[Dermatomyositis and polymyositis: 21 cases in Senegal]

Dermatopolymyositis (DPM) is a term describing a group of disorders comprising multiple distinct entities depending on interactions between genetic and environmental factor. There is a paucity of studies on DPM in black Africa. The purpose of this report is to describe epidemiological, clinical, laboratory and therapeutic aspects of dermatomyositis (DM) and polymyositis (PM) observed at the Principal Hospital in Dakar, Senegal. A retrospective review as conducted of patients hospitalized for DM and PM in Medical Departments of Principal Hospital. Diagnosis of DRM was based on the criteria of Bohan and Peter's in all cases. A series of 21 black African patients was compiled including 15 with DM and 6 with PM. Mean age was 52 years and the M/F sex ratio was 0.6. The mean delay for diagnosis was 6 weeks (range, 3 to 12 weeks). Initial signs were dermatological in 12 patients, pulmonary in one and muscular in the remaining cases. The most common dermatological sign was erythema characterized by a zebra-like aspect on the extended limbs. Erythema was frequently pruriginous with a flagellate aspect on the back. Muscular signs were observed in 18 patients and included pharyngeal manifestations in 10 patients. Amyopathic DM was not observed. Cardiac abnormalities included tachycardia (4 cases), AVB (1), ischemic lesion (1), relaxation disturbances (4), pericardial effusion (3), myocarditis (2) and pulmonary hypertension (1). The most common pulmonary manifestation was interstitial lung disease observed in 6 patients. Gastrointestinal signs were noted in 9 patients including endoscopic evidence of superficial erosion in 4 cases. Electromyography (EMG) tracings revealed myogenic disease in 14 cases including 2 associated with reduced peripheral nervous conduction speed. Severe lymphopenia was observed in 3 patients but HIV serology was negative in all cases. Paraneoplasic DM was observed in 3 cases. Death occurred in 5 cases due to the cancer-related, pulmonary and infectious complications. Based on the findings of this study, the three main features of DM and PM in Senegal are flagellated and often pruriginous erythema, cardiac and interstitial lung disease, and peripheral neural involvement.