Incidence of pemphigus in Thrissur district, south India

Background: Pemphigus is a common autoimmune blistering disorder in India. However, there are no population based surveys from India available to study the prevalence of this disease. Aims: To estimate the incidence of pemphigus in Thrissur district, Kerala, South India. Methods: Questionnaire based survey was conducted among the practicing dermatologists of Trichur district between 1(st) January 2001 and 1(st) January 2002 to determine the incidence of pemphigus in the district. Results: Ten cases of pemphigus vulgaris, one case of pemphigus erythematosus, and two cases of pemphigus foliacious were diagnosed during the study period in a population of 2.9 million in Thrissur district. The average age of pemphigus vulgaris patients was 58 years in males [42 to 82 years] and 37 in females [25 to 57 years]. The average age of the two male pemphigus foliacious patients was 46 years [52 and 40 years] and the only pemphigus erythematosus patient was a 45 year-old female. Five cases of pemphigus vulgaris were investigated clinically histopathologically and by using direct immunofluorescence, while two were investigated clinically and histopathologically, two cases clinically, and one case clinically and with Tzanck smear. Two cases of pemphigus foliacious were diagnosed with the aid of direct immunofluorescence and the only case of pemphigus erythematosus was diagnosed with the aid of direct immunofluorescence. Pemphigus vulgaris was common among females. The incidence of pemphigus in Thrissur district is 4.4 per million. Conclusions: This study indicates that the incidence of pemphigus in Thrissur district is high in comparison to the available studies from Germany, France, and the North African country Tunisia.