Get to the Bottom of Your Allergic Reactions!

Allergy Skin Tests Available in New Orleans

Learn more about skin testing for allergies from board-certified Allergist Dr. Reena Mehta in New Orleans, LA. Learn what to expect when you get a skin prick test, intradermal skin test, or the skin patch test. Schedule an allergy skin test today!

“Dr Mehta is a very knowledgeable and caring allergist. She was able to immediately diagnose and treat my toddler’s severe allergic reaction. She has excellent bed side manners. Her office is pleasant, staff is courteous and nice. Parking is convenient. I am very comfortable about leaving my son’s health in her hands.“

– Gauravi Naik, 2019

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Skin Test For Allergies

Overview

Methods for Skin Testing

Side Effects

Many environmental, drug, and food allergies are caused by Immunoglobulin E (IgE) reactions. A skin test for allergies can help diagnose IgE-mediated allergies, making it the primary diagnostic technique for many types of allergies including:

Drug Allergies
Venom Allergies
Food Allergies
Allergic Asthma
Allergic Rhinitis
Allergic Conjunctivitis

Can I Benefit From Allergy Skin Testing?

While skin testing can help diagnose many different types of allergies, some patients are not good candidates for allergy skin testing because they are at higher risk of experiencing life-threatening side effects such as anaphylaxis. Individuals with uncontrolled asthma, reduced lung function, and history of severe reaction to very small amounts of allergen may be offered alternative testing methods to avoid complications.

Other patients, such as those with acute or chronic urticaria (hives), are more prone to false-positive skin test results. For this reason, a positive allergy skin test is usually not sufficient on its own to diagnose an allergy. Positive allergy skin test results should be supported by the patient’s medical history of allergic reaction, and may need confirmation with a direct allergen challenge.

Allergy Skin Testing Methods

Allergy skin testing is done primarily through the prick/puncture technique or the intradermal technique. Prick/puncture is more commonly performed as an initial skin test for allergies to ensure that intradermal testing is safe. Patch testing for allergies is a third method of skin testing that’s used more sparingly to test for contact dermatitis.

Skin Prick Testing For Allergies

Skin prick testing for allergies, also called the puncture technique, involves applying liquid droplets of a concentrated allergen extract to the surface of the forearm or upper back. Both positive controls known to elicit a reaction and negative controls are applied. Your allergist will then make 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, called a 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.

Skin prick testing for allergies is sensitive, but not very specific. It accurately predicts positive results less than 50 percent of the time. However, a negative allergy skin test is 95 percent accurate in confirming the absence of an IgE-mediated allergy. Therefore, a false-negative skin allergy test result is very uncommon.

Allergist performing skin testing for allergies

Extract or Raw Fruit

Some food allergies are evaluated using fresh food allergen rather than a commercially-prepared extract. Fruit allergies are often tested in this way. Your allergist will use a device to prick the raw fruit and then your skin.

Intradermal Skin Test

Intradermal skin 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.

The intradermal method involves injecting a small amount of allergen extract directly under the surface of the skin through a needle. Just like a skin prick test, 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.

Because intradermal skin testing is more sensitive than the puncture method, there may be many small positive reactions to intradermal testing that are not clinically significant. Your allergist will be able to discern false positives, or advise additional testing when appropriate.

The high sensitivity of intradermal skin testing is ideal for detecting venom allergies, however intradermal skin testing is not recommended when testing for food or latex allergies due to risk of inducing a severe systemic allergic reaction. With intradermal skin testing, there is a higher risk of inducing a systemic allergic reaction in general, so prick or puncture testing is usually recommended prior to intradermal testing. This is especially true when testing for airborne allergens.

Skin Patch Test For Allergies

A skin patch test for allergies helps identify specific allergens in allergic contact dermatitis (ACD). It can also be used to make the diagnosis of ACD. During a closed skin patch test, a patch containing the suspected allergen is applied to the skin on the upper back. The patch remains mounted on the skin for about 48 hours. Then, it is removed at various times over the course of a week by your allergist, who will check for any signs of irritation or allergic reaction. Skin patch testing helps to identify delayed but positive allergic reactions to allergens such as nickel metal, neomycin antibiotics, and corticosteroids.

Allergy Skin Testing Side Effects

The wheal-and-flare reaction, characterized by a raised and swollen bump surrounded by redness, is a common side effect of skin testing. This effect is temporary and often begins to resolve within an hour.

Anaphylaxis can also occur during skin testing, but this is especially rare when proper skin testing protocol is followed. Anaphylaxis secondary to skin testing is almost always associated with intradermal testing without precautionary prick or puncture testing.

Skin allergy rash side effect caused by skin testing

Skin Testing for Allergies in New Orleans

Dealing with an unknown allergic reaction? Get tested in New Orleans by a skin allergy specialist. Dr. Mehta has a reputation for developing strong relationships with her patients and being exceptionally attentive to their needs and concerns.