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House dust mites (HDM) as a cause of food allergy

If you think house dust mite (HDM) allergies and food allergies are separate, think again! An allergen from the mite has been found in poorly stored wheat flour and in the human gut. Doctors know that infested flour can cause a rare form of severe allergic reaction, but are unsure of what effects the allergen has on the gut. World Allergy Organisation advice is to keep opened flour in the fridge or freezer to prevent HDM infestation.
Poorly stored opened wheat or corn flour, infested with house dust mites, and then cooked can cause a dangerous allergic reaction known as food anaphylaxis. The World Allergy Organisation refer to the reaction as Pancake Syndrome, and include it in their 2015 evidence based Guidelines on Anaphylaxis.

Pancake Syndrome, also known as Oral Mite Anaphylaxis (OMA), is a severe allergic reaction that can happen shortly after eating cooked foods made with mite-contaminated flour. At risk are those patients already allergic to storage or house dust mites and living in areas with tropical or sub tropical environments. Please note, many poorly ventilated kitchens around the world can fit into this category.

Reports of pancake syndrome or OMA are relatively rare, however allergists are concerned that many food related severe allergic reactions classed as 'of unknown origin' may be caused by a mite allergen that is known to be resistant to heat. Most severe reactions are reported when products are infested after processing and during storage at home. There is also the possibility however, of infestation during the food supply chain.

Below is a stark warning concerning OMA that came from UK's Anaphylaxis Campaign.

'A study of cereal-based foodstuffs has found that over a third of samples contained storage mites. Ingestion represents another route contributing to the overall allergen load. The numbers of mites found were low but some were probably alive immediately before analysis and one of the most infested samples was an item of baby food. Since the risk of sensitisation is greater early in life, work is urgently needed to quantify the threat to health'.

Note: A variety of this condition can occur during physical exercise (dust mite ingestion associated exercise induced anaphylaxis) associated with a sensitivity to aspirin.

The major house dust mite allergen Der p1, an active digestive enzyme, has recently been identified in the gastrointestinal tract of the humans. The significance of its presence is currently being investigated, but this fact adds weight to warnings of Pan Cake Syndrome or OMA.


  1. Food Allergen Labelling and Consumer Protection Act of 2004 (Public Law 108-282, Title II), US Department of Health and Human Services
  2. Pancake Syndrome (Oral Mite Anaphylaxis). Snchez-Borges et al (May 2009). 'World Allergy Organization' Journal. Volume 2, Issue 5, pp 91-96. doi: 10.1097/WOX.0b013e3181a0db50
  3. 'The importance of storage mite allergens in occupational and domestic' Chambers et al (1999). environments. 'Proceedings of the 3rd Inter. Conference on Urban Pests.'
  4. Anaphylaxis from ingestion of mites: Pancake anaphylaxis. Sanchez- Borges M, Suarez Chacon R, Capriles-Hulett A, Caballero-Fonseca E., 'J. Allergy Clin. Immunol.', 2013: 131 (1): 31-35
  5. Presence of commensal house dust mite allergen in human gastrointestinal tract: a potential contributor to intestinal barrier dysfunction, Tulic M.K. et al, Gut, 65, (5) p757-766
  6. 'Dust Mites', Matthew J. Colloff, 2009, CSIRO PUBLISHING, Collingwood, Australia; ISBN 978-0-6430-6589-5
  7. 'Update of the Evidence Base: World Allergy Organisation Anaphylaxis Guidelines', 'WAO Journal', position article and guidelines, F.ER Simons et al, Web Base Open Access2015