What to Expect and How to Prepare for Patch Testing

While an allergy patch test is used to test a variety of substances, most patients have similar testing experiences. Below, we’ve answered some common questions about what you can expect with an allergy patch test. These answers are based on previous patient experiences, but if you have any questions not answered below, don’t be afraid to ask your dermatologist about the process. You can also consult our main page for Allergy Patch Testing.

 

How long does an allergy patch test take?

An allergy patch test will take around 48 hours to complete. The doctor will apply the allergens, dishes or panels to keep the substances in place, and hypoallergenic tape during an appointment. These materials will stay in place for at least 48 hours, which should give the allergens enough time to develop reactions. After two days, you will return to the doctor’s office to have the panels removed and the skin inspected. However, not all allergens will create a reaction within two-day’s time, so you will need to have a follow-up appointment 2-5 days after patch removal for a second reading. The doctor will assess your skin again to ensure an accurate diagnosis.

If there are no definitive results from a round of allergy patch testing (i.e. none of the allergens caused a reaction), your doctor may recommend another round of testing with a separate set of substances. In total, though, a single allergy patch test should take around one week to complete.

 

What does an allergy patch test feel like?

If you are allergic to any of the substances applied, you will likely experience an itching or burning sensation. It is important that you refrain from scratching the patch test area. This can irritate the skin, make the itching worse, and dislodge the patch, which can negatively impact your doctor’s ability to interpret the test results. Do your best to avoid the uncomfortable sensation, but if the itching and burning becomes severe or very painful, call your doctor as soon as possible. You can see photos of different types of positive reactions from the Contact Dermatitis Institute.

 

What activities should I avoid during an allergy patch test?

During a patch test, you should take care to avoid certain activities that may impact results. Swimming, for example, is never allowed, even if your doctor uses a water and sweat-resistant material. Additionally, some exercises that result in a lot of sweating, like jogging, biking, and other cardio workouts, should be avoided when possible. However, light workouts at the gym are typically permitted if your doctor uses a sweat-resistant testing material.

Additionally, do your best to avoid heat and sunlight. Heat can cause excessive sweating, which can loosen the tape. Sunlight may impact the results of the test and should be avoided during the test, especially after the panels are removed.

 

Can I shower during an allergy patch test?

It is important to minimize and limit your exposure to water during an allergy patch test. In some cases, your dermatologist will use a water-resistant covering over the test panels. If this is the case, they will communicate to you that you can safely shower. However, this will depend on the materials your doctor uses. Ask about recommended shower frequency when the panels are initially applied.

Remember that, even after the panels are removed, you should limit showering and avoid scrubbing the test site until you have your follow-up appointment 2-5 days after the initial panel removal.

 

What happens if a patch falls off?

Your doctor will attach test panels or dishes to the skin with hypoallergenic tape. If you notice the panel or dish becoming loose, you can use hypoallergenic tape to reattach it to your skin. If this happens, take care to only apply tape to the outside edge of the panels so that you do not accidentally contaminate the skin underneath.

 

What if my results are negative?

Negative results are common with an allergy patch test. Patch testing helps you and your dermatologist narrow the list of potential allergens that are causing the allergen contact dermatitis. If you test negative on your initial patch, don’t worry – this just means you are closer to finding a specific diagnosis. The doctor will often order another round of testing done with a new set of allergens. They may also recommend a different type of allergy skin test.

No matter your allergy test results, West County Dermatology is equipped to help you navigate the procedure. An allergy patch tests requires three visits to a clinic within a short amount of time. Our location in Chesterfield, Missouri makes this experience easier for your schedule. If you suspect you have a skin allergy, contact us to schedule an appointment or virtual visit today.