Development of psoriatic lesions during acute and convalescent phases of Kawasaki disease.

A 7-month-old infant developed a discrete pustular rash confined to both soles during the acute phase of Kawasaki disease. Histological examination of a pustular lesion from the sole of a foot showed subcorneal neutrophilic microabscesses, psoriasiform acanthosis with a thin granular layer and mononuclear perivascular infiltrates in the upper dermis, consistent with psoriasis. Following the standard treatment with intravenous gamma globulin, the initial symptoms and signs of Kawasaki disease resolved completely. Eight weeks later, psoriasiform plaques appeared on both cheeks and on the extensor surfaces of the forearms and legs. Skin biopsy from one of these lesions revealed psoriasiform epidermal hyperplasia, focal parakeratosis and dilated papillary capillaries. The patient was treated with mild-potency topical steroids that resulted in rapid and complete resolution of the skin lesions. Concurrent association of psoriatic skin lesions and Kawasaki disease might not be incidental and could stem from a common pathogenetic mechanism induced by superantigens.