An allergy refers to an exaggerated reaction by the immune system in response to exposure to certain foreign substances. The response is exaggerated because these foreign substances are normally seen by the body as harmless in nonallergic individuals and do not cause a response in them. In allergic individuals, the body recognizes the foreign substance, and the allergic part of the immune system generates a response.
The most common allergic diseases are nasal allergies, eye allergies, allergic asthma, hives, and food allergies.
Examples of allergens include pollens, dust mites, molds, animal proteins, foods, and medications.
Symptoms of an Allergy
- shortness of breath
- runny nose and eyes
- pain over the sinuses
- skin rashes (nettle rashes or hives)
- swelling of the lips or face
- itching eyes, ears, lips, throat and roof of the mouth
- abdominal cramps and diarrhoea