Background

  • Oral mite anaphylaxis (OMA) is an IgE-mediated reaction to ingested dust mites (often contaminating wheat flour), and may be a hidden cause of anaphylaxis
    • It has been reported that milder immediate reactions such as isolated cutaneous symptoms (urticaria, facial AE) or exacerbation of pre-existing respiratory disease (rhinitis, asthma) may occur after mite ingestion
  • Mites responsible for OMA include domestic species (D. pteronyssinus, D. farinae, and Blomia tropicalis), as well as storage mites (S. medanensis, Aleuroglyphus ovatus, Lepidoglyphus destructor, Tyrophagus putrescientiae, Tyreophagus entomophagus, and Blomia freemani)
  • Risk factors include:
    • Previous atopic disease
    • Mite sensitization
    • NSAID hypersensitivity
    • Ingestion of pancakes or other meals containing wheat flour
    • Ingestion of more than 1 mg of mite allergen (>500 mites per gram of flour)


Diagnosis

  • OMA can be confirmed in patients who meet the following criteria:
    1. Compatible symptoms occurring after eating foods prepared with wheat flour
    2. Previous history of rhinitis, asthma, atopic eczema, or food allergy
    3. Demonstration of mite-specific IgE (SPT or sIgE)
    4. Positive skin test response induced by an extract of the incriminated flour
    5. Negative skin test response to commercial wheat extract and to an extract of uncontaminated flour
    6. Tolerance to other foods made with uncontaminated wheat flour
    7. Microscopic identification of mites in the suspected flour
    8. Presence of mite allergens in the flour, as demonstrated by means of immunoassay
    9. Aspirin/NSAID hypersensitivity (a risk factor for OMA)

References