Allergy is a hypersensitive disorder of the immune system. Allergic reactions occur to normally harmless environmental substances known as allergens; these reactions are acquired, predictable, and rapid. Strictly, allergy is one of four forms of hypersensitivity and is called type I (or immediate) hypersensitivity. It is characterized by excessive activation of certain white blood cells called mast cells and basophils by a type of antibody known as IgE, resulting in an extreme inflammatory response. Common allergic reactions include eczema, hives, hay fever,asthma attacks, food allergies, and reactions to the venom of stinging insects such as waspsand bees.
- The drug is widely used to control asthma attacks, but is now being linked to psychiatric problems in children and adolescents.
- PSAAI says that other than food allergy, some problems encountered after eating a specific food could be sourced from other kinds of reactions to food such as poisoning and food intolerance.