Type I wheat ingestion allergy: a model of masked allergy.

Type I wheat ingestion allergy is a special type of food allergy because the patient usually is not aware of his allergy. The unawareness comes from two reasons; one is that the clinical symptom appears not immediately after ingestion of wheat products but occurs sometime (30-60 min) later, and the other is that it may not appear if the patient does not exercise at this particular time. Therefore, the reaction does not always follow wheat ingestion. The study of enzymatically digested gluten antigens in the patients disclosed that the allergenicity to wheat was reinforced by peptic digestion but abolished by further tryptic digestion, indicating that allergen activity was most potent in the stomach. Anaphylaxis may occur in some patients after wheat ingestion and exercise. Therefore, in exercise-induced anaphylaxis without apparent allergy, one should consider wheat allergy.