Incidence of pemphigus vulgaris exceeds that of pemphigus foliaceus in a region where pemphigus foliaceus is endemic: analysis of a 21-year historical series.

Background: There are two main clinical subsets of pemphigus: pemphigus vulgaris and pemphigus foliaceus. Clinical and epidemiological changes related to both types of pemphigus have been observed in the last years.

Objectives: To analyze a 21-year historical case series of pemphigus vulgaris and pemphigus foliaceus in the northeast region of the state of Sao Paulo, where pemphigus foliaceus is endemic.

Methods: In this descriptive study, data related to annual incidence and age of onset of symptoms compatible with pemphigus vulgaris or pemphigus foliaceus were analyzed, comparing both forms, in the period from 1988 to 2008.

Results: The overall results cover a period of 21 years, with 103 cases of pemphigus vulgaris and 163 cases of pemphigus foliaceus. An evaluation of the trend lines regarding incidence has shown that pemphigus foliaceus is decreasing while pemphigus vulgaris is increasing. There was great variation in the age ranges, with persistence of the minimum range, from 10 to 20 years old, for pemphigus foliaceus (mean age = 32.1 years old), and clear downward in the minimum age for pemphigus vulgaris (mean age = 41.5 years old), especially from the middle of the first decade of the total period studied.

Conclusion: The incidence of pemphigus vulgaris has been exceeding that of pemphigus foliaceus since 1998. The results of this case series comprehending 21 years corroborate the change in the epidemiology of both clinical forms of pemphigus in Brazil, raising new hypotheses for their etiology and pathogenesis.