by Kristy Fleming, MD
An 8-year-old boy presented complaining of an approximately one-year history of diffuse papules covering the majority of his body surface area. The papules were occasionally pruritic, but the boy was otherwise healthy and not taking any medications. The lesions had been present and unchanged over the course of the past year. He was not applying any creams or lotions topically and his mother denied any change in soap, detergent or fabric softener. Neither family members, nor classmates had similar lesions.Submit your answer, and then read the full explanation below. If you like this activity or have a suggestion, tell us about it in the comment box at the bottom of the page.
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Lichen nitidus is a relatively uncommon, completely benign cutaneous eruption of unknown etiology.1 People of any age may be affected, but the eruption is seen most commonly in preschool and school-aged children.
No causative infectious agents or underlying systemic diseases have been associated with the condition. Some experts consider lichen nitidus to be a variant of lichen planus, as two conditions may occur concurrently, whereas others consider the two to be separate entities with distinct clinical and histopathologic features.2
The individual lesions of lichen nitidus are well-demarcated 0.5 mm to 2 mm skin-colored, round or flat-topped papules.1,2 Oftentimes, the lesions appear to have a shiny hue when viewed in tangential lighting. The lesions occasionally have a slight central depression, but this is not as pronounced as the central dell or umbilication seen with molluscum contagiosum papules.
Lichen nitidus papules may appear in groups, linear streaks (representing Koebner phenomena) or more rarely, cover diffuse body surface areas. Common sites of involvement include the trunk, genitalia, forearms and dorsal hands; less commonly the face, neck, and lower extremities are involved.2
Differentiation of lichen nitidus from early lichen planus or flat warts can sometimes be difficult. The patient’s history is often helpful, but in ambiguous cases a skin biopsy will confirm the diagnosis, as lichen nitidus has a characteristic constellation of histopathologic findings.
The overlying epidermis exhibits parakeratosis with thinning to absence of the granular layer, and liquefaction degeneration of the basal layer is also present. A characteristic “ball and claw” configuration is commonly apparent, with the “ball” representing a focal collection of papillary dermal lymphocytes closely approximating the epidermis, and the “claw” representing elongated rete ridges embracing the infiltrate. Multinucleated giant cells may also appear within the infiltrate. 3
The natural course of lichen nitidus is spontaneous resolution, but the duration is highly variable. Some cases resolve over a period of a few weeks, while others persist for years. The majority of cases resolve within one year.1
There are several treatment options available to relieve lesions that are pruritic; however, none have been rigorously evaluated due to the rarity of lichen nitidus and it’s self-limited nature. Topical corticosteroids and oral antihistamines are the traditional mainstay of first-line treatment.2 More recently, topical calcineurin inhibitors have been shown to be effective in the management of lichen nitidus in children.2 In cases of generalized lichen nitidus which have failed topical treatments, light therapy with either narrowband UV-B light or photochemotherapy may be successful.
1. Paller AS, Mancini AJ. Hurwitz Clinical Pediatric Dermatology, 3rd Ed. Elsevier; 2006:103-104.
2. Bolognia J, Jorizzo JL, Rapini RP. Dermatology, 2nd Ed. Elsevier; 2008:172-174.
3. Rapini R. Practical Dermatopathology. Elsevier; 2005: 56-57.