Erythema nodosum and kerion of the scalp.

Three children had pustular patches develop over the occipital areas of the scalp. Colonies of Trichophyton mentagrophytes grew on cultures with Sabouraud's dextrose agar with antibiotics. After a week of topical treatment with 1:10,000 potassium permanganate solution and oral treatment with griseofulvin, typical nodules of erythema nodosum appeared over the shins, ranging in diameter from 1 to 4 cm. Nodules on the legs resolved spontaneously within 12 days in the three children. Erythema nodosum occurring in patients with kerion may be interpreted as individual allergic hypersensitivity reactions as a result of the immune host response to allergenic products from the primary site of infection. This possibly may cause immune complexes that precipitate erythema nodosum.