Being allergic to something, whether it is pollen in the air, a pet cat or a type of food, means that your immune system reacts adversely to the allergen. Your body makes antibodies when you are exposed to something to which you are allergic. When people come in contact with an allergen, they suffer symptoms such as a runny noise, itchy eyes, hives or, in the case of food, sometimes vomiting or a tingling sensation in the mouth and throat.
Allergy medications, both over-the-counter and prescription strengths, are designed to block chemical reactions that occur from an allergen and to relieve symptoms. Allergy medications are available in several different forms, including oral or inhaled drugs, topical ointments, eye drops and intranasal medications that are prescribed according to the specific allergy and its symptoms.
Decongestants
Allergy medications containing decongestants are used to relieve nasal congestion and sinus pressure, symptoms that are called allergic rhinitis. Decongestants such as pseudoephedrine are taken orally either once or several times a day, depending on its strength and the severity of the allergies. Another decongestant, phenylephrine, is an active ingredient found in nasal sprays and can be used to relieve nasal allergy symptoms as well. Allergy medications to treat itchy and watery eyes include tetrahydrozoline and are available over-the-counter or by prescription. Oral decongestants are generally fine to use on a daily basis, though some exceptions apply for pregnant women and people with high blood pressure. Nasal sprays and eye drops used to relieve allergy symptoms should be used sparingly to avoid uncomfortable side effects such as rebound congestion and red eyes.
Antihistamines
During an allergic reaction, your body emits an inflammatory substance called histamine. Antihistamine medications are used to block the body's production of histamines and therefore help minimize allergy symptoms including itching, swelling, runny nose and watery eyes. Like decongestants, antihistamines can be taken by mouth, by nose or in the eyes, depending on the specific allergy complaints. Active ingredients in antihistamines used to manage allergic reactions include loratadine, fexofenadine, olopatadine and ketotifen. People who wear contact lenses may have a greater risk of eye inflammation when using antihistamine eye drops to alleviate allergy symptoms.
Corticosteroids
Corticosteroids are a powerful class of allergy medications that are usually available only with a prescription from a doctor. This type of allergy drug reduces inflammation that is present in the body in response to an allergen. Corticosteroids are used in inhalers for asthma sufferers and are active components in medicated creams that are applied to stop the itching associated with eczema, which can develop in some people who have allergies. Nasal sprays and oral medications are used when antihistamines and decongestants do not provide enough relief to an allergy sufferer. Corticosteroids can carry a series of side effects, including eye problems and osteoporosis, and are usually prescribed as a short-term solution to allergy symptoms.
