Pemphigus and associated environmental factors: a case-control study.

Background: Recent reports have revealed the relatively high incidence of pemphigus in Iran. Occupational exposure and personal habits have been suggested to play a role in the aetiopathogenesis of this life-threatening disease.

Aim: In order to analyse the association of environmental factors with pemphigus, we conducted a case-control study to evaluate the possible role of smoking, pesticide exposure and hormonal factors in Iran.

Methods: This study was conducted in Iran using a structured questionnaire. Questions included information on patients' smoking habits, occupational exposure to pesticides, use of oral contraception (OC) and number of pregnancies.

Results: We enrolled 210 patients with pemphigus and 205 control subjects. Fewer of patients with pemphigus (17.1%) reported a current or past history of smoking, which was statistically different from the control group (27.3% smokers). The duration of smoking and the number of cigarettes smoked daily was also significantly lower in patients. Although OC use was significantly higher in women with pemphigus, the mean number of pregnancies was not different between the two groups. Occupational exposure to pesticides was significantly higher in patients with pemphigus (14.8%) than in controls (5.4%); patients with pemphigus were exposed to pesticides three times more often than were healthy subjects.

Conclusion: As a positive history of smoking was lower in patients with pemphigus compared with healthy subjects, it seems that smoking is a protective factor in pemphigus. This should encourage further investigations, searching for novel therapies. If pesticides and OC are confirmed as triggering factors, their cessation might reduce the need for pharmacological therapy.