laser can be considered for nail psoriasis.

Medication Summary

Drug therapy for psoriasis may involve topical and systemic medications in conjunction with phototherapy and moisturizers.

Triamcinolone topical (Kenalog topical, Pediaderm TA)

Clinical Context:  Triamcinolone treats inflammatory dermatosis responsive to steroids. It decreases inflammation by suppressing the migration of polymorphonuclear leukocytes and reversing capillary permeability. It has mild potency and is the first drug of choice for most patients.

Betamethasone topical (Diprolene, Luxiq)

Clinical Context:  Betamethasone treats inflammatory dermatosis responsive to steroids. It decreases inflammation by suppressing the migration of polymorphonuclear leukocytes and reversing capillary permeability. It is a potent topical steroid and is the drug of choice if psoriasis is resistant to milder forms.

Halobetasol (Bryhali, Lexette, Ultravate)

Clinical Context:  Halobetasol is available in lotion and foam preparations for the treatment of plaque psoriasis.

Class Summary

Topical corticosteroids are the mainstay of treatment for mild and limited psoriasis. They can reduce plaque formation. These agents have anti-inflammatory effects and may cause profound and varied metabolic activities.

Calcitriol topical (Vectical)

Clinical Context:  Calcitriol is a topical vitamin D analog similar to calcipotriene but seems to be less irritating in sensitive areas of skin.

Calcipotriene (Calcitrene Ointment, Dovonex, Sorilux)

Clinical Context:  Calcipotriene is a synthetic vitamin D-3 analog that regulates skin cell production and development. It is used in the treatment of moderate plaque psoriasis. This treatment does not cause long-term skin thinning or systemic effects. Sorilux is a newer foam version of this medication.

Calcipotriene/betamethasone (Enstilar, Taclonex Ointment, Taclonex Topical Suspension)

Clinical Context:  Calcipotriene is a synthetic vitamin D-3 analog that regulates skin cell production and development. It inhibits epidermal proliferation, promotes keratinocyte differentiation, and has immunosuppressive effects on lymphoid cells. Betamethasone is a corticosteroid that decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing capillary permeability. The combination is available as a topical ointment, foam, or as a solution that can be applied to the body or scalp. The products contain calcipotriene 0.005% and betamethasone dipropionate 0.064%.

The combination product is quite expensive and the same results may be obtained by using a generic corticosteroid sequentially in combination with one of the other vitamin D analog products.

Tazarotene (Avage, Fabior, Tazorac)

Clinical Context:  Tazarotene is a retinoid prodrug that is converted to its active form in the body and modulates differentiation and proliferation of epithelial tissue and perhaps has anti-inflammatory and immunomodulatory activities. It may be the drug of choice for those with facial lesions who are not at risk of pregnancy.

Tazarotene, although topical, is a category X medication. Topical tretinoin is of less use in psoriatic patients. A strategy that may be tried in patients who experience unacceptable irritation is to use short contact times. There are several protocols, but the least irritating is to apply the medication for 15-20 min and then wash off. The total time on may be increased by 15-20 minutes every few weeks until clinical efficacy or adverse cutaneous effects are seen. This short-contact method may be especially useful when one is using it in skin folds but is less effective for the plaque with very thick scale.

Coal tar topical (Fototar, Medotar, Oxipor VHC)

Clinical Context:  Coal tar is antipruritic and antibacterial and inhibits deregulated epidermal proliferation and dermal infiltration. It does not injure the normal skin when applied widely, and it enhances the usefulness of phototherapy. It generally is used as a second-line drug therapy owing to messy application, except for shampoos, which may be used and rinsed at once.

Anthralin (Dritho-Scalp)

Clinical Context:  Anthralin reduces the rate of cell proliferation. Its chemically reducing properties may also upset the oxidative metabolic processes, further reducing epidermal mitosis. It is not the first or second drug of choice owing to irritation problems of normal skin surrounding lesions and staining of the skin.

Class Summary

Keratolytic agents are used to remove scale, to smooth the skin, and to treat hyperkeratosis.

Halobetasol/tazarotene (Duobrii)

Clinical Context:  Halobetasol is indicated for the treatment of plaque psoriasis in adults. It is  a combination lotion containing a topical corticosteroid and a retinoid.

Class Summary

Combination topical products with differing mechanisms of actions are available to improve ease of application.

Risankizumab (Skyrizi, risankizumab-rzaa)

Clinical Context:  Risankizumab is a humanized immunoglobulin G1 (IgG1) monoclonal antibody that selectively binds to the p19 subunit of IL-23 cytokine and inhibits its interaction with the IL-23 receptor. IL-23 is a naturally occurring cytokine that is involved in inflammatory and immune responses. It is indicated for treatment of moderate-to-severe plaque psoriasis in adults who are candidates for systemic therapy or phototherapy.

Tildrakizumab (Ilumya, tildrakizumab-asmn)

Clinical Context:  This humanized IgG1/k monoclonal antibody selectively binds to the p19 subunit of IL-23 and inhibits its interaction with the IL-23 receptor. IL-23 is a natural cytokine associated with inflammatory and immune responses. Tildrakizumab inhibits the release of proinflammatory cytokines and chemokines. It is indicated for adults with moderate-to-severe plaque psoriasis who are candidates for systemic therapy or phototherapy.

Guselkumab (Tremfya)

Clinical Context:  Guselkumab is a human monoclonal IgG1-lambda antibody that selectively binds to the p19 subunit of IL-23. IL-23 is a natural cytokine associated with inflammatory and immune responses. Guselkumab inhibits the proinflammatory actions of IL-23, thereby decreasing cytokine and chemokine release. It is indicated for adults with moderate-to-severe plaque psoriasis who are candidates for systemic therapy or phototherapy.

Ustekinumab (Stelara)

Clinical Context:  Ustekinumab is a human monoclonal antibody directed against IL-12 and IL-23, thereby interfering with T-cell differentiation and activation and subsequent cytokine cascades. It is indicated for moderate-to-severe plaque psoriasis.

Brodalumab (Siliq)

Clinical Context:  Brodalumab is a human monoclonal IgG2 antibody that selectively binds to the human IL-17A receptor and inhibits its interactions with cytokines IL-17A, IL-17F, IL-17C, IL-17A/F heterodimer, and IL-25. It is indicated for moderate-to-severe plaque psoriasis in adults who are candidates for systemic therapy or phototherapy and have failed to respond or have lost response to other systemic therapies.

Secukinumab (Cosentyx)

Clinical Context:  Secukinumab is a human IgG1 monoclonal antibody that selectively binds to and neutralizes the proinflammatory cytokine IL-17A. IL-17A is a naturally occurring cytokine that is involved in normal inflammatory and immune responses and plays a key role in the pathogenesis of plaque psoriasis. Following the initial once-weekly SC dosage regimen, the drug is given as a maintenance dose once monthly. It is indicated for moderate-to-severe plaque psoriasis in patients who are candidates for systemic therapy or phototherapy.

Ixekizumab (Taltz)

Clinical Context:  Ixekizumab is a humanized monoclonal IgG4 antibody that targets IL-17A and neutralizes the proinflammatory effects of IL-17A. It is administered as a SC injection. It is indicated for adults with moderate-to-severe plaque psoriasis.

Class Summary

Interleukins (ILs) play key roles in the pathogenesis of plaque psoriasis.

Apremilast (Otezla)

Clinical Context:  Apremilast is a phosphodiesterase-4 inhibitor specific for cAMP, resulting in increased intracellular cAMP levels. It may affect cytokines and chemokine synthesis, leading to anti-inflammatory effects. It is indicated for moderate-to-severe plaque psoriasis in adults who are candidates for phototherapy or systemic therapy.

Class Summary

The mechanisms by which phosphodiesterase-4 (PED4) inhibitors elicit anti-inflammatory effects are not completely understood. Unlike biologics that neutralize inflammatory mediators at the protein level, apremilast modulates mediator production at the level of mRNA expression.

Methotrexate (Otrexup, Rasuvo, Trexall)

Clinical Context:  Methotrexate inhibits dihydrofolic acid reductase. Dihydrofolates must be reduced to tetrahydrofolates by this enzyme before they can be utilized as carriers of one-carbon groups in the synthesis of nucleotides and thymidylate. Subsequently, methotrexate interferes with DNA synthesis, repair, and cellular replication. Actively proliferating tissues are in general more sensitive to this effect of methotrexate.

Infliximab (Remicade, Inflectra, Renflexis, Ixifi )

Clinical Context:  Infliximab is a chimeric antibody that binds both the soluble and transmembrane TNF-α molecules, thereby neutralizing the effects of TNF-α. It is indicated for chronic severe (ie, extensive and/or disabling) plaque psoriasis in adults who are candidates for systemic therapy and when other systemic therapies are medically less appropriate. It is also indicated to reduce signs and symptoms, and to improve physical function of patients with psoriatic arthritis. Screen patients for tuberculosis (TB) and hepatitis B, as reactivation of both illnesses is associated with TNF-α inhibitors.

Adalimumab (Amjevita, Cyltezo, Humira, Hadlima, Hyrimoz, Adalimumab-atto, Adalimumab-adbm, Adalimumab-bwwd, Adalimumab-adaz)

Clinical Context:  Adalimumab is a fully human anti–TNF-α monoclonal antibody. It binds specifically to soluble and membrane-bound TNF-α, thereby neutralizing the effects of TNF-α. It is used to treat moderate-to-severe psoriasis and moderate-to-severe psoriatic arthritis. Screen patients for TB and hepatitis B, as reactivation of both illnesses is associated with TNF-α inhibitors. The FDA approved adalimumab-atto, adalimumab-adbm, adalimumab-adaz, and adalimumab-bwwd as biosimilars and not as interchangeable drugs.

Etanercept (Enbrel, Eticovo)

Clinical Context:  Etanercept is a recombinant human TNF-α receptor protein fused with the Fc portion of IgG1 that binds to soluble and membrane-bound TNF-α, thereby neutralizing the effects of TNF-α. It is indicated for adults and children aged 4 years and older with moderate-to-severe psoriasis. It is also indicated for adults with moderate-to-severe psoriatic arthritis. Screen patients for TB and hepatitis B, as reactivation of both illnesses is associated with TNF-α inhibitors.

Certolizumab pegol (Cimzia)

Clinical Context:  Certolizumab pegol is indicated for moderate-to-severe plaque psoriasis. It is a pegylated anti–TNF-α blocker, and its action results in disruption of the inflammatory process.

What is plaque psoriasis?What are the signs and symptoms of plaque psoriasis?How is plaque psoriasis diagnosed?How is plaque psoriasis treated?How is plaque psoriasis characterized?What is the pathophysiology of plaque psoriasis?What is the role of environmental factors in the pathophysiology of plaque psoriasis?What is the role of genetics in the etiology of plaque psoriasis?What is the role of trauma in the etiology of plaque psoriasis?What is the role of sunlight exposure in the etiology of plaque psoriasis?What is the role streptococcal infection in the etiology of plaque psoriasis?What is the role of HIV infection in the etiology of plaque psoriasis?What is the role of medications in the etiology of plaque psoriasis?What is the role of stress in the etiology of plaque psoriasis?What is the role of smoking in the etiology of plaque psoriasis?What is the role of alcohol consumption in the etiology of plaque psoriasis?What is the role of hormones in the etiology of plaque psoriasis?What is the prevalence of plaque psoriasis?What are the sexual predilections of plaque psoriasis?Which age groups have the highest prevalence of plaque psoriasis?What are the racial predilections of plaque psoriasis?What is the prognosis of plaque psoriasis?What is the mortality and morbidity associated with plaque psoriasis?What is included in patient education about plaque psoriasis?Which clinical history findings are characteristic of plaque psoriasis?How are the lesions of plaque psoriasis characterized?How are the margins of plaque psoriasis lesions characterized?How the color of plaque psoriasis lesions characterized?How are the scales of plaque psoriasis lesions characterized?What is the typical distribution of plaque psoriasis lesions on the body?How is pruritus of plaque psoriasis lesions characterized?Which physical findings of the nails are characteristic of plaque psoriasis?Which physical findings are characteristic of plaque psoriasis in children?Which physical findings are characteristic of inverse psoriasis?Which physical findings are characteristic of psoriatic arthritis?Which risks are increased in obese patients with plaque psoriasis?Which patient groups with plaque psoriasis have the highest risk of alcoholism?What are the differential diagnoses for Plaque Psoriasis?What is the role of lab tests in the workup of plaque psoriasis?What is the role of skin biopsy in the workup of plaque psoriasis?Which epidermis histologic findings are characteristic of plaque psoriasis?Which dermis histologic findings are characteristic of plaque psoriasis?What are the approaches to the treatment of plaque psoriasis?What is the role of topical therapy in the treatment of plaque psoriasis?What is the role of phototherapy in the treatment of plaque psoriasis?What is the role of systemic therapy in the treatment of plaque psoriasis?What is the role of biologic therapies in the treatment of plaque psoriasis?What is the role of TNF inhibitors in the treatment of plaque psoriasis?What is the role of interleukin inhibitors in the treatment of plaque psoriasis?What are the possible complications of plaque psoriasis?Which specialist consultations are beneficial to patients with plaque psoriasis?Which dietary modifications are used in the treatment of plaque psoriasis?How are flare-ups of plaque psoriasis prevented?Which organization has released guidelines on the treatment of plaque psoriasis?What are the biologics and phototherapy guidelines for plaque psoriasis?What is the role of medications in the treatment of plaque psoriasis?Which medications in the drug class Tumor Necrosis Factor Inhibitors are used in the treatment of Plaque Psoriasis?Which medications in the drug class Immunosuppressants are used in the treatment of Plaque Psoriasis?Which medications in the drug class DMARDs, PDE4 Inhibitors are used in the treatment of Plaque Psoriasis?Which medications in the drug class Interleukin Inhibitors are used in the treatment of Plaque Psoriasis?Which medications in the drug class Topical Combinations are used in the treatment of Plaque Psoriasis?Which medications in the drug class Keratolytic Agents are used in the treatment of Plaque Psoriasis?Which medications in the drug class Antipsoriatics, Topical are used in the treatment of Plaque Psoriasis?Which medications in the drug class Corticosteroids, Topical are used in the treatment of Plaque Psoriasis?

Author

Harvey Lui, MD, FRCPC, Professor and Head, Department of Dermatology and Skin Science, Vancouver General Hospital, University of British Columbia; Medical Director, The Skin Centre, Lions Laser Skin Centre and Psoriasis and Phototherapy Clinic, Vancouver General Hospital

Disclosure: Received consulting fee from Astellas for review panel membership; Received consulting fee from Amgen/Wyeth for speaking and teaching; Received honoraria from LEO Pharma for speaking and teaching; Received grant/research funds from LEO Pharma for investigator; Received grant/research funds from Galderma for other.

Coauthor(s)

Adam J Mamelak, MD, FRCPC, Attending Physician, Division of Dermatology, The Ottawa Hospital, University of Ottawa

Disclosure: Nothing to disclose.

Specialty Editors

Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University Health Sciences Center, Paul L Foster School of Medicine; Consulting Staff, Mountain View Dermatology, PA

Disclosure: Nothing to disclose.

Christen M Mowad, MD, Professor, Department of Dermatology, Geisinger Medical Center

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD, Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Disclosure: Nothing to disclose.

Additional Contributors

Mark G Lebwohl, MD, Chairman, Department of Dermatology, Mount Sinai School of Medicine

Disclosure: Received none from Amgen for consultant & investigator; Received none from Novartis for consultant & investigator; Received none from Pfizer for consultant & investigator; Received none from Celgene Corporation for consultant & investigator; Received none from Clinuvel for consultant & investigator; Received none from Eli Lilly & Co. for consultant & investigator; Received none from Janssen Ortho Biotech for consultant & investigator; Received none from LEO Pharmaceuticals for consultant & inves.

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Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

Plaque psoriasis. Photomicrograph of psoriasis. (1) Hyperkeratosis and parakeratosis, (2) neutrophils in the epidermis, (3) thinning of the epidermis overlying the dermal papillae, (4) vessels close to the epidermis, and (5) elongated rete ridges. Courtesy of Richard Crawford, MD, University of British Columbia, Department of Dermatology and Skin Science.

Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

Plaque psoriasis. Photomicrograph of psoriasis. (1) Hyperkeratosis and parakeratosis, (2) neutrophils in the epidermis, (3) thinning of the epidermis overlying the dermal papillae, (4) vessels close to the epidermis, and (5) elongated rete ridges. Courtesy of Richard Crawford, MD, University of British Columbia, Department of Dermatology and Skin Science.