Lichen Nitidus

Lichen nitidus is a relatively rare, chronic skin eruption that presents with flat-topped, skin-colored small bumps. The cause of lichen nitidus is unknown. Lichen nitidus mainly affects children and young adults. The skin is the primary organ system affected. Mucous membranes and nails also might be involved. 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%. Lichen nitidus usually has no sympstoms. Patients occasionally complain of itching.

Epidemiology:
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.

Presentation:
The eruption consist of multiple 1- to 3-mm, sharply demarcated, round, flat-topped, skin-colored shiny bumps that often appear in groups. The Koebner phenomenon (lesions appearing in areas of trauma) may be observed. The most common sites of involvement are the trunk, flexor aspects of upper extremities, dorsal aspects of hands, and genitalia. Infrequently, the lower extremities, palms, soles, face, nails, and mucous membranes may be affected. Nail changes can be observed as well.

Reported associated diseases include atopic dermatitis, lichen planus, condyloma, amenorrhea, Crohn disease, and juvenile chronic arthritis.

Treatment:
Usually the diagnosis is made by visual examination. A skin biopsy may be obtained to confirm the clinical diagnosis. No therapeutic modality has been thoroughly evaluated for the treatment of lichen nitidus because of the rarity, largely asymptomatic nature, and disappearance of this disease within 1 or several years. Reported therapies, mostly from isolated case reports, include topical and systemic steroids, topical tacrolimus, systemic cetirizine, levamisole, etretinate, acitretin, itraconazole, cyclosporine, topical dinitrochlorobenzene, psoralen plus UV-A light, and narrow-band UV-B light.

Prognosis:
Lichen nitidus may remain active for several years; however, spontaneous resolution usually occurs. There is no associated morbidity or mortality.

Valerie Nozad, D.O.
Department of Dermatology
Philadelphia College of Osteopathic Medicine/Frankford Hospital
Philadelphia, Pennsylvannia.