Erythromelalgia associated with dermatomyositis: A case series

Dermatomyositis is a multisystem autoimmune connective tissue disease that can manifest with proximal muscle weakness, interstitial lung disease, and characteristic skin findings such as erythema and papules over the dorsal joints of the hand, periungual changes, heliotrope rash, and pruritic erythematous inflammation of the chest, back, arms, legs, and scalp. Erythromelalgia is a clinical diagnosis characterized by swelling, erythema, and burning pain, typically of the extremities and often triggered by heat or exertion. It can be classified as primary, due to genetic mutations, or secondary, associated with myeloproliferative, vascular, musculoskeletal, or neurologic disease.1 There have been reports of biopsies of erythromelalgia having some features of connective tissue disease.2,3 There are also reports of erythromelalgia associated with systemic lupus erythematosus and rheumatoid arthritis, two autoimmune connective tissue diseases.4 Here, we present two cases of erythromelalgia associated with dermatomyositis, which, to our knowledge, has not been reported in the literature to date. Case 1 An 81-year-old woman with a history of treated breast cancer presented to the dermatology clinic for evaluation of swelling and discoloration of her bilateral hands and feet of approximately 10 years' duration associated with heat intolerance. She had been seen by numerous vascular and lymphedema specialists over the years with the ultimate conclusion that her swelling was not associated with a vascular etiology. The patient noticed improvement of her symptoms when she was exposed to air conditioning or cold water. At presentation, she also reported shortness of breath, a burning sensation on her feet and scalp, subjective proximal muscle weakness, dysphagia, and weight gain. Her physical examination was notable for periungual telangiectasias, scale, and erythema on the V of her neck area, her extensor arms, and around her eyes (Fig 1). She believed that the erythema on the V of her neck area started 30 years ago, indicating the possibility that she had had potentially undiagnosed amyopathic dermatomyositis (DM) for years before her diagnosis of erythromelalgia. The patient's basic laboratory workup and immunologic studies were unrevealing, and a myositis panel was negative. Muscle magnetic resonance imaging and electromyography were not performed because of the absence of muscle pain or objective weakness on physical examination. Two skin biopsy specimens from the upper portion of the arm and the dorsal surface of the hand showed interface dermatitis (Fig 2), consistent with a diagnosis of DM based on clinicopathologic correlation with typical features of DM (as opposed to lupus, drug reaction, viral exanthem, lichen planus, or graft versus host disease). Pulmonary function testing showed an obstructive pattern with decreased carbon monoxide diffusion in the lung (62%), and chest computed tomography (CT) showed stable interstitial lung changes. The malignancy workup (including age-appropriate screening and CT of the chest, abdomen, and pelvis) was negative. The patient has had some relief from the burning sensation on her feet from topical 5% lidocaine and petroleum jelly. Because of shared decision-making and risk-benefit analysis, the patient has not started immunosuppressive therapy for her DM, but she is being followed closely. Open in a separate window Fig 1 Patient 1. Swelling and erythema on bilateral hands and feet.