Do you have allergies too? Let's learn everything about the Allergy Skin Test!

Does this happen to you sometimes? When you touch a little dust, you sneeze and sneeze, and a runny nose runs. When you eat food like shrimp or squid, your whole body itches and red bumps appear. Or when you come near a cat, your eyes become red and watery. If this happens to you often, the reason may be that your body is allergic to certain things, or as we all know, you are "allergic". So today we are going to talk about a very important test to find out exactly what this allergy is.

What exactly is an allergy skin test?

Simply put, this is a test your doctor does to find out exactly what you are allergic to. Our body's immune system is there to protect us from diseases. But sometimes, when it sees things that are actually harmless to the body (for example, pollen, dust, certain foods), this immune system overreacts. We call these allergens .

So, in this skin test, you put very small amounts of different allergens that you suspect you may be allergic to on your skin and see if your skin reacts to them. By looking at that reaction, the doctor can come to a conclusion about what you are allergic to.

Are there main types of allergy tests?

Yes, there are three main types of allergy skin tests. Your doctor will decide which test you need based on your symptoms and the nature of the suspected allergy.

When should this test be done?

There may be several reasons why your doctor might recommend this test.

• If you have frequent allergic symptoms: For example, if you constantly itch your skin for no reason, if you get rashes, if you sneeze, if your eyes get red.
• If you have asthma: Some allergens can make your asthma worse. So once you know what they are, it's easier to stay away from them and control your asthma.
• If you have had a severe allergic reaction: Some people can have a severe allergic reaction to something that makes them unable to breathe. We call this anaphylaxis . This is a life-threatening emergency. If this happens, this test is done to find out exactly what caused it.

How should you prepare before the test?

Before the test, the doctor will ask you a lot of questions about your symptoms, what you eat, what medications you take, what you apply to your skin, and whether you have any pets at home. Then, he will tell you a few things to do before the test.

• Do not apply anything to your skin: On the day of the test, do not apply any creams, lotions, or oils to the area where the test will be performed (usually the arm or back).
• You may need to stop taking some medications: You may be asked to stop taking allergy medications (e.g. antihistamines like Piritan) a few days before the test. This is because taking these medications can affect the test results. But don't do this on your own, just do what your doctor tells you to do, and only stop for the number of days he or she tells you.
• Hair removal: If there is a lot of hair in the test area, you will be asked to remove it the day before or the morning of the test.
• Wear comfortable clothing: Wear clothing that allows easy access to the testing location, such as a button-down shirt.

Let's learn in detail how to conduct the three types of tests.

Before performing any of these three tests, the doctor or nurse thoroughly cleans the area where the test will be performed with something like alcohol to prevent infection.

1. Skin Prick / Scratch Test

This is the most common test. A pen is used to mark small squares on the skin of your arm or back. Then, a drop of liquid from each suspected allergen is placed on the squares. Then, a very small, thin needle-like device called a lancet is used to make a small puncture through the drop of liquid into the skin. This does not hurt, but feels like a small prick, like being bitten by an ant.

In addition to these allergens, two other liquids are used.

• Positive control: This contains a chemical called histamine . When applied to anyone's skin, a small red bump appears. This is to check if your skin reacts normally.
• Negative control: This contains saline solution. There is no way for your skin to react to this. This is to make sure that your skin just turns red.

You need to wait about 15 minutes after doing all this. If you are allergic to something, the area will become red and slightly swollen, like a mosquito bite. We call it a wheal . After 15 minutes, the doctor will measure the size of the bumps and record the results.

2. Intradermal Test

This is a little more sensitive than the skin prick test. Here, the allergen solution is injected into the epidermis, the top layer of the skin, with a very small needle. This is also not very painful. This test is done when the results of the prick test are not clear, especially to check for allergies to medications and insect venom. In this test, the reaction is also measured after waiting about 15 minutes.

3. Patch Test

This test is used to detect contact dermatitis, which is a skin reaction caused by something coming into contact with the skin. For example, if you use a new type of soap and your skin breaks out in a rash, this test can help determine the cause.

This involves placing small patches (like plasters) on your back that contain chemicals that you suspect you may be allergic to (e.g., soaps, lotions, metals in jewelry). The patches should be left on for two to four days. During this time, the doctor will tell you not to get the area wet. This means not to shower or do any exercise that causes sweating. When you go back a few days later, the doctor will remove the patches and check your skin for any reactions (redness, rash).

What happens after the test? Are there any risks?

After the test, you may have small red bumps on the areas you were allergic to for a while. These will gradually disappear with scratching.

The biggest, but very rare, risk of this test is a severe allergic reaction, the aforementioned anaphylaxis .

How to understand the test results?

You can get the results of skin prick and intradermal tests on the same day, within a short time. It takes a few days to get the results of a patch test.

Sometimes the test results may not be 100% accurate. Even if the test shows that you are allergic, you may not have any problems with that substance in real life (false-positive) . Also, even if the test shows that you are not allergic, you may actually be allergic to that substance (false-negative) . Therefore, the doctor will consider the test results, your symptoms and medical history, and come to a final conclusion.

What if you are diagnosed with an allergy?

Your doctor will create a treatment plan that is right for you. It may include things like:

• Allergen avoidance: Advising you to stay as far away from things you are allergic to as possible.
• Medications: Prescribing medications to control allergic symptoms.
• Allergy shots: This treatment is used as a long-term solution for some people.
• Carry an EpiPen®: People with severe allergies (anaphylaxis) are advised to always carry an Epinephrine injection that they can inject themselves with in case of an emergency.
• A medical alert bracelet: You may be asked to wear a bracelet that says you have a severe allergy.

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