The biggest offender in many households is cigarette smoke. Outside the home, major airborne irritants include smoke, automobile exhaust, chemicals, industrial pollution, and pollen. Nature contributes plenty to the misery of an allergy sufferer. A variety of trees, weeds, and grasses produce airborne particles that prove irritating to many individuals. Pollen is generated in large amounts by a wide range of plants and plays an especially prominent role in seasonal allergy symptoms.
Antihistamines are the most commonly used drug therapy.
They offer relief of nasal allergies by blocking the effects of histamine. But histamine release is only one of many mechanisms that cause symptoms of nasal allergies. Antihistamines may relieve your runny nose, but they probably will not relieve your stuffy nose. Some antihistamines can be purchased without a prescription. Others must be prescribed by a doctor.