As winter gives way to spring, most Canadians look forward to shedding their heavy winter clothes and getting reacquainted with the great outdoors. Unless they’re hay fever sufferers, that is.

Hay fever, or seasonal allergic rhinitis, afflicts an estimated 20% to 25% of Canadians, says Dr. Alan Kaplan, a physician in Richmond Hill, Ont., and chairman of the Family Physician Airways Group of Canada, which helps family physicians assist patients with asthma and chronic obstructive pulmonary disease, or COPD.

The stuffy, runny nose, sneezing and watery eyes that usually accompany hay fever are a lot like symptoms of a cold. The cause, however, is completely different. Unlike colds, which are caused by viruses, says Kaplan, hay fever results from a reaction to substances called allergens, which include pollen and spores. Sources include tree and grass pollen, ragweed and fungus resulting from mould that grows on dead leaves.

“When a hay fever sufferer inhales an allergen, it is met by the ‘allergic’ antibody IgE,” Kaplan says. “The antigen/IgE complex binds to circulating ‘mast’ cells, releasing histamine and other chemical mediators that inflame the tissues of the nose, eyes and lungs, causing symptoms of congestion, itch and wheeze.”

The timing and duration of hay fever season depends on the cause of the allergies and where the sufferer lives. In Ontario and Quebec, late summer and fall tend to be worst because of ragweed. Manitoba has problems with tree and grass pollens in the spring and early summer. And in British Columbia, tree and grass pollen appear much earlier — often in February. The tree-pollen season usually lasts two to three weeks, while grasses and weeds last at least a month. Moulds and spores, which appear in the fall (or spring, stirred up when raking last year’s fallen leaves), usually stay at high levels for about two weeks.

Because all pollens are fairly large, they mainly affect the nose rather than the lungs, says Dr. Richard Warrington, Winnipeg-based president of the Canadian Society of Allergy & Clinical Immunology. “Because of their size, they can’t penetrate the deeper area of lungs,” he says. “However, when it rains, pollen granules often burst open, releasing smaller particles that are easily inhaled.”

Hay fever symptoms can range from mild to severe. And although allergic reactions tend to come and go, they can lead to other problems, such as a susceptibility to sinus infections, as well as such conditions as asthma, eczema and dermatitis.

Fortunately, seasonal allergies may improve as you age because our immune systems become less reactive over time.

When it comes to treatment, prevention is the best medicine, says Kaplan: “The first step is to try to control your environment and avoid the allergens that cause you grief.”

That means staying indoors when pollen counts are high — particularly in the early morning and late afternoon. Keep your windows closed to shut out tree pollen and grasses, and use the air conditioner. Clean your air conditioner’s and furnace’s filters and ducts regularly and use a vacuum cleaner with a HEPA filter, so allergens are not recycled.

Antihistamines, which block the release of histamines, come in both oral and nasal forms and are available as prescription drugs and as over-the-counter remedies. The latter tend to be shorter-lasting and are used to relieve mild to moderate symptoms. While most antihistamines no longer make you drowsy, they may leave your mouth, skin and eyes feeling dry.

Nasal sprays and eye drops — many of which are available only by prescription — may help to reduce inflammation of the nose and relieve sneezing, itching and your runny nose.

Immunotherapy, or allergy shots, involves regular injections of small doses of an allergen over a long period. As the body’s immune system gets used to the allergen, it should no longer react to it. However, says Warrington, if you discontinue the shots, they may not work when you resume them.

People who prefer to avoid drugs can turn to complementary and alternative therapies to treat hay fever. “Research trials into the use of homeopathic remedies have shown significant improvement in patients with hay fever symptoms,” says Sara Fitzharris, a homeopathic doctor in Kelowna, B.C.

Remedies for seasonal allergies include Euphrasia, which is used to treat inflamed, watering eyes and runny nose; and Nux Vom, which is used to treat sneezing fits and irritation to the nose, eyes and face. IE