Allergy – which comes from the Greek allos (strange) and ergos (activity) – is a defense reaction of the body against external substances that penetrate the body but do not cause a reaction in most people, as they are harmless. In allergy sufferers, when the immune system recognizes these substances as foreign, it tries to neutralize them using mechanisms that become harmful against the body itself , thus causing the symptoms of allergy. For some years it has been known that the antibody involved in allergic or hypersensitivity reactions is Immunoglobulin E , also known as reagin. The most common symptoms are runny noses, sneezing, itching, rashes, edema (swelling), and asthma.
The substances that most often cause allergic reactions ( allergens ) are pollen, dust mites (Dermatophagoides pteronyssus), mold spores, animal hair, certain foods, insect bites, and medications such as penicillin. But there are also others such as latex allergy or Anisakis allergy.
The first documented allergy case was that of Egypt's first pharaoh, Menes , who reportedly died of a bee sting in 2,640 BC. Currently, it is estimated that a quarter of people in developed countries experience an allergy.
