Allergic diseases such as anaphylaxis, urticaria and angioedema can occur due to exposure to certain foods, drugs, insect venoms and certain unknown triggers. Detailed evaluation of these patients involves a thorough history of all the preceding events, allergy skin testing, provocative challenge testing, and other ancillary blood investigations.

Some of these patients may require Desensitization therapy, especially if the triggering agent is a common and essential drug. Usually food allergies are overestimated, and patients generally avoid a lot of food for fear of allergy. Careful evaluation could restore most foods to their table if an allergy is disproved