Mild winter temperatures in many parts of the US -- the fourth warmest winter since record-keeping began -- have triggered an unusually early release of pollen from trees, which bodes badly for the millions of people who suffer from allergic rhinitis, commonly known as hay fever.

Allergists are predicting a longer, and more intense, allergy season than normal. Once people have been exposed to the early pollen, essentially priming the immune system to react to the allergens, there is little chance of relief even if temperatures cool down again. This priming effect can bring on even more severe symptoms for allergy patients, especially those with asthma, says Neil Kao, an allergist in Greenville, N.C.

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Medications, including eye drops, antihistamines and nasal sprays, can relieve hay fever symptoms for many people. For greatest effect, these products usually need to be used just before any exposure to pollen, says Stanley Fineman, an allergy specialist in Marietta, Ga.

But this year "we didn't catch it in time because we didn't know the pollen was going to start so early," says Fineman, who also is president of the American College of Allergy, Asthma & Immunology, which represents allergists. Weather websites often signal when local pollen counts start to rise.

More aggressive treatments, including immune-boosting allergy shots, are also available, and specialists expect more patients may pursue these remedies this year if their symptoms are worse than normal.

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Different pollens serve as triggers to different people. Allergy shots, which administer escalating doses of the offending allergens, work like a vaccine to create resistance in the patient. But these can take several months to become effective. Doctors increasingly are recommending faster treatment protocols that deliver the shots over a shorter period and can bring relief within a few weeks.

Allergists also may offer the same type of immunotherapy in the form of drops under the tongue, which patients can use at home after an initial visit. Pharmaceutical firms are developing immunotherapy tablets, to be taken orally, including one from Merck & Co. that has been shown in trials to reduce symptoms of ragweed allergy.

Other researchers are investigating new methods to give patients faster and more effective allergy relief, such as delivering the allergens through the skin or by way of the lymph nodes.

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