Text B. Types of Allergic Reactions.

 

The different types of allergic reactions are generallycategorized by what causes them, the part of the body most affected, and other features.

Allergic rhinitis is a common type of allergic reaction. It is an allergy to airborne particles - usually pollens and grasses but sometimes molds, dusts, and animal danders - that causes sneezing; an itchy, runny, or stuffy nose; itching; and irritated eyes. Allergic rhinitis may be sea­sonal or perennial (year-round).

Part I. Seasonal Allergic Rhinitis.

Seasonal allergic rhinitis is an allergy to airborne pollens, commonly referred to as hay fever or pollinosis.

Pollen seasons vary considerably in different parts of the country. In the eastern, southern, and midwestern United States, the pollens that cause hay fever in the spring usually come from trees such as oak, elm, maple, alder, birch, juniper, and olive; in the early summer, from grasses such as bluegrasses, timothy, redtop, and orchard grass; and in the late summer, from ragweed. In the west­ern United States, the grasses pollinate for much longer, and there are other fall weeds. Occasion­ally, seasonal allergy is caused by mold spores.

 

Some prescription and nonprescription antihistamines

Prescription	Nonprescription
Astemizole	Brompheniramine
Azatadine	Chlorpheniramine
Cetirizine	Clemastine
Cyproheptadine	Dexbromphehiramine
Dexchlorpheniramine	Diphenhydramine
Loratadine	Phehindamine
Methdilazine	Pyrilamine
Promethazine	Triprolidine
Terfenadine
Trimeprazine
Tripelennamine

Symptoms and diagnosis

Once the pollen season starts, the nose, roof of the mouth, back of the throat, and eyes itch grad­ually or abruptly. Watery eyes, sneezing, and a clear watery discharge from the nose usually fol­low. Some people develop headaches, coughing, and wheezing; become irritable and depressed; lose their appetite; and have trouble sleeping. The inner eyelids and whites of the eyes may become inflamed (conjunctivitis). The lining of the nose may become swollen and bluish-red, leading to a runny nose and stuffiness.

Seasonal allergic rhinitis is usually easy to rec­ognize. Skin tests and the person's history of symptoms can help the doctor determine which pollen is causing the problem.

Treatment

Antihistamines are the usual initial treatment for seasonal allergic rhinitis. Sometimes a decongestant such as pseudoephedrine or phenylpropanolamine is taken orally along with the antihistamine to help relieve the stuffy, runny nose. However, people with high blood pressure should avoid decongestants unless their use is recommended and monitored by a doctor.

Cromolyn sodium, a nasal spray, is another drug that may be useful. Cromolyn requires a prescription and is more expensive than common antihistamines; its effects are generally limited to the areas where it’s applied, such as the nose and the back of the throat. When antihistamines and cromolyn can’t control uncomfortable allergy symptoms, corticosteroid sprays may be prescribed by a doctor. Corticosteroid sprays are remarkably effective, and the newer ones have essentially no adverse effects. When these measures fail, oral corticosteroids may be necessary for a short time (usually less than 10 days) to bring a difficult situation under control.

People who have severe adverse affects from taking drugs, who often have to take oral corticosteroids, or who develop asthma should consider allergen immunotherapy, a series of injections that may help prevent symptoms of allergy. Allergen immunotherapy for seasonal allergic rhinitis should begin some months before the pollen season.