Formaldehyde allergy. Incidence and patch test problems

Abstract

Conflicting reports on formaldehyde allergy led us to analyze our clinical and patch test data. While patch-test positive formaldehyde allergy occurred in less than 5% of our eczematous patients, when present it was usually clinically significant. In three patients formaldehyde allergy caused garment contact dermatitis. Patch tests with formalin require critical evaluation as false-positive irritant responses may occur, especially if 4% or 5% formalin is used. The high incidence of so-called latent formaldehyde allergy found in some studies probably represents an artifact from misinterpretation of irritant reactions. The patch test with 2% formalin is a useful procedure in the investigation of contact dermatitis.