Allergic rhinitis, or hay fever, is a reaction that occurs in the eyes, nose, and throat when airborne irritants (allergens) trigger the body's release of histamine. Histamine causes tissue swelling and fluid production in the fragile linings of nasal passages, sinuses, and eyelids. There are two types of allergic rhinitis: Seasonal: Occurs particularly during pollen seasons Perennial: Occurs throughout the year The most common causes of allergic rhinitis include pollen (from trees, grass, or weeds), dust mites, mold, cockroach droppings, and animal dander. In addition to sneezes and sniffles, people with perennial allergic rhinitis may experience recurrent ear infections or fatigue. They may snore or breathe through the mouth. Children and adolescents may perform poorly in school. Allergic rhinitis is diagnosed by your doctor based on a thorough medical history and physical exam. In addition to the symptoms listed here, the doctor may find dark circles or creases under the eyes and swollen tissue inside the nose. The best way to treat allergies is to avoid allergens. This may involve using air conditioning during pollen season; avoiding areas where there is heavy dust, mites, or molds; or avoiding pets. Treatment for allergies also may include the following: Antihistamines:These help to decrease the release of histamine, possibly calming symptoms of itching, sneezing, or runny nose. Some examples of antihistamines are diphenhydramine (Benadryl) or hydroxyzine (Atarax). These medications may cause drowsiness. Nonsedating antihistamines:These highly-selective antihistamines work just as well as the older medicines but without the side effect of drowsiness. Nonsedating antihistamines include cetirizine (Zyrtec) or loratadine (Claritin). Anti-inflammatory nasal sprays:These long-acting sprays help to decrease swelling in the nose and other allergy symptoms. Steroid nasal sprays:These sprays also help to decrease swelling in the nose. Steroid nasal sprays work best when used before symptoms start, but they also can be used during a flare-up. Decongestants:These help by making the blood vessels in the nose smaller, decreasing congestion. Decongestants can be purchased over the counter or by prescription. Allergy shots: Allergy shots are a treatment option for severe allergies. Your doctor may prescribe them when other treatments do not control your allergy symptoms. Allergy shots can treat multiple allergies, allergic asthma, or allergies to insect stings. They work by slowly exposing you to small but increasing amounts of allergens. Over time, your body develops a tolerance to them. The procedure involves injections several times a week for about seven months. Then you will have monthly shots for up to five years. It's important to note that allergic rhinitis is a common problem associated with asthma. For some people, controlling asthma means controlling allergic rhinitis, according to allergy and asthma experts. Guidelines from the World Health Organization recognize the connection between allergic rhinitis and asthma. Although the link isn't fully understood, one theory asserts that rhinitis makes it difficult to breathe through the nose, which hampers the nose's normal function. Breathing through the mouth doesn't warm the air or filter or humidify it before it enters the lungs, which can make asthma worse.