Juvenile dermatomyositis, an inflammatory illness of unknown cause, primarily affects skin, muscle, and blood vessels. Affected children typically have characteristic skin lesions and muscle weakness. Characteristic dermatologic findings include periorbital and facial erythema often with edema; hyperkeratotic, red-to-pink papules over the knuckles of the hands, known as Gottron papules; and periungual telangiectasia, best seen with the aid of an ophthalmoscope or other form of magnification. The skin often demonstrates photosensitivity with the facial rash resembling a persistent sunburn. The butterfly pattern of the facial erythema may be mistaken for the malar blush of systemic lupus erythematosus.