Allergic rhinitis is an inflammation of the nasal passages, usually associated with watery nasal discharge and itching of the nose and eyes.
Allergic rhinitis affects about 20 percent of the American population and ranks as one of the most common illnesses in the U.S. The symptoms occur in the nose and eyes and usually occur after exposure to dust, danders, or certain seasonal pollens in people that are allergic to these substances. Two-thirds of all patients have symptoms of allergic rhinitis before the age of 30, but onset can occur at any age. Allergic rhinitis has no sexual predilection, although boys up to the age of 10 are twice as likely to have symptoms as girls. There is strong genetic predisposition to allergic rhinitis. One parent with a history of allergic rhinitis has about a 30 percent chance of producing offspring with the disorder; the risk increases to 50 percent if both parents have a history of allergies. Patients can be severely restricted in their daily activities, resulting in excessive time away from school or work. Millions of dollars are spent each year on physician services and medication for treatment of this chronic illness.
Many perennial and seasonal allergens cause allergic rhinitis. Dust mites, cockroaches, molds and animal dander, are examples of year-around allergens. Tree, grass and ragweed pollens are primarily seasonal outdoor allergens. Seasonal pollens depend on wind for cross-pollination. Plants that depend on insect pollination, such as goldenrod and dandelions, do not usually cause allergic rhinitis. Mold spores grow in warm, damp environments. The highest mold spore counts occur in early spring, late summer and early fall, but mold spores can be measured indoors year-around. Animal allergens are also important indoor allergens. The major cat allergen is secreted through the sebaceous glands of the animal's skin. These small, light proteins are capable of staying suspended in the air for up to six hours and can be measured for several months after a cat is removed from an indoor environment.
Characteristic symptoms include repetitive sneezing; rhinorrhea (runny nose); post-nasal drip; nasal congestion; pruritic (itchy) eyes, ears, nose or throat; and generalized fatigue. Symptoms can also include wheezing, eye tearing, sore throat, and impaired smell. A chronic cough may be secondary to postnasal drip, but should not be mistaken for asthma. Sinus headaches and ear plugging are also common
After a medical history, your physician will perform a physical exam. Often, the nasal mucosa (lining of the nose) is pale or violaceous because of the engorged veins. Nasal polyps may be seen. Classic signs of allergic rhinitis may include swelling of the eyelids, injected sclerae (the whites of the eyes may be red), allergic shiners (darkened areas under the lower eyelids thought to result from venous pooling of blood), and extra skin folds in the lower eyelids. Skin testing may confirm the diagnosis of allergic rhinitis. Initial skin testing is performed by the prick method. Intradermal testing is performed if results of prick testing are negative.
(see also SELF-CARE) The goal of treatment is to reduce the allergy symptoms. Avoidance of the allergen or minimization of contact with it is the best treatment, but some relief may be found with the following medications. Antihistamines and Decongestants Oral decongestants alone may be helpful, including pseudoephedrine. Antihistamines are available as tablets, capsules and liquids, and may or may not be combined with decongestants. Common antihistamines include brompheniramine or chlorpheniramine, and clemastine. Non-sedating (less likely to cause drowsiness) long-acting antihistamines include loratidine and fexofenadine. Nasal sprays For rhinorrhea, a nasal spray of cromolyn sodium (Nasalcrom) or a steroid nasal spray, such as flunisolide (Nasalide), beclomethasone dipropionate (Beconase, Vancenase), triamcinolone acetonide (Nasacort), and fluticasone (Flonase), may work so well that additional antihistamines or decongestants are unnecessary. It is important to remember that improvement may not occur for one to two weeks after starting therapy with steroid nasal sprays. Short courses of oral corticosteroids may usually be indicated when severe nasal symptoms prevent the adequate delivery of topical agents. Immunotherapy (Allergy shots) Immunotherapy involves giving gradually increasing doses of the substance (or allergen) to which the person is allergic. This works by making the immune system less sensitive to that substance, probably by causing production of a particular "blocking" antibody, which reduces the symptoms of allergy when the substance is encountered in the future. Before starting treatment, the physician and patient try to identify trigger factors for allergic symptoms. Skin or sometimes blood tests are performed to confirm the specific allergens to which the person has antibodies. Immunotherapy may be indicated for patients who are:
- Unresponsive to medical therapy
- Have side effects from medications
- Have recurrent sinusitis or otitis (an ear infection)
- Are unwilling or unable to use medication
- Prefer not to use medication on a long-term basis
RAST (a kind of allergy test) testing or skin testing to identify the offending allergens is often a prerequisite to immunotherapy. Immunotherapy is initiated with weekly injections of small amounts of antigen (allergen). The amount of antigen and the length of time between injections are slowly increased. Maintenance injections are usually given once every three to four weeks. The principal side effect of immunotherapy is a local reaction at the injection site, but the risk of anaphylaxis warrants caution. Immunotherapy is not a cure for allergic rhinitis. Approximately 85 percent of all patients obtain long-lasting symptom relief from immunotherapy. After three to five seasons of adequate symptom relief, it may be possible to discontinue immunotherapy. Sixty percent of all patients continue to derive symptomatic benefit, with reduced need for medications after immunotherapy is discontinued. Environmental modification should be maintained during immunotherapy.
Avoidance measures Seasonal allergens (such as tree, grass and ragweed pollens) are difficult to avoid outdoors, but can be controlled by closing windows and running air conditioners. Excessive exposure to allergens, such as outdoor molds, can be prevented by avoiding lawn mowing and other activities likely to stir these up. Maintaining an allergen-free environment also includes covering pillows and mattresses with plastic covers, substituting synthetic materials (such as foam mattresses or acrylics) for animal products (such as wool or horsehair) and removing dust-collecting household fixtures (like carpets, drapes and bedspreads). Air purifiers and dust filters may help.