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Get to the Bottom of Your Allergic Reactions!

Skin Testing for Allergies in Melbourne, FL

Learn more about skin testing for allergies from board-certified Allergist Dr. Pavana Beerelli in Melbourne, FL. If you have an upcoming skin testing appointment with us, check out our Do’s and Don’ts checklist to help you prepare.

“Melbourne Allergy and Asthma office was quick and easy to get an appointment even during the pandemic. Dr. Pavana Beerelli met with us by telehealth and was able to provide excellent insight into my child’s eczema and allergies. It was such a relief to finally have a treatment plan for my child. Dr. Beerelli was helpful and thorough in her approach. I would highly recommend her to anyone.”

– Danielle J, July 2020

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Skin allergy doctor Pavana Beerelli of Melbourne Allergy & Asthma review badges and affiliations

Skin Testing Overview

Allergies Tested

Methods for Skin Testing

Side Effects

Do’s and Don’ts

Allergies Tested for in a Skin Test

Skin testing is considered the primary diagnostic technique for many allergies including:

Allergic asthma, rhinitis, and conjunctivitis
Food allergies – With some foods, only half of all positive tests are true positives. Test results may need further confirmation with a food challenge.
Some medication allergies – Skin testing has been validated and standardized for the evaluation of some medication allergies. This is true for penicillin allergy skin testing. However, skin testing is not well-defined for other antibiotic and drug allergies.
Venom allergies to wasps, hornets, bees, yellow jackets, and fire ants

Skin testing for allergies on a patient's arm

Methods for Skin Testing

Allergy skin testing is done mainly through the prick/puncture technique or the intradermal technique. Prick/puncture is more commonly performed as initial skin testing for allergies. Patch testing is performed in patients who may have allergic contact dermatitis. A positive skin test alone is not sufficient to diagnose allergy. Positive skin test results should be supported by the patient’s medical history of allergic reaction. In addition to a skin test, your allergist may need to confirm a suspected allergy with a direct allergen challenge.

Skin Prick or Puncture

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

Skin Prick-by-Prick Testing for Food Allergy

Urticaria can be acute or chronic. Urticaria is chronic when it occurs daily for 6 weeks or longer and is recurring. Chronic hives generally have a different cause than acute hives. Often, there is no identifiable trigger for chronic urticaria.

Intradermal Skin Test

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.

Intradermal skin testing is typically performed when a prick or puncture test comes back negative but your doctor still believes you may be allergic to a particular substance. Because intradermal skin testing is highly sensitive, it is optimal for detecting venom allergies. However, intradermal skin testing is unacceptable for testing food or latex allergies due to the possibility of severe systemic reaction.

Because intradermal skin testing is more sensitive, there may be many small, positive reactions that are not clinically significant. This equates to more false-positives. Additionally, with intradermal skin testing, there is a higher risk of inducing a systemic allergic reaction, so prick or puncture testing is usually recommended prior to intradermal testing. This is especially true when testing for airborne allergens.

Skin Patch

Skin contact with an allergen or irritant such as plants, perfumes or cheap metal jewelry may cause contact dermatitis. Allergic contact dermatitis appears as an itchy, bumpy, red skin that may also be swollen at the site of contact. Symptom onset ranges from a few hours to 10 days after exposure to the irritant. Because contact dermatitis rash is an allergic reaction, it is not contagious.

Side Effects of Skin Testing

The wheal-and-flare reaction, characterized by a raised and swollen bump surrounded by redness, often begins to resolve within an hour.

Anaphylaxis is rare but can occur during skin testing. It is almost always associated with intradermal testing without prior prick or puncture testing.

Who Can Benefit from Skin Testing

Your skin allergy doctor will obtain a detailed medical history and perform a thorough physical exam on you. Your doctor may order additional skin, urine, or blood tests to establish the cause of your allergic reactions. Because skin allergies can be associated with other food allergies, nasal allergies, and asthma, specific testing for these conditions may be done as well.

Skin testing for allergies with patch testing on woman's back

References

[1] Patient education: Allergy skin testing (The Basics). UpToDate. Accessed July 2020.
[2] American College of Allergy, Asthma & Immunology: https://acaai.org
[3] Krzysztof, K, DuBuske, L. Overview of skin testing for allergic disease. UpToDate. Accessed July 2020.
[4] Brod, BA. Patch Testing. UpToDate. Accessed July 2020.

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Skin Allergy Testing in Melbourne, FL

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