An allergy is an adverse reaction from an immune reaction to something that just the touch of your body, breathe or swallow. These reactions include sneezing, wheezing, coughing, itching, skin rash, abdominal pain, diarrhea, or even lower blood pressure, can cause dizziness or go out. With proper management and education, people with allergies can lead a healthy, normal life. Your immune system controls the body’s way of self-defense.
So how can you make sure that allergens must be responsible for your symptoms? Allergy test, combined with a physical examination and medical history, can provide accurate information about what you are, and what you do not have allergy. You do not have to avoid contact with these animals if the test shows allergy to dust mite allergies but not to animal fur.
Skin-test has shown its useful functions to many types of allergy. Allergy skin testing provides valuable information about how the body reacts to different substances that you can become allergic, known as “allergens”.
These tests use extracts (a concentrated liquid form) of common allergens such as pollen, mold, dust mites, animal fur, and food. Reactions to this test help doctors can tell you are allergic to something. When you have allergies, your immune system will produce antibodies and chemicals to set off against the trigger.
- General knowledge of test skin
- The types of skin testing
- How can the skin test be performed?
- The importance of skin test
- Preparation for the safe skin tests
- What should you do with the results of the skin test?
1.General knowledge of test skin
Skin testing is a method that doctors use to see if a patient’s exposure to specific substances that provoke an allergic response. Immediately called skin test is used to diagnose the allergy occurs rapidly after exposure to allergens. Allergies occur several hours or more after exposure are not usually identified with the skin test
Check the skin for allergic disorders has been around since the year 1860. This is a test performed on the skin to identify the allergen (allergen) which is the start of an allergic response. Today, prick or puncture tests are often used by allergies such as those to support the diagnosis. If the results of the magnet or puncture tests are negative, they can be followed by tests in the skin, which provides for allergies more details about what caused the basic symptoms.
In skin allergy test, your skin is exposed to the suspected allergens (allergens) and then is observed for signs of an allergic response.
The types of skin testing
- Testing Skin Prick
A skin prick test, also called a test puncture or scratch, check for allergic reactions up to 40 different substances simultaneously. This test is usually performed to identify allergies to pollen, mold, pet dander, dust and other types of food. Skin prick test is the most convenient method of allergy testing. When the results within 20 minutes, this allows you to discuss the results with your doctor at the time of inspection. Skin may be numbered corresponding to the allergen. The first skin is cleaned with alcohol. After cleaning the test site with alcohol, the nurse withdraws a small spot on your skin and applies a drop of allergen next to each brand. Then prick, puncture, break or scratched the top layer of skin below the drops. This tattoo is allowed to seep into the skin extract.
If you are allergic to the allergens tested, a small itch Department (wheal) is surrounded by a red flame appears within 15-20 minutes.
Skin prick test is slightly uncomfortable (itching) but generally well tolerated, even young children. Itching and swelling typically local tapered over 1-2 hours. Many serious stretching or swelling can be treated with non-sedating antihistamine, an analgesic tablet and / or cold compresses. Sometimes people will feel dizzy or dazed and need to lie down. A doctor should be present to select the allergen, interpret the results and deal with any generalized allergic reaction that may rarely occur.
Antihistamine tablets / syrup or antihistamines may act like (such as some cold remedies and antidepressants) should not be used for 3-7 days before the test because they would interfere in the results of the test experience. You may also be advised to avoid moisturizer on your arms and on the day the test to reduce the likelihood of allergen extracts will run into each other.
Skin prick test has no value in the investigation of suspected reactions to aspirin, food additives, or irritants like smoke inhalation or perfume. This type of test used the needle (lancet) that barely penetrates the skin’s surface. You will not bleed or feel lighter, temporary discomfort.
- Skin Testing Needle
This type of skin testing is also known as a skin test or intradermal injection method. This method is more likely than the injection method for a positive response; However, these results are often more “false positives”.
After injecting of a small amount of allergen on the skin, the service providers of health care then watch for a reaction at the site. This test is more likely to be used to find out if you are allergic to bee venom or penicillin. Or it can be used if the skin prick is negative and suppliers still think you are allergic to the allergen.
- Patch Test
Patch test is a method to diagnose the cause of skin reactions occur after contact with the skin substances. Allergens can be affixed to the skin for 48 hours. The service providers of health care will look at this area in 72 to 96 hours.
In a patch test, your skin may be exposed to 20-30 extracted substances can cause contact dermatitis such as condoms, medicines, perfumes, preservatives, hair dyes, metal and plastic.
You wear the patch on your arm or back in 48 hours. During this time, you should avoid activities that cause showers and heavy sweating. Spot irritated skin patch may indicate an allergy. You should plan for an hour-long appointment if you have this type of skin test.
How can the skin test be performed?
The extracts from allergens such as grasses, trees, weeds and pollen; mold spores; animal hair; cockroach or dust mite debris; and certain foods are placed either on the skin or they are injected just below the skin’s surface. Depending on the history of a particular patient, there are about 10 to 50 different allergens tested.
Skin test is usually done in a doctor’s office. These tests detect delayed allergic reactions, which develop over a period of several days.
Skin test is fast, simple and relatively safe. They can be very useful in determining the specific cause of allergies. For both skin test, positive reactions usually appear within 20 minutes. If the skin reddens, and more importantly, if it blooms, then test is read as positive and allergy are considered probable.
The importance of skin test
The skin test is used to check for food allergies because of the high false-positive results, and the risk of causing a severe allergic response.
A skin test can be slightly uncomfortable, but most people say it does not hurt. Although you are exposed to things you may be allergic to, they are a very small amount.
Systemic reactions to allergy skin test are very rare, but please tell your doctor right away if you have:
- Light headedness
- Shortness of breath
- A widespread rash
- Difficulty swallowing
An allergy skin testing is widely used to help diagnose allergic diseases, including: Your doctor may require a skin allergy test if you have:
- The Hay fever (allergic rhinitis) and asthma is not well controlled with medication
- Hives and angioedema
- Food allergies
- Skin rash (dermatitis), in which the skin becomes red, painful, or swollen after exposure to the substance
- Penicillin allergy
- Venom allergies
- Allergic asthma
- Dermatitis (eczema)
- Food allergies
- Penicillin allergy
- Bee sting allergy
Preparation for the safe skin tests
Skin test is usually safe for adults and children of all ages, including infants. In certain cases, however, the skin test is not recommended.
Some medicines can affect the results, so your doctor will give you a list of medicines to avoid before the test. To be accurate, the skin allergy test required all antihistamines are completely out of your system. You should stop using all antihistamines 3-7 days before your test skin depending on the specific antihistamines you are using. However, you should continue to take any steroid nasal sprays and all kinds of asthma medications because these will not interfere with the skin-test.
If you cannot stop taking the medication, your doctor or your nurse can do a separate test to find out which drugs will hinder results. Before checking allergies, your doctor may advise against skin test if you:
- Too sensitive to any certain allergens
- Use any types of medicine that may affect the results of this skin testing.
- In skin conditions such as eczema or psoriasis, dermatographism that may cause test results unreliable.
- Illness; workplace; life style; diet
Your answers can help doctors determine allergies run in your family and if an allergic reaction most likely cause of your symptoms. Skin tests may cause very mild discomfort when the skin is injected. You may have symptoms such as itching, stuffy nose, watery red eyes or redness of skin if you are allergic to the chemicals in the test. In rare cases, people can have a systemic allergic reaction (called anaphylaxis), can be life-threatening. This usually only happens with the skin test. Doctor will be prepared to treat this serious reaction.
After your test: The doctor or nurse will clean any ink marks from the extracts and your skin with alcohol. You may need to use a mild cortisone cream to reduce itching.
If you receive a patch test, you will go home with ice on your skin. Do not get wet areas – no baths or swimming. When you go back to the doctor in a few days, he would consider adding to your skin.
Your doctor or your allergies will use your test results to come up with a treatment plan for you.
Risks can occur: The most common side effects of skin testing slightly swollen, red, itchy bumps (wheals). The wheals may be most noticeable in the time trial. In some people, however, the area of swelling, redness and itching can develop a few hours after the test and persist until a couple of days.
It is not usual but in some situations, patients can have a severe immediate allergic reaction, therefore the skin test must be performed in health office with appropriate emergency equipment and drugs.
What should you do with the results of the skin testing?
According to your reaction with the allergen extract placed under the skin, your doctor will determine whether it is the symptom of an allergic response. The size of the wheal and flare appearing on your skin area exposed with allergens shows approximately how much IgE allergy antibodies you’ve done with that allergen.
Normally, with a test injection, farming area must have at least three millimeters (about one-tenth of an inch) in order to indicate a positive response. With an intradermal test, a larger response is required.
A positive test only shows that you’ve taken the allergy IgE antibodies to the allergen. You should notice that the results of this skin testing are not always accurate definitely. It means that in some cases, you may not have allergy symptoms even though you are exposed to allergens, This is one of the reasons why the test results to your skin should be carefully correlated with your history by an allergy specialist to determine what you are really allergic.