An allergy is the immune system’s response to what it perceives as a threat from a foreign substance such as a food item, pollen or an animal. When this substance, known as an allergen, enters your body, the immune system releases histamines which cause a series of physical reactions, including swelling. The swelling can occur in any part of the body that comes in contact with the allergen. In severe cases, the throat can swell until it closes and obstruct your breathing -- known as anaphylaxis. How you relieve the swelling depends on the severity of your symptoms. Before you do anything, contact your healthcare provider.
Take an over-the-counter antihistamine at the first sign of swelling. Antihistamines perform one of two functions; they prevent the body from making histamine or they prevent the body from responding to it. As histamine levels drop, the swelling goes down.
Apply an over-the-counter steroid cream, such as hydrocortisone, to areas of skin affected by swelling. Steroids shrink swollen tissues and reduce your reaction to the allergen.
Shrink swollen sinuses with an over-the-counter nasal spray. Nasal sprays contain substances that help shrink sinus swelling to help you breathe.
Apply an ice pack to swollen areas, such as the face, for 20 minutes. Ice constricts the blood vessels and helps reduce swelling.