Patch Testing for Skin Allergies
A patch test can help determine which allergens are causing a patient’s contact dermatitis.
Allergic contact dermatitis is caused by having once come into contact with a certain substance (an allergen) that then triggers a response by the body’s defensive systems toward that substance. When the body comes in contact with this allergen again, the response can be robust inflammation of the skin.
This rash can come on quickly after contact with the substance or can take hours.
A patch test is performed by taping possible allergens to the upper back, waiting several days, and returning to the doctor to see the results. Occasionally, another examination will be performed several days later to see if any reaction was delayed.
After patch testing has been concluded, if a specific allergen is determined, the patient will be able to avoid it and prevent further inflammation of the skin. If the allergen cannot always be avoided, moisturizers and steroid ointments may be able to help. However, patch testing does not always reveal an allergen that is relevant to the patient’s rash, and occasionally patients do not react to any of the substances tested in a patch test.
The only way to prevent further contact dermatitis is to avoid the substance that irritates the skin.
We are able to refer patients to UAB Dermatology for Patch Testing if it is required.
Download this Patch Testing Information document
*Source: Mayo Clinic