Acid anhydrides are low-molecular weight chemicals known to cause respiratory irritancy and
allergy. Skin
allergy has on rare occasions been reported. A total of 3 subjects with occupational exposure to methylhexahydrophthalic
anhydride (MHHPA) and
hexahydrophthalic anhydride (HHPA) from an
epoxy resin system were studied to evaluate the nature of their reported skin and nose complaints (work-related anamnesis, specific
IgE, contact
urticaria examinations, and ambient monitoring). Using a Pharmacia CAP system with a HHPA
human serum albumin conjugate, specific
IgE antibody was detected in serum from 1 (33.3%) out of the 3 workers. One unsensitized worker displayed nasal
pain and
rhinorrhea only when loading liquid
epoxy resins into the pouring-machine (2.2 mg MHHPA/m3 and 1.2 mg HHPA/m3), probably being an
irritant reaction. Two workers had work-related symptoms at relatively low levels of exposure (geometric mean 32-103 microg MHHPA/m3 and 18-59 microg HHPA/m3); one complained of only
rhinitis, and the other was sensitized against HHPA and displayed both
rhinitis and contact
urticaria (the face and neck). The worker's skin symptoms were evidently due to airborne contact, since she had not had any skin contact with liquid
epoxy resin or mixtures of MHHPA and HHPA. These
urticaria symptoms were confirmed by a 20-min closed patch test for MHHPA, but not by that for HHPA. The causative agent was considered to be MHHPA, although the specific
IgE determination to MHHPA was not performed.