Treatment consists of environmental measures to avoid allergen exposure, drugs, and desensitization. For any disease with an inherent or hereditary component, prevention by avoidance of allergens is usually the most effective means of treatment. Avoidance is not always possible or practical, however, and so medications are needed to control symptoms. In some cases, the immune response itself can be altered by desensitization therapy.
Environmental measures
Avoidance of an allergen is recommended on the basis of a clinical history of symptomatic allergy and not because of a positive skin test alone. Appropriate measures in individual cases may include:
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the removal of household pets |
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control of house dust exposure by frequent cleaning and avoidance of dust-collecting toys or other objects in patient's bedroom |
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use of air-cleaning devices with high-efficiency particle filters |
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dehumidification and repair of leaking pipes to prevent mold growth, and |
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avoidance of pollen and outdoor molds. |
Avoidance of pollen or molds is impossible unless the patient is able to stay in an air-conditioned home or office. Contact may be diminished by:
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wearing sunglasses |
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driving with the car windows shut |
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avoiding walks in the countryside (particularly in the late afternoon when the number of pollen grains is highest at ground level), and |
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keeping the bedroom window shut at night. |
These measures are rarely sufficient in themselves to control symptoms and additional drug therapy may be required. Exposure to pollen is generally lower at the seaside, where sea breezes keep pollen grains inland. In some cases, the patient might arrange a holiday trip to a pollen-free area during the peak pollen season.
In the cases of occupational allergy, every effort should be made to modify the patient's work routine and to employ industrial hygiene measures to avoid allergen exposure; however, if these measures fail, a change in the patient's job may be necessary.
Drug Treatment
1) Antihistamines
Antihistamines remain the most common therapy for rhinitis. They are particularly effective against sneezing, but are less effective against nasal discharge and have little influence on nasal blockage. The earlier antihistamines (eg, chlorpheniramine and promethazine) cause sedation. More recent drugs such as astemizole, cetirizine, loratidine, and terfenadine specifically target histamine receptors; they do not cross the blood-brain barrier and therefore do not cause drowsiness. The drugs in this group are more or less equally effective, but choice may be dictated by various cautions and interactions with medications being taken for other conditions. Advice over this should be sought.
2) Decongestants
Decongestant drugs are widely used for the treatment of nasal obstruction. They may be taken orally, or more commonly applied directly as nasal drops or sprays. If used for prolonged periods, rebound congestion can occur as tissues become resistant to the effects of the medication. This can often result in worse congestion than before. Local decongestants may be the only effective treatment for vasomotor rhinitis , but they should be used carefully to avoid rebound nasal obstruction. Usually, such preparations are prescribed for only a limited period to open the nasal airways for administration of other therapy, particularly topical corticosteroids.
3) Anti-inflammatory drugs
Two types of anti-inflammatory drug are used in the treatment of allergic rhinitis:
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Sodium cromoglycate and nedocromil sodium. These drugs are thought to act by blocking inflammatory mediators. They are applied topically in spray or powder form and are used in the prevention and treatment of mild to moderate allergic rhinitis. They are safe for use in children and are very effective in the management of allergic conjunctivitis. |
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Corticosteroids. The most effective treatment for rhinitis is the use of small doses of topically administered corticosteroid preparations (eg, beclomethasone or fluticasone spray). The amount used is insufficient to cause systemic effects and the effect is primarily anti-inflammatory. Use of these preparations should be started prior to the beginning of seasonal symptoms. The combination of a topical corticosteroid with a non-sedative antihistamine taken regularly is particularly effective in preventing symptoms. Use of nasal corticosteroid sprays is generally safe, though minor burning and nosebleed can occur. Prolonged use should always be subject to periodic monitoring. Corticosteroid eye drops should be used very sparingly for brief periods only to control acute severe allergic conjunctivitis, with careful monitoring by an ophthalmologist. |
4) Desensitization
Allergen injection therapy has been shown in many clinical trials to be effective in treating allergic rhinitis. However, because of the length of treatment required and the potential danger of serious reactions, injection treatment is only used in patients whose symptoms are uncontrolled despite appropriate environmental measures and symptomatic medication.
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