Seasonal sneezing, nasal congestion, and tearing and itching of the eyes caused by allergy to the pollen of certain plants. These plants are chiefly those pollinated by the wind (e.g., ragweed in North America, timothy grass in Britain). Antihistamines and corticosteroids may provide temporary relief, but the most effective long-range treatment is desensitization. Unless properly treated, about one-third of patients with hay fever develop asthma.

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