Dr. Trahan and his Allergy team offers comprehensive and painless allergy testing.

We provide testing for:

• seasonal allergies (including allergies to pollen, grass and trees)
• chemical allergies
• food allergies including peanut, dairy, egg and shellfish allergies
• penicillin allergies
• environmental allergies
• mold allergies
• animal and pet allergies
• skin allergies
• insect allergies and bites
• venom allergies

The goal is for you to have an excellent quality of life while being as allergy symptom-free as possible.

Blood Test for Allergies

Blood tests are helpful for identifying allergies to foods, medicines, insect stings, mold, pollen, pet dander, and dust mites.

Blood tests measure the immunoglobulin E (IgE) antibody levels in the blood, which are elevated after an allergic reaction. Generally speaking, there are 2 types of blood tests: total IgE and specific IgE.

Total IgE blood testing indicates if an allergic reaction occurred but will not be able to distinguish the specific allergen. A specific IgE test, on the other hand, measures IgE antibody levels in response to individual allergens.

Blood tests are used when skin testing may cause problems. For example, blood tests are conducted when:

• The patient’s skin is easily irritated as a result of a severe skin condition such as psoriasis or eczema.
• A skin test is too risky to conduct due to medication that interferes with skin testing, and the patient’s medicine cannot be stopped temporarily.
• Testing with a strong allergen may cause an overwhelmingly positive reaction that results in anaphylaxis.
• A skin test must be verified due to a suspected false positive or false negative. For instance, patients who may have a food allergy to crustacean seafood (shrimp, crab, lobster, etc.) may get a false positive skin test. This is due to sensitization to dust mites, spiders, and cockroaches, which are closely related to crustaceans.

Unlike skin tests, blood tests only require a single needle prick. Patients who are on medication can continue to stay on their medicine without it interfering with allergy testing. However, blood results take some time to receive and depending on the test, there may still be false positives. Additionally, blood tests typically cost more than skin tests.

Skin Test for Allergies

Skin testing is considered the primary diagnostic technique for many allergies including allergic asthma, rhinitis, conjunctivitis, food allergies, insect venom allergies, and some drug allergies. Skin tests provide fast results and are less expensive than allergy blood tests.

Skin Prick Allergy Test

Skin prick allergy testing, also called puncture testing, is commonly performed as initial testing. This method involves applying liquid droplets of a concentrated allergen extract to the surface of the forearm or upper back and making a tiny prick through each drop on the surface of your skin. If you are allergic to any of the substances, a raised and red bump (wheal) will appear within 15 to 20 minutes of the skin prick. The diameter of the wheal is compared to the controls to determine if there was a true allergic reaction.

Intradermal Allergy Test

Intradermal allergy testing is typically performed when a prick or puncture test comes back negative but your allergist still believes you may be allergic to a particular substance. This method of allergy testing involves injecting a small amount of allergen extract directly under the surface of the skin through a needle. A negative control without any allergen extract is also injected for comparison purposes. The diameters of any resulting red bumps, known as wheals, are measured to determine if there was a positive allergic reaction. Intradermal tests can help detect weaker allergic responses but can potentially trigger a severe, systemic allergic reaction. For example, intradermal testing is highly sensitive for detecting insect allergies. However, intradermal allergy tests are not advised to test for food or latex allergies due to the possibility of severe systemic reaction.