Recurrent photosensitive dermatitis preceding juvenile dermatomyositis.

The classic features of childhood dermatomyositis include muscle weakness, elevated muscle enzymes, and characteristic abnormal muscle biopsy and electromyography. Paramount to the diagnosis are cutaneous dermatoses that include a heliotrope rash and Gottron's papules. Rarely, a photo-sensitive dermatosis may occur. A recurrent photoexacerbated dermatoses can be an initial sign of occult childhood dermatomyositis.