Brewer's asthma due to malt contamination

We describe a case of a 28 year old brewery worker who developed asthma whilst grinding malt. Lung function measurements demonstrated deterioration and improvement in lung function associated with work and absence from work. Inhalation challenge with ground malt from the brewery was positive but with ground malt from another source was negative suggesting a contaminant of the malt was responsible. Culture of the brewery malt showed heavy contamination with Aspergillus niger, but A. niger skin test was negative and aspergillus-specific IgG was not detected in the patients serum. Removal of the subject from the grinding room resulted in resolution of symptoms and normal lung function. We discuss the role of A. niger as an aetiological agent for occupational asthma with reference to the above case.