Lichen nitidus is a relatively rare, chronic skin eruption that is characterized clinically by asymptomatic, flat-topped, skin-colored micropapules (see image below).[1] Lichen nitidus mainly affects children and young adults.[2]
 View Image | Multiple skin-colored shiny papules associated with lichen nitidus. |
The skin is the primary organ system affected. Mucous membranes and nails[3] also might be involved. Lichen planus can clinically mimic lichen nitidus and can sometimes coexist with lichen nitidus.
The etiology of lichen nitidus is unknown. Controversy exists regarding the relationship between lichen planus and lichen nitidus.[4]
The frequency of lichen nitidus is unknown because of its uncommon occurrence. In a study of skin diseases in blacks over a 25-year period, the incidence of lichen nitidus was 0.034%.[5]
No racial predilection is reported.
No sexual predilection exists. However, generalized variants appear to occur predominantly in females.
Lichen nitidus may affect any age group, but it most commonly develops in childhood or early adulthood.
Lichen nitidus is a benign disease with no associated mortality or complications. Lichen nitidus may remain active for several years; however, spontaneous resolution usually occurs.
Lichen nitidus is usually an asymptomatic eruption; however, patients occasionally complain of pruritus. Familial cases have been described.[6]
The primary lesions consist of multiple 1- to 3-mm, sharply demarcated, round or polygonal, flat-topped, skin-colored shiny papules that often appear in groups (see image below).
View Image | Multiple shiny lichens over the penis. |
The Köbner phenomenon (or an isomorphic response) may be observed, as shown below. This phenomenon causes the occasional linear pattern of the lesions associated with lichen nitidus.
View Image | Köbner phenomenon in lichen nitidus. |
The most common sites of involvement are the trunk, flexor aspects of upper extremities, dorsal aspects of hands (see image below), and genitalia. Infrequently, the lower extremities, palms, soles, face, nails, and mucous membranes may be affected. Nail changes include pitting, ridging, splitting, and linear striations.
View Image | Lichen nitidus. |
Clinical variants of lichen nitidus include generalized,[7] linear, actinic,[8] perforating,[9, 10] keratodermic,[11, 12] vesicular,[13] and purpuric[10] /hemorrhagic[13] forms.
Reported associated diseases include atopic dermatitis,[14] lichen planus,[15] condyloma,[16] amenorrhea,[17] Crohn disease,[18, 19] , juvenile chronic arthritis,[20] and Down syndrome.[21, 22]
A skin biopsy for histopathologic examination may be obtained to confirm the clinical diagnosis.
The papule of lichen nitidus consists of a lymphohistiocytic inflammatory cell infiltrate that lies in close proximity to the epidermis and is associated with basal cell hydropic degeneration. The overlying epidermis is flattened and parakeratotic. At the lateral margins of the papule, the rete ridges extend downward and seem to hug the inflammatory infiltrate, which may be granulomatous.
No therapeutic modality has been rigorously evaluated for the treatment of lichen nitidus because of the rarity, lack of significant symptomatology, and disappearance of this disease within one or several years. Reported therapies, mostly from isolated case reports, include topical and systemic steroids, topical tacrolimus,[23, 24, 25] systemic cetirizine,[26] levamisole,[26] etretinate, acitretin,[27] itraconazole,[28] cyclosporine, topical dinitrochlorobenzene,[29] psoralen plus UV-A light,[30] and narrow-band UV-B light.[31, 32, 33]
Clinical Context: Prednisone may decrease inflammation by reversing increased capillary permeability and suppressing PMN activity.
Clinical Context: Methylprednisolone decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.
Corticosteroids have anti-inflammatory properties and cause profound and varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli.
Clinical Context: Cetirizine forms complex with histamine for H1-receptor sites in blood vessels, GI tract, and respiratory tract.
Antihistamines act by competitive inhibition of histamine at the H1 receptor. They mediate bronchial constriction, mucous secretion, smooth muscle contraction, edema, hypotension, CNS depression, and cardiac arrhythmias.
Clinical Context: Acitretin is a retinoic acid analog, like etretinate and isotretinoin. Etretinate is the main metabolite and has demonstrated clinical effects close to those seen with etretinate. Its mechanism of action is unknown.
Multiple skin-colored shiny papules associated with lichen nitidus.
Multiple shiny lichens over the penis.
Köbner phenomenon in lichen nitidus.
Lichen nitidus.
Multiple skin-colored shiny papules associated with lichen nitidus.
Multiple shiny lichens over the penis.
Köbner phenomenon in lichen nitidus.
Lichen nitidus.
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