The source of your sniffles can be hard to trace. Find out if it's allergies your family may face.

Q. What is an allergy?

A. An allergy is an abnormal reaction to an ordinarily harmless substance, such as pollen or mold. It's an overreaction to something the body views as an invader.

Q. How do allergies come about?

A. When an allergen, such as a pollen grain, enters the body and comes in contact with the lining of the nose, the immune system of an allergic person initiates a chain reaction to protect itself. White blood cells, known as lymphocytes, produce antibodies that cause the release of chemicals such as histamine. Histamine, and other natural substances made by your body, cause the classic allergy symptoms—including runny nose, watery eyes, and sneezing.

Q. Whom can you see for help?

A. Allergists/immunologists are trained in the prevention, diagnosis, and treatment of immune-system problems such as allergies, asthma, inherited immunodeficiency diseases, and autoimmune diseases. Unlike a cold, allergic disease is not a condition that someone can just recover from. The help of a trained allergist can reduce how often you need to stay home from work or school due to symptoms.

To locate an allergist* in your area, visit the physician referral directory of the American Academy of Allergy Asthma & Immunology. If you are enrolled in a managed-care organization, your insurer will have a specific set of guidelines that help your primary-care physician decide when to refer you to an allergist.

Q: What are seasonal allergies?

A: Seasonal allergies, often referred to as seasonal allergic rhinitis or hay fever, affect more than 35 million people in the United States. Symptoms—such as sneezing, congestion, runny nose, and itchiness in the nose, mouth, throat, eyes, and ears—are commonly triggered in the spring and fall. Whether you experience symptoms depends on where you live and what kinds of allergens are present there.

Q: What causes seasonal allergies?

A: Warm weather and bursting blooms in the beginning of allergy season mean the release of countless airborne pollens and molds. Allergy seasons vary across the United States, but generally last from February or March through October. Microscopic pollen grains from trees, mold spores, grasses, and weeds take flight and eventually find their way into your airways.

Q: When should you see an allergist?

A: If you have been diagnosed with allergies, your physician will likely refer you to an allergist/immunologist for care because he or she is specially trained to manage and treat allergies.

A trained allergist/immunologist can provide you with more specific information about the management and treatment of allergic disease. For general information about this subject, please visit the American Academy of Allergy Asthma & Immunology.

This information is provided by the American Academy of Allergy Asthma & Immunology.

* U.S. residents only