Testing & Diagnosis

Nearly 1 in 3 U.S. adults and more than 1 in 4 U.S. children reported having a seasonal allergy, eczema, or food allergy. Take back control of your life.

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About one quarter (25%) of adults have a seasonal allergy, 7.3% have eczema, and 6.2% have a food allergy. More than 20 million adults and 4.6 million children have asthma. These diseases are so common that it might seem like the diagnosis and treatment are straightforward and that any doctor should be able to administer the most effective therapies. However, allergists are experts in their field with specialized training that allows them to:

  • Perform allergy testing
  • Identify the source of your suffering
  • Accurately diagnose your condition
  • Treat more than just your symptoms
  • Develop a personalized plan that eliminates your symptoms
  • Provide you with the most cost-effective care that produces the best results
Seeking the help of an allergist to test for and diagnose your allergies can help you to feel much better.

When you want to pinpoint the source of your allergies or asthma…

It’s time for an allergist.

Your First Appointment

If you have never been diagnosed with allergies but think you might have them, or if you aren’t sure what causes your allergy symptoms, see an allergist. With care from a specialist, you could be feeling much better.

When you visit an allergist, the doctor will:

  • Take a medical history. You will be asked about your health, your symptoms and whether members of your family have asthma or allergies such as hay fever, hives or skin rashes like eczema.
  • Ask you about your symptoms. The doctor will want to know when symptoms occur, how often they happen and what seems to bring them on. The allergist will also ask about your work, home and eating habits to see if these can provide clues to help pinpoint your allergy.
  • Do a physical exam.
  • Conduct allergy tests. 

Taking a medical history and selecting the right tests are key to getting a good diagnosis. Allergists use their skills in these areas to help more patients feel well, stay active during the day, and rest at night. And that’s nothing to sneeze at.

One of the things that’s really nice about being an allergist is that so many of my patients come in, after we go through the diagnosis and appropriate treatment, and they thank me because what we suggested is helping them. And that’s probably the most gratifying thing of all as a physician.

Allergy Testing

Adults and children of any age can be tested for allergies. As soon as your first consultation, you can get tested. Once the results are in and the diagnosis is done, your allergist can sit down with you and tell you what you’re allergic to and, even better, what you can do about it. 

Your allergist may want to do skin testing, blood testing, or both. Any kind of allergy test is best done under the guidance of an allergist. These specialists are trained in the best methods for diagnosing and treating allergies.

Both blood and skin allergy tests can detect a patient’s sensitivity to common inhalants like pollen and dust mites or to medicines, certain foods, latex, venom, or other substances. Skin testing is the preferred method used by trained allergists, and is usually the most accurate. Blood tests may be ordered in specific situations.

It’s important to choose the right test, the one best able to aid the diagnostic process. For many reasons, that’s not an easy job. Allergy patients are often sensitized to many allergens, but are only clinically allergic to one or more specific substances. Allergists are trained to select tests that pinpoint the allergens which are actually causing the symptoms. 

These skills are important because there are many variables that can affect allergy test results. Correctly identifying a person’s specific allergic triggers helps an allergist develop the best therapies and management plans for each patient.

Board-certified allergists are specialists trained to help you take control of your allergies and asthma, so you can live the life you want. These specialists recognize that not all allergy tests are alike. They regularly review the scientific literature to learn which testing systems work better than others and how laboratory practices may affect test results.

Allergy tests should not be ordered randomly, either. They are chosen based on symptoms, environmental and occupational exposures, age, and even hobbies. All results are then interpreted in the context of the patient’s medical history.

Tests can be done for common allergens such as plant pollens, molds, dust mites, animal dander, insect stings and various foods such as peanuts, eggs, wheat, shellfish and milk. Testing also is available for some medicines, such as penicillin.

Types of Allergy Tests

Skin Testing

Allergy skin testing is the gold standard and is used along with the medical history to find out exactly what things a person is allergic to. 

Some medicines can interfere with skin testing, so you should let your allergist know about any medications you’re taking.

Skin tests are done in an allergist’s office. Skin tests give fast result and usually cost less than allergy blood tests. 

However, while testing may seem simple, it must be carried out by trained practitioners with an understanding of the variables and risks of the testing procedure. The skill of the tester can also affect the accuracy of the results.

Steps should include:

  • After reviewing the patient’s medical history and performing a physical exam, the allergist determines that allergy skin testing is both appropriate and safe to perform on you that day.
  • A trained staff member performs the skin testing under the supervision of the allergist.
  • The skin test is read and graded for the level of response.

There are two types of skin tests:

  • Prick or scratch test: In this test, a tiny drop of a possible allergen—something you are allergic to— is pricked or scratched into the skin. (This is also called a percutaneous test.) It is the most common type of skin test.
  • Intradermal test: This test shows whether someone is allergic to things such as insect stings and penicillin. A small amount of the possible allergen is injected under the skin through a thin needle.

Skin tests for allergic disorders have been used successfully for more than 100 years. Today, prick or scratch tests are the most commonly-used type of skin test. These tests are not very invasive and, for most allergens, they tend to produce quick results. If the results of prick or scratch tests are negative, they may be followed by intradermal tests, which give allergists more details about what’s causing the symptoms.

Allergy symptoms might occur during the test. The most common symptoms are itching and swelling of the skin. In rare cases, a more serious reaction can occur, so skin testing should always be done by a specialist.

Blood Testing

Blood testing involves a single needle prick, and medicine does not interfere with the results. However, it takes a long time to get the results, and depending on the test, there can be false positives. Blood tests cost more than skin tests. There are many types of allergy blood tests, and some are more helpful than others.

The risk with allergy blood tests is pain or bleeding at the needle mark. Also, a few people may faint during blood testing.

Allergy Diagnosis

Blood test and skin test results alone do not diagnose allergies. All test results, from either type of test, must be interpreted together with your medical history.

When it comes to human allergic disease, an individual’s medical history is as important as the results of an allergy test. Medical history is the critical link between allergy test results and allergic disease itself. It tells the allergist valuable information about your health overall, your experiences with possible allergens, your symptoms at various times of the year, etc. 

If the results of skin and blood allergy tests are not clear or are inconsistent with the patient’s medical history, allergists rely on their training and experience along with a patient’s medical history and a physical examination—not test results—to make the final diagnosis.

With my mom’s help, I kept a record of my allergy symptoms for 2 weeks. I wrote down when I had my symptoms, how long they lasted, where I was, what I was doing and medicines I took for them. My doctor reviewed the record but still couldn’t figure out what I was allergic to. So he referred me to an allergist for skin testing, which showed I was allergic to mold. The next step was to get rid of the mold in our home.

Skin Testing FAQs

Allergists are experts who test for, diagnose and treat allergies.

A number of different allergens will be tested. It takes about 5 to 10 minutes to place the allergens on your skin. They are usually put on the forearm in adults and on the back in children. Then you will wait about 15 minutes to see if a small red lump appears where any of the allergens were placed.

The prick or scratch test and intradermal test may hurt slightly. If you are sensitive to any of the allergens, your skin may itch where the allergen was placed.

Tell your allergist about all medicines you’re taking, including over-the-counter medicines.

Don’t take antihistamines for 3 to 7 days before the test. Ask your allergist when to stop taking them. (It’s okay to use nose [nasal] steroid sprays and asthma medicines. They will not interfere with skin tests. Talk to your allergist’s staff before the testing to find out which medications you can continue using.)

Very small amounts of allergens are tested on your skin, so skin testing is safe. During the test, the allergist will watch for a possible severe allergic reaction, but it rarely happens.

If you’re sensitive to an allergen:

With the prick or scratch test and intradermal test, a small red bump appears on the skin where that allergen was placed, and this area may itch. The larger the bump, the more sensitive you may be to it.

These results are called positive skin tests and mean that you may be allergic to the allergen tested.

Even if a skin test shows that you’re allergic to something, you may not react to it when you’re exposed to it later. Your allergist will review your medical history and skin test results to help find out what you’re allergic to.

our allergist will create a plan for controlling your allergies. This means preventing and treating symptoms. Take these steps:

Avoid or limit contact with your allergens. For example, if you’re allergic to dust mites, reduce the clutter in your house, which collects dust.

Take medicine to relieve your symptoms. Your allergist may prescribe medicines such as antihistamines, decongestants, nose (nasal) sprays, or eye drops.

Get allergy shots if the allergist says you should. Some people need them when they can’t avoid an allergen. The shots contain a tiny but increasing amount of the allergen you’re sensitive to. Whether given in shot form or under the tongue, immunotherapy involves giving gradually increasing doses of the substance to which you are allergic (also known as your allergen). The small increases over time in the amount of your allergen – things like dust, pollen, mold and pet dander – cause the immune system to become less sensitive to it. That reduces your allergy symptoms when you come across the allergen in the future. Immunotherapy also reduces the inflammation that comes with hay fever and asthma.

Most health insurance plans cover allergy testing and treatment. Ask your insurance carrier:

  • Do I need a referral from my doctor to see an allergist?
  • Does my insurance cover patient education or special services for my allergies?
  • What allergy testing and medicines does my plan cover?

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This page reviewed for accuracy June 28, 2023.