5 Things To Know Before Your First Skin Allergy Test

Photographed By Megan Madden.
Maybe it's the phrase "skin prick" or the pictures of huge, angry red welts covering people's backs. Whatever it is, something gets us really worked up about skin allergy tests. But experts want us to know: It's time to take down our skin test anxiety a few notches.
"Most people are way more worried about this than they need to be — it's just not that big a deal," says J. Allen Meadows, MD, chair of the advocacy council of the American College of Allergy, Asthma, and Immunology. In reality, the testing itself takes up a fraction of your appointment time and, in most cases, you don't need to worry about a scary allergic reaction.
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Before you even get to the test, Dr. Meadows says your allergist will go through an extensive consultation to figure out the best plan of attack (allergy tests aren't one-size-fits-all). That initial chat will probably cover what you think you might be allergic to, how likely it is for you to come into contact with those allergens, where on your body the testing should take place, and whether or not you're already on an allergy treatment plan.
If you're really nervous about the test, your allergist can also use this time to show you what it looks like. "I demonstrate it on my arm," Dr. Meadows says. "And when people see what it actually looks like, it's a relief. They're pleased to see there's no needle involved."
So what does happen? Essentially, your allergist will decide on a bunch of allergens (up to 40) to test out. Then you'll be turned over to a technician who will actually administer the test. That person will put marks on your skin (usually your forearm or back) to keep track of what's being tested. Then she'll use a plastic scratcher to apply just a little bit of each allergen to that area. It may feel weird, but it won't be painful — it's more like scratching an itch than getting a shot.
After letting the allergens sit on your skin for about 15 minutes so your body has time to react, your allergist will interpret your results and help you figure out what needs to happen next.
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If you're getting tested for a potential drug or insect allergy or your initial skin test was unclear, that might include further testing that actually goes under your skin (in other words: an injection), explains Dr. Meadows. Those who have skin conditions or take medications that interfere with skin testing may instead get a blood allergy test, meaning you'll have your blood drawn and it'll be tested in a lab. But for most patients, skin prick testing is all it takes to figure out the next course of action.
Ahead, learn more from Dr. Meadows about how to prepare for your test and what you can really expect to happen.
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You have to lay off the allergy meds for a bit.

For up to 10 days before your test, Dr. Meadows says you'll have to stop taking your usual allergy medications. That includes both prescription and over-the-counter options. Depending on how bad your allergy symptoms are, this may be the toughest part of the test. But it's also necessary to make sure your test is accurate. After all, those medications are designed to prevent allergic reactions. So, if you took your Zyrtec the morning of your test, it's likely you wouldn't have much of a reaction to something you're allergic to. If you're worried about being able to make it through those medication-free days, talk to your allergist about other testing options.
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You're not actually getting poked.

Yes, it's called a skin "prick" test and, yes, there is a little poking device involved. But what actually happens is much closer to scratching — this isn't anything like getting your tetanus shot. According to Dr. Meadows, the vast majority of allergists don't even use metal scratchers anymore. These days, the test is almost always done with plastic scratchers, partly because patients perceive them as less painful and scary.
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Tattoos may complicate things.

Your test results are interpreted by looking at your skin's reaction, so some tattoos and skin conditions can make that impossible. If you have those, you should definitely mention it during your consultation with your allergist. Depending on the size of your tat, you may end up getting the test in a less conventional area or shape, Dr. Meadows says. Or you might end up getting fewer amounts of allergens tested at once and have multiple sessions.

"There are people who have tattoos from head to toe and they might be [more] appropriate for a blood test," Dr. Meadows says. "But we’re usually able to come up with a compromise even for people with very large tattoos — my staff is very creative."
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You will have a reaction — but it goes away.

The whole point of the test is to see if you have a reaction to certain allergens in controlled conditions. So, if you are actually allergic to those allergens, you're going to have an unpleasant reaction. The good news is that in the vast majority of cases, it's a relatively mild reaction, which Dr. Meadows describes as a mosquito bite.

But there are definitely patients who react more strongly, or react to many of the allergens being tested. That's why pretty much everyone gets a nice dose of cortisone cream right after the test to calm things down. Dr. Meadows says his staff offers patients an antihistamine and, in the unlikely event your reaction is very severe, you can get an injected dose of antihistamine.

That should be enough to make it bearable, and Dr. Meadows says there's usually no need to do anything after your appointment. Definitely feel free to apply more cortisone cream and go back to taking your usual allergy medications, though.
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There's an art to the interpretation.

About 15 minutes after your skin is scratched, your allergist will take a look at your reaction. But it's not quite as simple as a yes/no interpretation. Your allergist is looking for both the raised bumps (a.k.a. "wheals") and the surrounding inflamed red areas of skin ("flares"). Those are measured in millimeters and compared to control reactions (saline and straight histamine), which are applied to your skin along with the allergens.

But everyone's a little different, and reading results isn't always straightforward. "That’s where a lot of the art comes into interpreting these," Dr. Meadows says.

In some cases, you may end up having a reaction to something you're not actually allergic to. Or, in even rarer cases, you might not have a reaction to something you are allergic to. In general, though, skin prick tests are an accurate and helpful part of learning about your allergies — and how to treat them.
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