Peanut allergy:: the problem of hidden allergens

History: Three patients developed recurrent anaphylactic reactions after ingestion of different kinds of food (Asian food, chocolate products, bakery products). Investigations: In all three patients a severe peanut allergy was confirmed either by skin prick testing or serologically (specific IgE for peanut of CAP class 3,4 and 6 respectively). Peanut allergy in all patients explained the anaphylactic reactions due to ingestion of hidden peanut in the food. Treatment: Patients were told to avoid the allergen. Because accidental ingestion is frequent in peanut allergy, they were equipped with a document stating the severity of the allergy and emergency medication (antihistamines, oral steroids, adrenaline injector). Conclusions: Peanuts can be concealed in different kinds of food because they are cheap, rich in protein and are often used to change the viscosity of other foods. Especially the American and Asian cuisines use peanuts in a wide variety of recipes. Furthermore accidental ingestion can occur due to false or lacking declaration of peanuts in processed food. Patients with peanut allergy should be informed about these possibilities.