Introduction: Dermatomyositis (DM) is rarely reported in black African. We report a retrospective study of epidemiological, clinical and evolutive aspects of dermatomyositis observed from 1983 to 2001 in dermatological department of Senegal.
Materials and method: The diagnosis of D M was a ccepted when patients proved to fulfil Bohan and Peter's diagnostic criteria. We had recruited 56 African black patients of average age 34.5 years and of sex-ratio (M/F) 0.27.
Results: The first clinical manifestation was cutaneous in 94% of cases. Dermatoligical signs were dominated bye rythema (77%), characterized by zebra-like aspect on extension faces of limbs. The erythema was pruriginous in 45% of cases. The others clinical manifestations were: muscular (86%), a rticular (60%), cardiac (34%), broncho-pulmonary (30.4%), digestive (30%), Raynaud's phenomena (20%) and ocular (7%). Muscular enzymes were increased in 95% for lacticodeshydrogenase and 71% for creatininine phosphokinase. Electromyography (in 25 cases), revealed a myogenic tracing in all cases, associated in 22 cases with a decreasing speed of the peripheral nervous conduction. Muscular biopsy made in 3 patients showed specific signs of DM and in one case, those were associated to a perivascular infiltration in the muscles and nerves with axonal nervous degeneration images. Dermatomyositis were p araneoplasic in 6 cases and the cancers were genital in all cases. The evolution after corticotherapy was favourable in 59% of cases. The cases of death (14 cases) were caused by the associated cancer (6 cases), repirator distress (4 cases) and infectious's complication of corticotherapy (4 cases). The relapses (16%) were secondary to treatement's interruption.
Conclusion: DM in Senegal affects young people with zebra-like erythema, often scratched and frequently associated with peripheral neuropathy. Genital cancers predomined in paraneoplasic forms.