Fundamentals of Allergy app for iPhone and iPad

Allergies, also known as allergic diseases, are a number of conditions caused by hypersensitivity of the immune system to something in the environment that usually causes little problem in most people.These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, runny nose, shortness of breath, or swelling. Food intolerances and food poisoning are separate conditions.

Common allergens include pollen and food. Metals and other substances may also cause problems.Food, insect stings, and medications are common causes of severe reactions. Their development is due to both genetic and environmental factors.The underlying mechanism involves immunoglobulin E antibodies (IgE), part of the bodys immune system, binding to an allergen and then to a receptor on mast cells or basophils where it triggers the release of inflammatory chemicals such as histamine.Diagnosis is typically based on a persons medical history. Further testing of the skin or blood may be useful in certain cases. Positive tests, however, may not mean there is a significant allergy to the substance in question.