Autoimmune skin disease among dermatology outpatients in Botswana: a retrospective review.

BACKGROUND: There is a paucity of data describing autoimmune skin diseases in sub-Saharan Africa and in HIV positive cohorts. We describe the incidence of autoimmune skin diseases in public dermatology clinics in Botswana.

METHODS: New patient records from public dermatology clinics were reviewed retrospectively for the period of September 2008 to December 2015. New diagnoses of cutaneous lupus erythematosus, systemic lupus erythematosus (SLE) with cutaneous involvement, dermatomyositis, systemic sclerosis, lichen sclerosus, bullous pemphigoid, pemphigus foliaceus, pemphigus vulgaris, and pemphigus vegetans were identified. Demographic data were recorded, and incidence was determined.

RESULTS: A total of 262 patients were diagnosed with autoimmune skin disease (4% of all new patients) with an incidence rate of 28.8 (per 1,000,000). Cutaneous lupus was the most common diagnosis with discoid lupus occurring most frequently (12.6). The incidence of systemic sclerosis (2.2), morphea (1.6), lichen sclerosus (1.5), SLE with cutaneous involvement (1.3) and dermatomyositis (1.2) was relatively lower. Bullous pemphigoid was the most common bullous disease (3.8). Pemphigus foliaceus (0.9), pemphigus vulgaris (0.6), and pemphigus vegetans (0.2) were observed at a lower rate. At least 19.8% of these patients were also HIV positive.

CONCLUSIONS: The incidence of autoimmune skin diseases in Botswana is lower compared to other published studies in other geographic areas, which may be reflective of a younger population, barriers to access, genetic differences, and a lack of comparative studies in sub-Saharan Africa. The hygiene hypothesis and helminth infections may also contribute to these differences. Further studies are needed to understand these disorders in this region.