Annular lichenoid dermatitis of youth (ALDY).

Abstract

ALDY was identified in 2003 by Annessi and Paradisi (1). So far less than 60 cases have been described in the world literature, but its incidence would increase if a biopsy was performed in all cases of clinically suspected superficial scleroderma or patch mycosis fungoides, two conditions that have a clinical course similar to ALDY. Initially described in the Mediterranean basin, ALDY was later also reported in America (6), Japan (4) and elsewhere. ALDY shows no sex preference (33 M, 25 F) and the average age at diagnosis is in the peripubertal period, ranging between 2 (4) and 79 (3) years. We do not know the cause even if hepatitis B vaccination (7), Borrelia (8), contact allergy (2) and mycosis fungoides (5) were hypothesized. The lesions almost always affect the lower trunk and are single or few; anyway they can be counted. We are dealing with erythematous lesions, with fairly sharp borders, that enlarge centrifugally; the mature lesions are 5-20 cm in size, with a red, sometimes brownish peripheral rim, while the central inflammation tends to disappear leaving a hypopigmented outcome. After years the single lesion regresses completely without residua, but usually new lesions appear with the same clinical course; so the disease is chronic, being able to last as in our case more than 10 years. Histological examination shows in the epidermis basket hyperkeratosis, normal granular layer, thinner or quadrangular epidermal ridges according to the evolutionary stage, vacuolar degeneration and keratinocyte necrosis exclusively or mainly at the level of the dermal base of the ridges, and, in the superficial dermis, lichenoid, polyclonal band infiltrate (1). (...).