Possible mechanisms of formaldehyde-induced discomfort in the upper airways

Occupational exposure to formaldehyde often causes nasal discomfort. The objective of this study was to determine whether chronic exposure to formaldehyde causes annoying symptoms by direct irritation and whether it affects all exposed people (through hyperreactivity in atopic persons, through formaldehyde-induced hyperreactivity also in nonatopic persons, or through an immunologically mediated, immediate type 1 reaction to formaldehyde itself). It was found that about 50% of the studied population of 66 workers occupationally exposed to formaldehyde during formaldehyde production experienced nasal discomfort through hyperreactivity. Atopics were not significantly overrepresented among the persons with occupational nasal symptoms. Two workers with isolated occupational nasal discomfort, and sensitized by long-term inhalation, had a positive radioallergosorbent test for formaldehyde. The conclusion was reached that exposure to formaldehyde should be minimized as much as possible for all people, not only for atopic persons.