Comparative epidemiology of pemphigus in Tunisia and France: unusual incidence of pemphigus foliaceus in young Tunisian women.

Recent studies have suggested that in Tunisia, pemphigus foliaceus is more frequent in young women than expected. To confirm these findings, we compared the incidence rates of pemphigus in Tunisia as a whole and in a large area of France. New cases of pemphigus were detected retrospectively from dermatology departments and pathology laboratories over a 6-year period and classified as pemphigus vulgaris or foliaceus according to the pathology. In France, the incidence rate was 1.7 cases per million per year (95% confidence interval 1.4 to 2.1). Pemphigus vulgaris accounted for 73% of all cases, incidence increased with age, and the female-to-male sex ratio was 1.2. The incidence rate was significantly higher in Tunisia than in France: 6.7 cases per million per year (95% confidence interval 5.8 to 7.7); pemphigus foliaceus was more frequent (61%), the female-to-male sex ratio was 4.1, and the incidence rate was higher in young women. The incidence rate was 15.5 cases per million per year for pemphigus foliaceus among women aged 25 to 34 years and was even higher in some rural areas. No case was observed among household members or in neonates, and only one case occurred in childhood. Thus, we confirmed that the epidemiology of pemphigus in Tunisia is unusual. High rates of pemphigus foliaceus among young people living in rural areas are reminiscent of Brazilian pemphigus. However, the absence of cases among genetically related household members and during childhood, and the large predominance of women, contrast with Brazilian pemphigus.