What is Hay Fever?

Simply put, it's a misnomer. Doctors and researchers who specialize in allergies prefer the term "allergic rhinitis," because hay is not the culprit and most allergies don't involve any fever.

About 40 million Americans suffer from the condition, whatever it's called. Symptoms include stuffy and runny nose, watery and itchy eyes, sneezing, wheezing and cough.

"There are dozens of substances that potentially can cause trouble in those of us who are susceptible to allergies, but trees are usually the first on the scene during spring allergy season," says Jay M. Portnoy, M.D., president of the American College of Allergy, Asthma and Immunology (ACAAI) and chief, section of allergy, asthma & immunology at Children's Mercy Hospitals & Clinics in Kansas City, Mo. "Rain can provide some initial relief by reducing tree pollen counts, but it also can spur the growth of grass and weeds later in the spring and in early summer, producing more pollen."

In many parts of the country, this spring saw a perfect storm of allergy conditions.

"A dry and cold winter followed by recent heavy rains has resulted in a slightly delayed onset of spring tree pollens," said Paul Ratner, M.D., Medical Director of Sylvana Research in San Antonio, Texas. "The primary tree pollen, Oak, began appearing mid-March, and within a week, extremely high pollen counts were recorded. The tree pollen season is expected to last through early May."

Heavy precipitation in many areas of the U.S. is associated with a greater release of seasonal pollens according to Clifford W. Bassett, M.D., a fellow of the ACAAI and a clinical assistant professor of medicine at the Long Island College Hospital in Brooklyn, N.Y.

"We are seeing many patients over the past several weeks, both adults and children, with complaints that may be difficult for them to differentiate from a cold, allergy or sinus problem. Once they are diagnosed with a seasonal allergy, an individual allergy treatment program can be prescribed for their relief," Dr. Bassett said.

"Last year we had record high pollen levels in New York City and expect that trend to continue. It's very important to begin treatment before symptoms progress," he said.

There has been a prolonged snow cover on the ground from mid-November through mid-March said ACAAI President-Elect Richard G. Gower, M.D., Marycliff Allergy Specialists in Spokane, Wash. "Melting snow has revealed an abundance of outdoor mold growth and the use of indoor humidifiers has contributed to increased indoor mold counts. Trees began pollinating in early February and will continue through June, overlapping with our grass season in May and June."

The five most common allergens, according to the ACAAI are:

1. Trees produce pollen, the dust-like, male reproductive parts of plants that cause most allergies. In some southern states, trees can produce pollen as early as January, while pollen production usually begins in April in the north. The oak tree, which is prevalent throughout the United States, produces large quantities of pollen and is a major cause of allergies. Evergreens also can be troublemakers. Cedar, juniper, cypress and sequoia trees have all been known to cause allergies – and if you're allergic to one, you may be allergic to them all. Other suspects include elm trees, which are common in the eastern and midwestern regions, birch trees, olive trees, sycamores, and poplars, including cottonwoods, balsam and aspen.

2. Grasses usually come along to stir up allergy symptoms after trees are through pollinating – typically from late spring to early summer. Common culprits are timothy grass, Bermuda grass, sweet vernal, red top and some blue grasses.

3. Weeds are guilty of causing most of the allergy misery that occurs in the late summer and early fall. Top on the list of offenders is ragweed – which affects as many as 75 percent of all hay fever sufferers. Ragweed is found in virtually every region of the United States and, with 17 different species of the weed, there's plenty of pollen to keep people sneezing and sniffling until frost. Other common weed allergens are sagebrush, found predominantly in the west, pigweed and goosefoot pollen.

4. Molds are microscopic plants that reproduce by sending tiny spores into the air. They thrive in areas that are warm, dark and moist. Unlike pollen, which appears only in the warm weather months, mold can lurk in your house year-round.

5. Dust Mites are small (hundreds can live in a single gram of dust), eight-legged creatures that belong to the same family as spiders, chiggers and ticks. These culprits are hardy creatures that live well and multiply easily in warm, humid places. Favorite hideouts include carpets, upholstered furniture, bedding, clothes, soft toys and the fur of pets. The intruder is particularly malicious when trapped inside a closed-up house.