Background: Although insect and arthropod contamination of certain foods has been recognized for many years, allergic manifestations caused by ingestion of mite allergens have only rarely been reported.
Objective: The purpose of this study is to present clinical observations in patients who experienced acute anaphylaxis after eating mite-contaminated foods.
Methods: Thirty atopic subjects who were first seen with systemic anaphylaxis precipitated by the ingestion of wheat-containing foods underwent skin prick tests with inhalant and food extracts, as well as with uncontaminated and mite-contaminated wheat flour. Flour samples were examined microscopically for identification and counting of mites. Der p 1 and Der f 1 levels were quantitated by using immunochemical methods.
Results: The most common symptoms were breathlessness, angioedema, wheezing, and rhinorrhea, which started between 10 and 240 minutes after eating. Abundant mites were present in the flour obtained from 28 patients; Suidasia spp. mites were found in grated bread from the other two patients. Positive prick test responses to Dermatophagoides farinae-and mite-contaminated flour and negative skin test responses to wheat extract, other food extracts, and uncontaminated wheat flour were found in all patients. Skin test responses were positive in volunteers with mite allergy even after heating the mite-contaminated flour at 100 degrees C. Screening of 35 unselected flour samples demonstrated the presence of mites in 13 of them (37.1%).
Conclusions: Systemic anaphylaxis can occur after the ingestion of heated or unheated mite-contaminated foods. This problem may be more prevalent in tropical and subtropical countries than previously recognized.