A skin prick test does not put a needle into your arm. A small plastic applicator presses a drop of allergen against the surface of the skin, roughly as hard as a fingernail, and then you sit for about fifteen minutes while your skin answers. The testing is the short part of a first appointment. The conversation on either side of it takes longer.
Most of the visit is talking, not testing
Before anything touches your skin, one of our allergists goes through your history with you. They will want to know when the symptoms started, which months are worst, which room and time of day they show up in, what you were doing at the time, and whether anyone in your family has asthma, hay fever or eczema.
That part is not a formality. Your history is what decides which allergens are worth putting on the panel, and a panel chosen without one is a longer test with a blurrier answer.
“Taking a medical history and selecting the right tests are key to getting a good diagnosis.”
— American College of Allergy, Asthma & Immunology
What the skin prick test actually feels like
A plastic applicator, not a syringe
Skin prick testing places a small amount of an allergen just under the surface of the skin, usually on the forearm or the upper back. The applicator is plastic and it barely breaks the surface. Most patients describe a scratch or a firm press. Children tend to get through it more easily than their parents expect, and that is usually because the parent walked in picturing a syringe.
The fifteen minutes you spend waiting
Once the panel is on, the waiting is the test. If you are allergic to something on it, a raised, itchy bump appears at that spot within about fifteen minutes. Nothing happens where you are not allergic. You stay in the room for that quarter of an hour, and you will usually see the answer developing before anyone reads it to you.
The itch is the result
Itching means the panel is doing its job, and it fades once the test is cleaned off. It is the least comfortable part of the appointment. Say something if it goes beyond an itch, because that is worth knowing and it is easy to settle in the room.
What to do in the week before
The first of these matters far more than the rest, because it is the one that can invalidate the whole test.
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- Ask us which medicines to pause. Antihistamines suppress the exact reaction the test is looking for, so a panel run while they are in your system can read negative when you are genuinely allergic. Call ahead and ask what to stop and how far in advance. Never stop a prescribed medicine on your own.
- Write down when the symptoms happen. A note on your phone covering the past few weeks beats trying to reconstruct it in the room. The month, the time of day, and what you were doing are the three most useful details.
- Bring your full medication list. Include the over the counter ones and anything you only take occasionally.
- Wear sleeves that move. Testing usually happens on the forearm or the upper back, so a short sleeve or a loose top saves everyone time.
- Leave room in your day. Between the history, the panel and the waiting, this is not an appointment to squeeze against a hard stop.
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When we use a blood test instead
We test with both skin and blood, and which one we use depends on your symptoms and your history. Blood testing is the route when skin testing is not practical, for example when a skin condition covers the area we would test, or when you take a medication you should not come off.
Blood is drawn the usual way and the results come back from the lab rather than appearing while you wait. It answers the same question, a few days later.
Reading your results the same day
With skin testing you go through the results in the same appointment. We look at what reacted, what did not, and how both line up with the history you gave at the start. A bump on the panel is not automatically the thing making you miserable, which is why the two halves of the visit get read together.
A clear panel is a real result too. If nothing reacts, allergy is ruled out as the cause and we can look at what else produces the same symptoms, instead of treating the wrong condition for months. We covered that case on its own in what a negative allergy test actually means.
You leave with a plan, not a list
The point of testing is what comes after it. Avoiding “something in the air” is impossible, while avoiding a named trigger is a plan you can follow. Named triggers are also what immunotherapy is built from, since the treatment is made up from your own results.
If your symptoms are persistent, seasonal, or have not responded to what you have already tried, testing is usually the right next step. Read more about how we test and what we test for, or request an appointment and we will call you to get it scheduled.
