Do you also experience itching, redness, and difficulty breathing when you eat certain foods, touch things like pollen, or use certain types of soap? If so, you may have an allergy to something. So, an important test to find out exactly what you are allergic to is called an allergy skin test . Let's talk about this in detail today, okay?
What is an Allergy Skin Test?
Simply put, this is a test that doctors do to find out exactly what is harmful to your body, that is, what you are allergic to. Our body has an immune system . This system protects us from diseases. But sometimes, when things that are actually harmless to us, for example, certain foods, dust, pollen, etc., enter our body, this immune system recognizes them as an enemy and responds. That is what we call an allergy.
So, in this skin test, they put a very small amount of something that they think you might be allergic to, called an ``allergen,'' on your skin. Then, after a while, the doctor checks to see what kind of reaction occurs in those areas. Based on that reaction, they decide what you are allergic to.
Are there different types of allergy skin tests?
Yes, there are three main types of allergy skin tests. They are:
- Skin Prick Test (sometimes called a Scratch Test)
- Intradermal Test
- Patch Test
We'll talk about each of these in detail later.
When is an allergy skin test done?
If you have frequent allergy symptoms (think itchy skin, red eyes, runny nose) or if you have asthma , a doctor may recommend this test. This is because sometimes these allergies can worsen asthma symptoms and trigger asthma attacks.
Another important point is that if you have ever had a severe allergic reaction, such as an anaphylactic reaction , this test is also very important to find the cause. Anaphylaxis is a severe condition that occurs suddenly, makes it difficult to breathe, and can be life-threatening. Therefore, you need to seek medical attention immediately.
How accurate is this allergy skin test?
To be honest, no allergy skin test is 100% accurate. However, if an experienced doctor, an allergist , performs these tests, the results are much more reliable. They will review your medical history and, if necessary, conduct further tests to arrive at the most accurate conclusion.
What should you expect before an allergy skin test? (How to prepare?)
Before you have an allergy skin test, you will need to see a doctor. He or she will ask you about your symptoms and may perform a physical exam. They may also ask you questions about the foods you eat, medications you take, skin care products you use, and pets you live with. They will also give you advice on what to do before the test. Some of these things include:
- On the day of the test, do not apply any cosmetics (such as lotions or creams) to the area of skin being tested.
- Some medications, especially antihistamines (allergy pills), may need to be stopped a few days before the test. Your doctor will tell you exactly what to do about this.
- If there is hair on the area of the skin where the test will be performed, you will be asked to remove it (shave it) either the night before the test or the morning of the test.
- Dress in a way that makes it easy for the doctor to examine you. For example, a shirt with buttons down the front or a sleeveless blouse is best.
- If your hair is longer than your shoulders, they say you can tie it up or hide it under a hat.
Can I shower before or after the test?
Yes, you can shower before the allergy skin test. But remember, do not apply any cosmetics to the areas where the test will be performed.
However, if you are doing a patch test , you cannot bathe, swim, or do anything that causes sweating for a few days after it. Your doctor will give you specific instructions about this.
What are these three types of allergy skin tests? How are they done?
As we mentioned earlier, there are three types of allergy skin tests. Before each test, the doctor will first clean the area of skin that will be tested with iodine or alcohol. This will reduce the risk of infection. This test is usually done on the front of your arm (forehead) or the upper part of your back. Sometimes, especially for young children, the doctor may also apply a numbing cream (`(Numbing Cream)`).
Now let's see what these types of tests are and how they are done.
1. Skin Prick Test (Skin Prick Test)
This is the most common type of allergy skin test. It involves exposing your skin to a very small amount of the substance you think you may be allergic to. It is used to detect allergies to things in the air (such as pollen, dust, mold, animal dander), foods, etc. It is also used as a preliminary test to detect allergies to insect stings (such as bees, wasps), and medications such as penicillin, and is then used to go on to an ``Intradermal Test'' if necessary.
How to do it:
The doctor will first make small marks on your arm or back with a pen to identify the `allergen` that will be applied to each spot. Then, using a very thin needle (a ``Lancet``), the skin surface is pricked very slightly at the marked spots. As soon as the prick is made, a small amount of the substance that can cause allergies is injected into the skin. This is not very painful, but it feels like a small sting, like being bitten by an ant.
Some doctors place drops of the substance that may cause an allergy on the skin surface and then slowly scrape it with a ``(Lancet).'' Then the substance enters the skin through the scratch.
Along with this, the doctor will apply two other patches of your skin, a ``Positive Control'' and a ``Negative Control'' . These are used to help compare the results. The ``Positive Control'' contains a ``Histamine solution'' . This causes a small swelling, redness, and itching (a ``Wheal'') on the skin as soon as it is applied. The ``Negative Control'' contains a ``Saline solution'' . This usually does not cause any reaction (a ``Wheal'').
After doing this, you wait about 15 minutes. After that, the doctor will measure the swelling and red spots on the skin with a caliper.
This skin prick test usually takes less than an hour to perform.
2. Intradermal Test
In this test, the doctor uses a very small needle to inject a small amount of the substance you may be allergic to into the top layer of your skin, the epidermis . This test is done if the results of a previous skin prick test are unclear or negative, to check for allergies to things in the air, medications, or insect stings (such as bees, ants, wasps).
How to do it:
First, the doctor will mark your hand with a pen for the relevant allergens. After that, this test can be done in two stages.
In the first stage, a small amount of the allergen is injected under the skin at the marked areas. After waiting for about 15 minutes, the skin is monitored for any swelling (`(wheal)`) or color changes.
- If you test positive for an environmental allergen, you will not need to do another intradermal test.
- If you test negative for an environmental allergen, it means you are not allergic to it and no further testing is needed.
- If a drug test comes back negative, you may be able to go for a second intradermal test.
- If the test for an insecticide is negative, three more rounds of intradermal testing will be required. The concentration of the substance is gradually increased in each round.
In the second stage (if necessary), a slightly stronger solution of the ``allergens'' that previously gave ``negative'' results is injected. Then, they wait another 10 minutes and measure the reaction again.
This `(Intradermal Test)` is not very painful. Many people say that it is less painful than the skin prick test. Depending on the number of `(Intradermal Test)` you have to do, this test can take about an hour and a half to complete.
3. Patch Test
In this test, the doctor applies plaster-like patches containing substances that you may be allergic to to your skin. This mainly detects the things that cause contact dermatitis . That is, allergies that occur when certain things come into contact with your skin.
How to do it:
The doctor will first ask you about the soaps, lotions, makeup, and jewelry you use. Then, they will make patches containing the substances you think you might be allergic to and stick them on your back. These patches should be left on for about two to four days. Then, the doctor will remove the patches and check to see if there is an allergic reaction. Based on this, they will make a list of the things you are allergic to and recommend products that are safe for you to use.
Imagine, whenever Samantha uses a new brand of soap, she gets little blisters all over her body and starts scratching. It was only after the doctor did a patch test that he discovered that Samantha was allergic to a fragrance in the soap.
What happens after an allergy skin test?
Depending on the severity of your allergy, the wheals may disappear within a few minutes or may last for several days. You may also experience other allergy symptoms, such as watery eyes, a stuffy nose, and sneezing. Your doctor will tell you when you can start taking your allergy medicine again.
Are there any risks with this test?
Most of the time, these tests are not very risky. However, very rarely , a severe anaphylactic reaction to an allergen can occur during the test. In such a case, the doctor can recognize it and quickly treat it with an epinephrine injection . So, there is nothing to worry about, you are on the safe side.
When will the test results be available?
In most cases, you can get the results of a skin prick test or an intradermal test right after the test is done, while you're still in the doctor's office. It takes about four days to get the results of a patch test.
What do allergy skin test results say?
You can get two types of results from an allergy skin test:
- Positive: A positive result means you are allergic to a substance. The larger the wheal, the more sensitive you are to that substance.
- Negative: A negative result means you are not allergic to that substance.
If you have an allergy... (Positive Result)
If your doctor confirms that you have an allergy, the two of you will work together to develop a treatment plan that is right for you. This plan may include:
- Avoiding allergens: The best thing to do is to stay away from those things as much as possible.
- Taking medication for allergies: Using the medications prescribed by the doctor.
- Taking allergy shots: This is a long-term treatment.
- Carrying an epinephrine auto-injector (EpiPen®): This is very important for people with severe allergies.
- It's a good idea to wear a medical alert bracelet with information about your allergies, or to carry a card with you.
- Having information about your food allergies included in your phone's medical emergency settings or in an app.
Can false-positive/false-negative results sometimes occur?
Yes, we've already said that allergy skin tests aren't always 100% accurate.
A ``false-positive`` result means that even though you react to a substance in the test, you have no reaction to that substance in everyday life.
A ``false-negative`` result means that you do not react to a substance in the test, but you react to that substance in everyday life.
If your doctor has doubts about the test results, he or she may recommend further testing.
What are the best times to see a doctor?
If you have severe allergy symptoms that are interfering with your daily life, it's important to see a doctor. They can perform allergy skin tests, determine what allergies you have, and help you develop a treatment plan that's right for you.
If you continue to have symptoms after getting an allergy skin test and finding out you have an allergy, let your doctor know so he or she can do more tests.
Is there insurance coverage for these tests?
It's best to talk to your doctor about this. Coverage can vary depending on your insurance policy, how much your doctor charges for these tests, and where you get treatment. Your doctor may refer you to a patient financial coordinator, who can give you a rough idea of how much your treatment will cost.
Finally, the most important thing (Take-Home Message)
Now you understand what an allergy is and the skin tests that are used to detect it. Allergies occur when our immune system overreacts to certain 'allergens'. These reactions can sometimes be as minor as a sneeze or an itch, or they can be severe enough to be life-threatening.
So, an allergy skin test is a very important test that helps you find out exactly what you are allergic to. Your doctor will recommend the right test for you based on your symptoms and what you think you may be allergic to. He or she will also help you develop the best treatment plan. So, if you have allergy symptoms, don't be afraid to see a doctor and talk about it.
I hope you find this information useful!
` Allergy, skin test, skin tests, immunization, allergen, diagnosis
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