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.