Sensitization to xylanolytic enzymes: an underestimated health hazard among bakers

The most important occupational allergens in baking include flour and enzymes, especially α-amylase. Although xylanolytic enzymes have previously been described as sensitizers, they may be overlooked during assessment of bakery workers with work-related symptoms.

To report a case of a baker who suffered from work-related respiratory, ocular and skin symptoms as a consequence of sensitization to xylanolytic enzymes.

Physical examination, chest X-ray, routine laboratory tests, skin prick tests (SPTs) with common and occupational allergens (wheat, pearl, rye, corn and oat flours, α-amylase, bakery adjuvants) and spirometric measurements, as well as assessments by a laryngologist, dermatologist and ophthalmologist were performed. Specific IgE (sIgE) to occupational agents were evaluated for flours, α-amylase, xylanase, cellulose and glucoamylase. Specific inhalation challenges (SICs) with flours and bakery adjuvants were carried out.

Hypersensitivity to Aspergillus moulds, flours and α-amylase was confirmed in SPTs; however, SIC with those agents gave a negative result. Further investigation revealed the presence of sIgE to xylanolytic enzymes. During SIC with bakery adjuvants, allergic skin, ocular and respiratory symptoms occurred and were confirmed by objective assessment.

In the assessment of work-related allergic symptoms in bakers, sensitization to xylanolytic enzymes should be considered. Completion of diagnostic procedures having excluded asthma and rhino-conjunctivitis related to flour hypersensitivity might result in a false-negative assessment.