An allergy is on the unusually strong reaction to a substance. Many things can cause allergies. The most common cause is pollen. Trees usually produce pollen in the spring, grasses in the summer and weeds in the fall as part of their reproductive process.

Other causes include organisms such as dust mites and molds. Chemicals, plants and dead skin particles from dogs and cats can also cause allergic reactions. So can insectstings and some foods. The most common kind of allergic reaction is itchy, watery eyes and a blocked or watery nose. Allergies can also cause red, itchy skin. Some reactions can be life-threatening—for example, when breathing passages become blocked.

Avoiding whatever causes an allergy may not always be easy. Antihistamine drugs may offer an effective treatment. Another treatment used in some cases is called immunotherapy. A patient is injected with small amounts of the allergy-causing substance. The idea is that larger and larger amounts are given over time until the patient develops a resistance to the allergen.

posted on 2007-07-15 10:05 BL 阅读(198) 评论(0)  编辑  收藏 网摘收藏