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Fig. 35.4 Dermatomyositis. A, Facial erythema and heliotrope sign. B, Classic hand lesions and Gottron’s papules on the knuckles. |
The classic eruption of dermatomyositis is a reddish-purple erythema involving the face, typically the eyelids (heliotrope sign). The rash may be faint or quite inflamed and edematous (Fig. 35-4A).
In addition to the facial rash, lesions on the scalp, neck, upper trunk, and extensor extremities are common. As the lesions mature, scaling and atrophy may develop. The erythema on the hands occurs over the knuckles rather than over the phalanges, as is typical of lupus erythematosus. Cuticular telangiectasias can be seen in both lupus erythematosus and dermatomyositis. Frequently, flat-topped, red-to-violaceous papules known as
Gottron’s papules develop over the knuckles of patients with dermatomyositis (Fig. 35-4B).
The skin lesions of dermatomyositis may precede clinical or laboratory evidence by weeks, months, or years. A few patients may never develop muscle dysfunction. The skin lesions are notoriously resistant to topical steroid therapy.