Contact allergy to aliphatic polyisocyanates based on hexamethylene-1,6-diisocyanate (HDI).
BACKGROUND
Aliphatic polyisocyanates based on hexamethylene 1,6-diisocyanate (HDI) are components of lacquers, coatings, and spray paints. They are mainly composed of HDI trimers, but also contain larger oligomers, and minute amounts of HDI monomers (<1%). HDI trimers occur as biuret, isocyanurate and asymmetrical types.


OBJECTIVE
We report on 4 patients with allergic contact dermatitis/contact allergy resulting from HDI-based polyisocyanates in polyurethane paints.


METHODS
The patients were examined at the Finnish Institute of Occupational Health in 2000-2009. The first two patients were diagnosed by testing with their own polyurethane hardeners and ingredients of the hardeners. In 2002, HDI isocyanurate (HDI-IC) trimer was added to our isocyanate series, and the last two patients were screened with the series.


RESULTS
Patient no. 1 was exposed and sensitized to HDI biuret trimer, patient no. 2 to HDI-IC trimer, and patient no. 4 to HDI asymmetrical trimer. Patient no. 3 was positive with HDI-IC trimer. He had been handling several paint hardeners containing HDI-based polyisocyanates, but the subtypes of the trimers remained unidentified. All 4 patients were negative with HDI monomer.


CONCLUSIONS
HDI trimers are novel contact allergens in workers who handle polyurethane paints. The allergic reactions cannot be explained by sensitization to HDI monomer.
Finnish Institute of Occupational Health (FIOH), Control of Hypersensitivity Diseases, Helsinki, Finland. kristiina.aalto-korte@ttl.fi
Kristiina
K
Aalto-Korte
Maria
M
Pesonen
Outi
O
Kuuliala
Kristiina
K
Alanko
Riitta
R
Jolanki
D000328:Adult; D003485:Cyanates / Q000633:toxicity; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000209:etiology*; D009783:Dermatitis, Occupational / Q000209:etiology*; D005260:Female; D006801:Humans; D017953:Isocyanates; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D010150:Paint / Q000633:toxicity*; D011140:Polyurethanes / Q000633:toxicity*
D003485:Cyanates; D017953:Isocyanates; D011140:Polyurethanes; C015262:1,6-hexamethylene diisocyanate