Formaldehyde--induced bronchial asthma--does it really exist?

These studies try to explain if there is a correlation between exposure to formaldehyde (FM) and bronchospastic reactions. 367 workers were examined in our study. They were aged 23 to 52. They had been exposed occupationally to FM at concentration not exceeding 0.5 mg/m3. All subjects suffered from respiratory symptoms; 14 had chronic bronchitis, 2 bronchial asthma. A history was taken and spirometry performed (peak expiratory flow (PEF)) with use of a single blind crossover method, in a three-day clinical observation. All subjects were provoked with histamine (PC20). Skin prick tests with common allergens, a patch test with FM and formaldehyde-specific IgE antibodies assay were performed. There were no significant differences in the respiratory parameters during the three-day clinical observation. Two subjects were supposed to have bronchial asthma induced by FM, but for lack of differences in respiratory parameters the occupational background of their asthma was excluded. None of the subjects complained of significant irritant symptoms. On the basis of our results one may doubt that FM is capable of acting as a respiratory sensitizer.