Occupational asthma due to hexahydrophthalic anhydride: a case report.

Hexahydrophthalic anhydride (HHPA) belongs to the family of acid anhydrides, the members of which are reactive organic chemicals of low molecular weight widely used in alkyd and epoxy resins. The major toxic effects ofthe acid anhydrides are mucosal and skin irritation and respiratory hypersensitivity, particularly asthma. Most of the reported cases of asthma caused by acid anhydrides were due to phthalic anhydride. Cases of asthma caused by tetrachlorophthalic anhydride, himic anhydride, maleic anhydride, and pyromellitic dianhydride have also been reported.' Although HHPA has been implicated as a cause ofasthma in a study by Moller et al, this was based on clinical histories obtained from four out of 27 workers exposed to HHPA and the finding of specific IgE to HHPA in 44% of these exposed workers.2 In none of these cases was the diagnosis confirmed by specific challenge testing. We report a case of asthma induced by occupational exposure to HHPA who showed a bronchoconstrictive response to specific inhalation challenge with HHPA. To our knowledge, this is the first such reported case.