Prospective study of clinical symptoms and skin test reactions in medical students exposed to formaldehyde gas.

Previous investigators have reported the occurrence of both allergic and non-allergic systemic complications due to exposure to formaldehyde gas. However, little is known about the pathogenic link between formaldehyde-induced clinical symptoms and patch test results, or about the long-term effects of formaldehyde exposure. In the present study, a questionnaire was administered to 143 medical students, and 60 of them were tested by patch test for formaldehyde at the beginning and end of a human anatomy laboratory course. Another group of 76 students who had finished the course 2-4 years previously were administered another questionnaire, and the patch test was carried out on 58 of them. The frequencies of skin irritation, eye soreness, lacrimation, eye fatigue, rhinorrhea, throat irritation, general fatigue and mood swings increased after repeated exposure. Two (3.3%) of 60 students became positive to 1% formaldehyde at the end of the anatomy course (one male with allergic hand dermatitis due to direct contact with formaldehyde, and one female with an atopic background with unbearable physical symptoms) while the remaining 58 showed a negative reaction throughout the study period. The vast majority of students complained of various non-allergic, physical symptoms, and recovered from such symptoms without subsequent complications. No progression to multiple chemical sensitivity was found. Students with an episode of atopic dermatitis and allergic rhinitis were susceptible to formaldehyde exposure, and developed mucocutaneous symptoms, probably due to the impaired barrier function and remodeling of the skin and mucosa.