Amyopathic dermatomyositis in children: A diagnostic and therapeutic dilemma

Juvenile dermatomyositis is an inflammatory disease of unknown etiology tha t primarily affects skin and muscles. The pathognomonic Gottron's sign cons ists of symmetric macules and papules on the dorsal aspect of the interphal angeal joints and exterior areas of the big joints. A periorbital violaceou s (heliotrope) skin rash is also characteristic. There may be a discordance in time of presentation of the skin and muscle disease, and a small subset of patients apparently do not develop muscle disease at all. The absence o f muscle involvement is termed 'amyopathic dermatomyositis.' We describe two children who presented with the characteristic rash of juve nile dermatomyositis but with no clinical evidence of muscle involvement. O ne developed muscle weakness 3 years later. Neither patient had a full musc le work-up at the onset of the disease, which left questions about diagnose s and whether or not there may have been subtle muscle involvement. On the basis of our Literature review, the outcome of these patients is unc ertain, although it appears that myositis develops in many, maybe most, aff ected children. We suggest that in the absence of muscle disease, applicati on of sunscreen and administration of hydroxychloroquine sulfate may amelio rate the rash. More aggressive treatment will need to be given when muscle involvement can be demonstrated.