2013年9月21日星期六

Seasonal allergy




SEASONAL ALLERGY

Allergy is a short term inflammation of the mucous membranes that line the nasal cavity. Hay fever , a condition commonly called, is caused by pollen suspended in trees, herbs, flowers and weeds. Allergy season usually starts off spring and autumn when the trees or grass Some pollinate. When the pollen season begins and how long it lasts varies throughout the country. In the southern states, trees can begin to pollinate at the end of February and the grass may begin in late April, in the Midwestern states allergies may not push through May Another set of allergies may begin in late summer or early fall when ragweed is the cause. In Western countries there pollinated grass for a longer period and some weeds that can prevent allergies fall flowering.

Term hay fever is somewhat misleading because symptoms do not occur only in summer when the hay is traditionally collected and include fever. Hay fever is usually a reaction to pollens and grasses. The pollens that cause hay fever vary according to the season.

Spring – In general, trees (such as oak, elm, maple, alder, birch, juniper, and olive oil) .
Summer –  grasses ( such as Bermuda, timothy, sweet spring, garden, and Johnson) and weeds (such as Russian thistle and English plantain).
Fall – ragweed .

In addition, different parts of the country have very different pollen seasons. In the western U.S., mountain cedar (a juniper) is a major source of tree pollen from December to March. In the dry Southwest, pollination of grass for much longer, and fall, pollen from weeds such as Russian thistle and sagebrush can cause hay fever. People can respond to one or more pollen, so that their season of pollen allergy may be from early spring to late fall. Seasonal allergies are caused by mold spores that can be airborne for a long period in spring, summer and fall.

Allergic conjunctivitis can occur when the time substances such as pollen, direct contact with eyes.

DIAGNOSIS
Diagnosis to determine what is causing your symptoms, your doctor will begin with a clinical history. Allergy symptoms that occur during the pollen season is the biggest indication that you suffer from allergies. In other words, if April showers bring May flowers, more sneezing and a runny nose, allergies are probably the culprits. Allergies can be caused by many factors, including exposure to house dust and animal dander. Your doctor will want to know if you have pets, if someone smokes in the house, or are taking medication to help decipher the cause of their symptoms. Your doctor will also want to know how old he began to have symptoms of allergies and if someone in your family suffers from allergies.









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