CD30 Occupational contact urticaria to fungal alpha-amylase in a bakery worker

Abstract

Enzymes are widely used in the food and drinks industry. Fungal alpha-amylase is commonly added to flour and is a well-­recognized cause of baker’s asthma. Its potential to cause skin disease is much less recognized and reported. A 48-year-old bakery worker presented with a 3-month history of an intensely pruritic, urticarial rash occurring within 20–30 min of entering his workplace. The rash involved exposed sites on his hands, forearms and face. His symptoms resolved over 1–2 h after leaving the workplace. He had a background of atopy. He had worked in the bakery industry for > 20 years and had not experienced similar skin problems previously. In his current employment, he handled a number of flours and fungal alpha-amylase, which was commonly added to flour to improve the quality of the bread. A type I hypersensitivity was suspected. He underwent prick testing with positive and negative controls and with samples of the flours he handled, some of which contained fungal alpha-amylase, and to fungal alpha-amylase alone. Weal diameters for the positive control, flour-containing fungal alpha-amylase and fungal alpha-amylase alone were 5 mm, 7 mm and 10 mm, respectively. There was no weal formation to the negative control and the flours that did not contain fungal alpha-amylase. A diagnosis of type I hypersensitivity to fungal alpha-amylase was confirmed as the cause of his occupational contact urticaria. Patch testing to the British standard series, bakery series and samples of the flours and fungal alpha-amylase (as is) was negative, excluding a type IV hypersensitivity reaction. Allergen substitution was not commercially viable. He was redeployed to an area with no fungal alpha-amylase exposure and his skin problems resolved. This case highlights the potential for type I hypersensitivity to noncereal components in flour in the bakery industry.