Evaluation of a worker with possible formaldehyde-induced asthma

Background: We describe the evaluation of a worker with clinical symptoms compatible with bronchospasm caused by formaldehyde exposure. Methods: The worker was evaluated by means of enzyme-linked immunosorbent assay, cutaneous tests, and methacholine and formaldehyde inhalation challenges. The worker's serum was injected intradermally into the skin of a normal rhesus monkey to determine whether hypersensitivity could be transferred from human to primate. Results: An enzyme-linked immunosorbent assay showed that the worker had positive IgE and IgG titers to formaldehyde-human serum albumin. The worker had a positive cutaneous test for formaldehyde-human serum albumin, and this cutaneous reactivity was transferred to a rhesus monkey through the worker's serum. The worker had a negative methacholine challenge at 25 mg/ml and negative formaldehyde inhalation challenges at 0.3, 1, 3, and 5 ppm for 20 minutes. It is possible that the worker would have had a positive result if a higher concentration of F were used for the challenge, but it is more probable that the worker's symptoms were not caused by immunologically mediated asthma. We have studied individuals exposed to formaldehyde, their clinical syndromes, and serologic results for a decade. This worker is the one subject with the most compatible history and immunology, but the worker had a negative challenge. Conclusion: Immunologically mediated asthma caused by formaldehyde is extremely rare, if it exists at all.