Occupational asthma due to maleic anhydride.

Few reported cases of asthma due to maleic anhydride have been reported,'2 although there have been several cases due to other acid anhydrides.Our case is unique in that the patient was exposed to both maleic anhydride (MA) and phthalic anhydride (PA).He had a negative challenge test to PA but reacted positively to MA showing the absence of cross reactivity between the two anhydrides in his case.Case report A 34 year old man joined a factory manufacturing urea formaldehyde glue, expandable polystyrene, and alkyd and polyester resins in April 1988.In January 1990 he was transferred to the alkyd polyester section.His job as an assistant technician included super- vision of a process using various chemicals.He developed a cough, rhinitis, breathlessness, and wheezing about one month after working in this section.The symptoms developed within minutes of exposure to dust during the loading of chemicals into a reactor.This usually took place during the morning shift.He developed the symptoms only when loading was carried out during his shift.His symptoms worsened and in March 1990 he was admitted to hospital for an acute asthmatic attack.In April 1990 he was transferred to another job in the same section-the filling and packing of the final product (alkyd or polyester resin).He had complete relief of symptoms.On 31 May 1990 he helped to clear the inlet of the reactor, which was blocked.He was exposed to some dust from the reactor and immediately developed an acute asthmatic attack.He had no history of asthma but had a history of vasomotor rhinitis before joining the factory.There was no family history of atopy or asthma.He smoked 20 cigarettes a day and had been smoking for the past 15 years.