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Allergies Health Center

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Indoor Allergy Triggers

Discover what’s behind your symptoms.

Diagnosing Indoor Allergies

Dander, droppings, dust -- if every home has them, how can you narrow down what is triggering your indoor allergies? There are essentially two ways: By trial and error, and through allergy testing.

For the trial-and-error approach, searching for patterns is key, Chiu tells WebMD. Perhaps you visit your sister and her cats every Monday. Before long you notice every Monday that you’re blocked up, blowing your nose, and rubbing your eyes. It doesn’t take long for this flash of insight: You’re allergic to cats.

Of course, discovering what’s triggering your indoor allergies isn’t always that easy. Which is why “the best way to find out what you’re allergic to is to see an allergist,” says Alan Goldsobel, adjunct associate clinical professor at Stanford University Medical Center, and spokesman for the American Academy of Allergy, Asthma & Immunology.

An allergist can cut through the guessing games with examinations and tests, zeroing in on what’s behind your indoor allergy symptoms, Goldsobel tells WebMD. Allergists generally diagnose allergies in three ways:

  • Personal and medical history: Through questions about your personal and medical history, an allergist will note your symptoms and narrow down their possible causes.
  • Examination: To further determine symptoms and causes, an allergist will also perform a physical examination, paying special attention to your eyes, nose, throat, chest, ears, and skin. Test may also include X-rays of your lungs or sinuses.
  • Skin, patch, or blood tests:For many people, skin tests are the most accurate and least expensive way to confirm suspected allergens, according to the Asthma and Allergy Foundation of America. Results can take as little as 20 minutes, and generally show up as redness, swelling, and itching at the site of the scratch or needle prick.

With patch tests, the doctor places a potential allergen on your skin, covers it with a bandage, and checks your reaction 48 hours later. If you develop a rash, you’re allergic to that particular allergen.

Blood (RAST) tests are used when skin testing isn’t possible, such as when people are taking certain medication or have a skin condition. Your allergist will take a blood sample and send to the lab. The lab adds the suspected allergen to the blood sample, and measures how many antibodies your blood makes to attack the allergen.

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