Bakers' asthma caused by alpha amylase.

Two bakers with bronchial asthma and two with rhinoconjunctivitis are described. Prick and RAST tests were positive with wheat flour in all of them, but the challenge test (nasal or bronchial) with wheat flour extract was positive only in one asthmatic baker. The prick test, RAST, and nasal or bronchial challenge done with alpha amylase extract (a glycolytic enzyme obtained from Aspergillus oryzae and used as a flour additive) were positive in all four patients. Our results support previous data indicating that alpha amylase used in bakeries is an important antigen that could cause respiratory allergy in bakers. It can function as sole causative allergen or in addition with other allergens used in the baking industry.