In Medical Dermatology

More than 50 million Americans experience various types of allergies each year, according to the Asthma and Allergy Foundation of America. Those suffering from skin allergies – or contact dermatitis – can turn to a licensed dermatologist for help.

Skin allergies affect both children and adults but are far more common in children, especially in ages 0 to 4 years. The CDC states that 8.9 million children reported skin allergies in 2017.

Skin allergies present as an inflammatory reaction on the skin that occurs when skin comes in contact with a foreign substance. Common skin allergy symptoms include:

  • Itching
  • Burning
  • Dryness
  • Cracking
  • Scaling
  • Bumps
  • Blisters
  • Oozing
  • Swelling
  • Tenderness

Skin allergies can be difficult to prevent without knowing the cause of irritation. That’s where dermal allergy testing – also called patch testing – comes in. Patch allergy testing is a diagnostic procedure performed by a dermatologist. It is an effective way to diagnose skin allergies in both children and adults. Patch testing is a popular method of allergy diagnosis because of it non-invasive application and accuracy in identifying the exact cause of an allergic reaction.

How does patch testing work?

A dermatologist performs a patch test, starting with a skin examination. Your physician will then place a number of small patches on the skin – often 25 or more – usually on the upper back. The patches, which are secured with hypoallergenic tape, contain substances known to cause skin reactions or irritation. Common irritants include wool, rubber, plants and resins. Some additives in cosmetics, topicals and clothing fibers may be tested as well. The patches will remain on the skin for two days, during which time you must keep the area dry and avoid sweat-inducing activity. After two days, the patient returns to have the patches removed. The dermatologist will examine the patched areas and identify any inflammation or breakouts.

What do patch test results look like?

Dermal patch allergy testing in Columbia

If the patient has a reaction in one or more of the patched areas, a skilled dermatologist will be able to identify the specific substance to which the patient is allergic. The dermatologist will provide advice on how to best avoid that substance or suggest alternatives that don’t contain the allergen. If no irritation occurs on the skin after the patch test is completed, a second patch test may be administered to screen for more substances. The skin is also examined days after the original test results for any delayed reactions.

There are many variables connected to patch testing, so this diagnostic procedure should always be performed by a licensed dermatologist who can properly administer the test and accurately interpret the results.

What are the pros/cons of patch testing for skin allergies?

Patch testing does not treat or cure a skin allergy but instead should be used as a tool to provide understanding of your allergy triggers. There are many advantages to patch testing:

  • It is a simple, non-invasive test the is safe for children and adults.
  • It can provide valuable information related to specific skin allergies for a wide range of allergens.
  • It can help rule out other types of dermatological conditions once the cause of a rash is known.
  • Most insurance providers cover patch testing.

The only risk associated with patch testing is the potential for mild skin irritation at the test areas. In rare cases, the patches will cause a severe allergic reaction. If this occurs, testing will be discontinued immediately.

Patch testing provides an excellent way to learn more about body-specific allergens and what substances to avoid. Learn more about patch testing and schedule a patch test a Columbia Skin Clinic.


Physician Assistant Laura Winn