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Allergy Patch Testing

by Lora Stewart, MD


Patch testing is another type of allergy testing that you may not have heard about, but it can be very helpful and effective. Its technical name is Delayed Type Hypersensitivity Testing, and it has been around for more than 100 years! The first patch testing studies were used to determine the poisonous parts of certain insects.

Today we use patch testing to determine allergies that do not show up with scratch/prick testing or blood allergy testing. Patch testing can test for an allergy to metals (such as nickel), preservatives, fragrances, additives, dyes and even natural products, such as lavender or tea tree oil. Patch testing can also be used for certain types of food allergies. Patch testing is often used in patients with a rash that will not go away, in patients who have trouble when metal touches their skin, or in patients with stomach issues that might be caused by allergies.

Patch testing is quite different from scratch/prick skin testing. During patch testing, the different substances are placed on your skin (usually your back) and held in place with large stickers designed for this purpose. The stickers and allergens are left on your skin for two days and then removed. At that time, early reactions may be seen, but the final interpretation of the test will occur in one to two more days. At the final visit, positive results will be reviewed, and you and your allergist will determine if the results are relevant to your unique situation and symptoms.

Contact us at 303-706-9923 if you have any questions.