Ask The Expert
July 21, 2014
I continue to see Baker’s Asthma in Australia. Often, bakers are exposed to multiple allergens, not just wheat. Sometimes it is difficult to obtain details of all potential allergens. What is the minimum allergen work-up you recommend, both in skin testing, and allergen serology?
By Dr. Alexander Diaz Rodriguez
Baker’s asthma is a frequent occupational allergic disease caused mainly by inhalation of cereal flour, particularly wheat flour. It is considered one of the most common types of occupational asthma. Although wheat is the most commonly involved cereal, others (rye, barley, rice, maize, and oats) also play a role in baker’s asthma. Other allergens like soy, various enzyme additives (amylase, cellulose), storage and house dust mites, yeast and molds have also been involved.
In the work up for the diagnosis, it is recommended to include skin prick test to: storage and house dust mites (Acarus siro, Tyrophagus putrescentiae, Lepidoglyphus destructor, Dermatophagoides pteronyssinus, Dermatophagoides farinae), cereal (wheat, rye, barley, maize, oats, rice), soy, enzymes (amylase, cellulose), yeast, egg and fungi. Skin prick testing is commonly used to identify allergen sensitizations because it is safe, specific and more sensitive than most in vitro assays.
Most occupational allergens are not standardized, thus, in many cases; patients are provisionally tested with noncommercially available, laboratory-made skin test extracts. It is also possible to use in vitro tests, such as the radioallergosorbent test (RAST) or enzyme-linked immunoassay (ELISA), for the detection of allergen-specific IgE antibodies; however, skin tests are usually more sensitive for early detection of sensitization than in vitro tests.
Despite skin tests and determination of specific IgE antibodies are useful to assess the sensitization to occupational allergens, the demonstration of the link between the specific sensitization and work-related changes in lung function is mandatory for the diagnosis of Baker’s Asthma. Other important issues are occupational history and exposure documentation.
- Moscato G, Pala G, Barnig C, De Blay F, Del Giacco SR, Folletti I, Heffler E, Maestrelli P, Pauli G, Perfetti L, Quirce S, Sastre J, Siracusa A, Walusiak-Skorupa J, Gerth van Wjik R. EAACI consensus statement for investigation of work-related asthma in non-specialized centres. Allergy 2012; 67: 491–501.
- Salcedo G, Quirce S, Diaz-Perales A. Wheat Allergens Associated with Baker’s Asthma. J Investig Allergol Clin Immunol 2011; Vol. 21(2): 81-92.
- Alvarez Castello M, Leyva Marquez Y, Castro Almarales RL, et al. Sensitization to storage mites, wheat and yeast allergens in Cuban bakers. World Allergy Organ Journal. Volume 6 (Suppl 1); 2013.
- Quirce S. Sastre J. Disease Summaries. Diagnosis of Occupational Asthma. World Allergy Organization web page. Available at: http://www.worldallergy.org/professional/allergic_diseases_center/occupational_asthma/
Alexander Diaz Rodriguez, MD
Allergist, Professor of Immunology
WAO Occupational Allergy Committee Member
Note: Please read disclaimer. Ask the Expert is for licensed physicians only.