• allergy;
  • anaphylaxis;
  • corn flour;
  • dust mites;
  • food allergy;
  • storage mites

It is known that anaphylaxis can be induced in some mite-sensitized patients by the ingestion of foods contaminated by mites. These patients usually have current atopic disease, and most of them present acetylsalicylic acid sensitivity. House-dust mites and storage mites can precipitate these episodes. Wheat flour is the major source of mite allergens related to these cases. Here, we report a case of anaphylaxis possibly induced by the ingestion of corn flour contaminated with mites.

An 18-year-old woman developed nausea, abdominal cramps, wheezing, cough, dyspnea, and urticaria/angioedema a few minutes after eating polenta, a dish prepared with cooked corn flour. In hospital, she received subcutaneous epinephrine, intravenous hydrocortisone, and intramuscular antihistamine. The symptoms gradually subsided and she was discharged 6 h later.

She was interviewed 5 days after the anaphylactic episode. She denied taking any drugs or other foods in the 6 h before the episode. She had a history of mild symptoms of perennial rhinitis, and in the past she had suffered an episode of urticaria/angioedema induced by acetylsalicylic acid. It is noteworthy that 2 years before, she had experienced a milder episode of anaphylaxis of unknown cause. She now remembered that the symptoms had also begun minutes after she ate food prepared with corn flour, which seems to have been the trigger in both episodes.

Allergic sensitization was assessed by skin prick tests with foods and common inhalant allergens. Dermatophagoides pteronyssinus and Blomia tropicalis serum specific IgE were determined. Skin tests gave negative results to common foods, including corn flour, but the patient showed strong reactions to mite allergens (Table 1). In the absence of any possible trigger, we suspected anaphylaxis induced by mite-contaminated food. We examined a sample of the corn flour used in her home and found a total of 36 mites/g of corn flour, identified as Tyrophagus putrescentiae (11/36),D. pteronyssinus (8/36), D. farinae (5/36), and others (12/36). Analysis of marketed flour of the same brand gave negative results. Levels of the Dermatophagoides mite allergens Der p 1, Der f 1, and group 2, and of B. tropicalis allergen Blo t 5, assayed by mAb-based ELISA (1), were undetectable in extracts made from samples of corn flour.

Table 1.  Allergic evaluation
IgE determinations
 Total serum IgE: 334 IU/ml
 D. pteronyssinus IgE: 11.9 IU/ml
 B. tropicalis IgE: >17.5 IU/ml
Skin test results (mean wheal and flare in mm)
 D. pteronyssinus: 4×15 mm
 D. farinae: 5×15 mm
 B. tropicalis: 7.5×25 mm
 T. putrescentiae: 4×10 mm
 Histamine: 3×12 mm
 Corn flour: negative

Erben et al. (2), Matsumoto et al. (3), Blanco et al. (4), and Sanchez-Borges et al. (5) have all reported on anaphylaxis caused by mite-contaminated food. All the patients were atopics sensitized to mite allergens, and anaphylaxis was precipitated briefly after the ingestion of contaminated foods. Concomitant ASA intolerance was also reported among these patients. These findings indicate that mite allergenicity persists despite the cooking process. In most of these reports, the major source of mite allergens was wheat flour. Our case supports the hypothesis that anaphylaxis may be induced by corn flour contaminated by mites. We were unable to identify any other possible causes of the reaction. In addition, our patient was strongly sensitized to mite allergens, and the corn flour containing mites was the only food ingested within the 6 h preceding the episode. Our findings also indicate that this association must be considered in idiopathic or unexplained anaphylaxis in atopic patients.


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  2. References
  • 1
    Arruda LK, Rizzo MC, Chapman MD, et al. Exposure and sensitization to dust mite allergens among asthmatic children in São Paulo, Brazil. Clin Exp Allergy 1991;21:433439.
  • 2
    Erben AM, Rodriguez JL, McCullough J, Ownby DR. Anaphylaxis after ingestion of beignets contaminated with Dermato-phagoides farinae. J Allergy Clin Immunol 1993;92:846849.
  • 3
    Matsumoto T, Hisano T, Hamaguchi M, Miike T. Systemic anaphylaxis after eating storage-mite-contaminated food. In Arch Allergy Immunol 1996;109:197200.
  • 4
    Blanco C, Quiralte J, Castillo R, et al. Anaphylaxis after ingestion of wheat flour contaminated with mites. J Allergy Clin Immunol 1997;99:308313.
  • 5
    Sanchez-Borges M, Capriles-Hulett A, Fernandez-Caldas E, et al. Mite-contaminated foods as a cause of anaphylaxis. J Allergy Clin Immunol 1997;99:738743.
  1. A severe reaction after ingestion of mite-contaminated flour.