Is It Drug or Food Allergy? A Case Report

Sometimes allergic reactions caused by various food allergens often hidden in the composition of medications can mistakenly be diagnosed as drug allergies. Such reactions can especially be unexpected if antihistamines-virtually designed to treat allergy symptoms, are imitated. We present the case of a 37-year-old female patient with cutaneous allergic reaction initially diagnosed as drug allergy to desloratadine/aerius, a desloratadine-containing antihistamine medication. The diagnostic search began with the anamnestic data of the patient about an allergy to cooked corn in her childhood, current seasonal allergic rhinitis, and hand dermatitis probably related to her professional activity. Skin tests and additional laboratory examinations led to diagnosing corn/maize allergy manifested as both food (mainly) and pollen allergy. Besides, it was concluded that hand dermatitis also can becaused by cornstarch contained in medical gloves. Finally, based on the results of a drug challenge test performed with two desloratadine-containing medications–desloratadine/aerius containing cornstarch as an excipient and desloratadine/lordestinenot containing cornstarch, the causative significance of corn was confirmed. Thus, the initial diagnosis of drug allergy was changed to that of food allergy.