Gianotti-Crosti syndrome presenting as lichenoid dermatitis

Papular acrodermatitis of childhood (Gianotti-Crosti syndrome) is an uncomm on, self-limited disease characterized by an erythematous papular eruption symmetrically distributed on the face and limbs and mild lymphadenopathy, t hought to be of viral origin. The histopathologic findings are nonspecific and include focal parakeratosis, mild spongiosis, superficial perivascular infiltrate, papillary dermal edema, and extravasated red blood cells. Inter face changes with some basal vacuolization may be present, but are not a co nspicuous feature. We present a 21/2-year-old boy with multiple papules and plaques on the face and extremities and cervical lymphadenopathy. Histopat hologic analysis showed compact orthokeratosis, focal parakeratosis, hyperg ranulosis, psoriasiform epidermal hyperplasia, and a dense lichenoid lympho histiocytic infiltrate with extensive exocytosis of mononuclear cells. Immu noperoxidase staining with CD1a revealed clusters of Langerhans cells in th e epidermis and in the papillary dermis. In view of the clinical findings, a diagnosis of Gianotti-Crosti syndrome was made. Although there are a few reports describing a lichenoid pattern of infiltration in Gianotti-Crosti s yndrome, this histologic pattern is not widely known. This case is presente d to illustrate the fact that Gianotti-Crosti syndrome can present as liche noid dermatitis, and, especially in children, should be added to the differ ential diagnoses of lichenoid infiltrates.