What Are the Benefits of Allergy Testing?
Allergy tests, combined with the knowledge of your allergy specialist to interpret them, can give precise information about what you are as well as what you are not allergic to. Allergy testing should always occur along with a physical examination and a discussion about your past and current symptoms.For instance, if you wheeze when you are at home and don't know why, you don't have to get rid of your cat if your allergy testing shows you are allergic to dust mites but not cats. With this information, you and your allergist can develop a treatment plan to manage or even get rid of your symptoms.
Should I Be Tested?
Testing done by an allergist is generally safe and effective for adults and children of all ages. Symptoms which usually prompt the allergist to perform skin testing include:
- Respiratory: itchy eyes, nose or throat; nasal congestion, runny nose, watery eyes, chest congestion, cough or wheezing
- Skin: hives, itchiness or atopic dermatitis
- Abdominal: cramping and diarrhea or constipation consistently after eating certain foods
- Severe reactions to stinging insect stings (other than swelling at the site of the sting)
- Anaphylaxis (an-a-fi-LAK-sis): a serious allergic reaction that affects many parts of the body at the same timeMost symptoms are caused by one or more of these allergens:
- Dust mites (tiny bugs you can't see) that live in your home
- Proteins from furry pets, which are found in their dander, saliva and urine (it's actually not their hair)
- Molds in your home or in the air outside
- Tree, grass and weed pollen
- Cockroach body parts and droppingsMore serious allergic reactions can be caused by:
- Venom from the stings of bees, wasps, yellow jackets, fire ants and other stinging insects
- Certain foods
- Natural rubber latex
- Certain medications and drugs
Types of Allergy Tests
Different allergens bother different people, so your allergist will determine which test is the best for you.The allergen extracts or vaccines used in allergy tests performed by allergists meet U.S. Food and Drug Administration (FDA) requirements, making them safe for use.
Skin Allergy Testing
This type of testing is the most common and is relatively painless. A very small amount of certain allergens is put into your skin by making a small indentation or "prick" on the surface of your skin.
If you have allergies, just a little swelling will occur where the allergen(s) which you are allergic to was introduced. For example, if you are allergic to ragweed pollen but not to cats, only the ragweed allergen will cause a little swelling or itching. The spot where the cat allergen was applied will remain normal.
You don't have to wait long to find out what is triggering your allergies. Reactions occur within about 15-20 minutes. Reactions typically then go away within 30 minutes. If your prick skin tests are negative but your physician still suspects you might have allergies, more sensitive intradermal tests will be used in which a small amount of the allergen is injected just under the skin, similar to a tuberculosis test.Skin allergy testing has to be done in an allergist's office to minimize the risk of rare side effects.
After allergy testing is completed, allergy shots (immunotherapy) may be recommended.Allergy shots can reduce your reaction to allergens, which can result in fewer or less severe symptoms. They may also prevent children who have allergic rhinitis from getting asthma.2 Recommendations on when to get allergy shots vary, but in general you and your doctor may consider them when:
- Allergy symptoms are severe enough that the benefit from the shots outweighs the expense and the time spent getting the shots.
- You are allergic to only a few substances, and they are hard to avoid.
- Avoiding allergens and using medicine do not control symptoms, or you have to take medicine all the time to control symptoms.
- Side effects of medicines are a problem.
- You want a treatment for the cause of your allergy, rather than treatment for just the symptoms.
- You have another condition that is being affected by allergic rhinitis, such as asthma.
- You want to lower the chance that you will develop asthma.
When you get allergy shots (immunotherapy), you receive small doses of substances that you are allergic to (allergens) under your skin. This helps your body "get used to" the allergen, which can result in fewer or less severe allergy symptoms.
Blood Allergy Testing
This test involves drawing blood, so results are not available as rapidly as with skin tests. Blood tests are generally used when skin tests might be unsafe or won't work, such as if you are taking certain medications, or have a skin condition that may interfere with skin testing.
Lung function testing
Spirometry: This pulmonary function test for asthma is a simple breathing test that measures how much air you can blow out of your lungs and how quickly. It is often used to determine the amount of airway obstruction you have. Spirometry can be done before and after you inhale a short-acting medication called a bronchodilator, such as albuterol. The bronchodilator causes your airways to expand, allowing for air to pass through freely. This test might also be done at future doctor visits to check your progress and to help your doctor determine if and how to adjust your treatment plan.
Patch Skin Allergy Testing
Another method is to apply an allergen to a patch, which is then placed on the skin. This may be done to pinpoint a trigger of allergic contact dermatitis. If there are allergic antibodies in your system, your skin will become irritated and may itch, much like a mosquito bite. This reaction means you are allergic to that substance.
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