Allergy skin testing helps find out what substances (allergens) may be causing allergy symptoms such as sneezing, runny nose, itchy eyes, or skin rashes. This test is commonly used to diagnose allergies to things like pollen, dust mites, pet dander, molds, foods, insect stings, and some medicines.

How does allergy skin testing work?

Allergy skin testing is usually done in an allergy clinic. There are two main types:

– Skin prick (or puncture) test: A small drop of a possible allergen is placed on the skin (usually the forearm or back). A tiny, gentle prick is made through the drop. If allergic, a small bump (wheal) and redness (flare) will appear within 15–20 minutes.

– Intradermal test: If the skin prick test is negative but allergy is still suspected, a small amount of allergen is injected just under the skin. This test is more sensitive but can have more false positives and is usually used for certain allergens like insect venom or medicines.

What should be expected during the test?

– The test is quick and usually not painful, but it may cause mild itching or redness where the allergen is placed.

– Both a positive control (histamine) and a negative control (saline) are used to make sure the skin reacts normally.

– Results are read after about 15–20 minutes.

How accurate is skin testing?

– Skin prick testing is highly sensitive and specific, with sensitivity around 80–85% and specificity around 77% for common inhaled allergens.

– Intradermal testing is more sensitive but less specific and is not usually the first test.

– A positive test means the body is sensitized to the allergen, but it is important to match the test result with symptoms. Not everyone with a positive test will have allergy symptoms when exposed to that allergen.

Who should get allergy skin testing?

– People with ongoing or severe allergy symptoms that are not well controlled with usual treatments.

– Those with a history suggesting allergies to foods, insect stings, or medicines.

– Children and adults of any age can be tested, but the test may be less sensitive in infants and older adults.

Who should NOT get allergy skin testing?

– People with uncontrolled or severe asthma.

– Those with certain skin conditions (like severe eczema) in the area to be tested.

– People taking medicines that can interfere with the test (such as antihistamines or some antidepressants) may need to stop these before testing—always check with the clinic first.

– Those with unstable heart disease or who are at high risk for severe allergic reactions may not be suitable for skin testing.

Are there any risks?

– Most reactions are mild, such as redness, swelling, or itching at the test site.

– Serious allergic reactions (anaphylaxis) are extremely rare, especially with skin prick testing. The test is always done in a medical setting where help is available if needed.

How to prepare for the test:

– Tell the clinic about all medicines being taken, as some may need to be stopped before the test.

– Do not apply lotions or creams to the skin on the day of the test.

– Wear clothing that allows easy access to the forearms or back.

What happens after the test?

– The results will be discussed, and a plan will be made for managing allergies, which may include avoiding certain allergens, using medications, or considering allergy shots (immunotherapy).

If there are any questions or concerns about allergy skin testing, call our clinic and we’d be happy to discuss further with you.