Asthma from hair straightening treatment containing formaldehyde: Two cases and a review of the literature.

We report two cases of formaldehyde-containing hair straighteners causing new onset asthma. Formaldehyde has been reported to cause asthma in other settings. The purpose of this article is to examine two cases of asthma in hairdressers exposed to hair smoothing products and to review the relevant literature on formaldehyde exposure and asthma. The results indicated that both subjects developed asthma from repeated occupational exposure to formaldehyde during hair treatments. Both subjects became unable to tolerate hair straightening activity in their vicinity. Formaldehyde-containing hair smoothing products are sources of exposure, and the risk of developing asthma is high in salon settings where hair straightening is performed using formaldehyde.