Allergy testing, this is what you should know

An allergy test is an examination procedure that aims to detect whether a patient's body has an allergic reaction to certain substances or substances (allergens). Allergy tests can be done in the form of blood tests or skin tests. This examination procedure is generally carried out by an allergic consultant doctor. Allergies occur when the immune system produces excessive reactions to allergens found in the surrounding environment. Allergic reactions produced by the body vary, ranging from mild symptoms to anaphylactic reactions that can be life-threatening. Mild allergic reactions that commonly occur include sneezing, nasal congestion, itching, and runny eyes and nose.

Types of substances that cause allergies (allergens)

Allergens are substances, substances, or substances that cause allergies. Generally, there are three types of allergens, namely:

• Inhale allergens. Allergens that can trigger allergic reactions in the body when inhaled and interact with the lining of the nose, throat, or lungs. Allergens that are classified as inhaled allergens include pollen, dust, and animal dander.
• Contact allergen. Allergens that can trigger allergic reactions in the body when interacting with the skin. Insect stings and chemicals, such as latex, are some examples of contact allergens.
• Gastrointestinal allergens. This type of allergen is commonly found in foods, such as nuts, seafood, or soy. In addition to food, drugs such as penicillin antibiotics, are also included in gastrointestinal allergens.

Indications of allergy testing

Allergies can occur to anyone, but are generally more prone to occur in children and people who have a family history of allergies, such as asthma or eczema. Allergy tests can be done through the skin or taking blood samples. But allergy testing through the skin is a more common method of examination. This test aims to detect the type of allergen that causes allergies in the patient's body. Allergy testing through the skin is carried out on someone who is suspected of having an allergy to certain substances (for example animal dander or food), which causes a person to suffer from allergic rhinitis, asthma, dermatitis, or swelling under the skin (angioedema). Warning Please be careful when testing for allergies through the skin under the following conditions:

• Patients under the age of 2 years. Consult your doctor first because allergy testing through the skin has a greater risk if done on children under the age of 2 years.
• Patients who are new or experiencing an allergic reaction, especially having anaphylactic reactions. Allergy testing through the skin should only be done 4-6 weeks after the patient has an anaphylactic reaction. This condition can cause inaccurate test results.
• Patients suffer from certain skin disorders, such as eczema or psoriasis. This skin condition can affect the structure of skin cells and cause allergic tests to be inaccurate. Allergy testing through the skin should be done under normal skin conditions.
• Patients with health problems, such as heart problems or asthma.
• Patients who are taking drugs that can affect the results of allergy tests, such as antihistamines and corticosteroids, as well as other drugs such as ranitidine, tricyclic antidepressants, and beta-blocker drugs.
• Elderly patients (> 65 years). Allergy skin testing done to elderly patients should be done carefully because the skin and body response tend to be more sensitive.

If allergy testing through the skin is not possible, the doctor will do an allergy test through a blood sample. This type of allergy test is generally safe, including in patients with skin disorders and children under the age of 2 years. Blood allergy testing is also safe for patients who are taking antihistamine drugs so that patients do not need to make special preparations before undergoing this allergy test. However, there are some drawbacks from blood allergy testing, including:

• The cost is more expensive than a skin allergy test.
• The process of analyzing blood samples takes a long time, so the results of tests generally only come out after a few days or a few weeks.
• Less sensitive than allergy testing through the skin because it cannot determine the type of allergen.

Before the Allergy Test

Before the patient has an allergy test, the doctor will check the patient's medical history. At this stage, the doctor will ask for a history of complaints, questions related to lifestyle and daily activities, and family health history, especially a history of allergies. After that, the doctor will do a physical examination to look for additional clues related to allergic signs. Your doctor may also recommend stopping certain medications 10 days before an allergy test. These types of medicines include:

• Antihistamine drug.
• Ulcer drugs, such as cimetidine and ranitidine.
• Omalizumab asthma medication.
• Tricyclic antidepressant drugs, such as amitriptyline.

Types and Allergy Test Procedures

There are several types of allergy tests that are generally done to determine allergens, including skin allergy tests, blood allergy tests, and elimination diets.

Allergy skin testing

• Skin prick test.

This is the most common type of allergy test. The following is an allergy testing procedure through a skin prick:
• The doctor will clean the patient's upper arm or forearm with alcohol.
• After cleaning, the doctor will mark the skin with a marker or pen.
• The doctor will drop a number of solutions (up to 10-12 drops) on each mark that has been made. The solution is a mixture of liquid and allergen. Each solution contains a different allergen.
• The doctor will prick the area of ​​the skin that has been dripped with a solution with a needle so thin that the allergen can get under the surface of the skin.
• The doctor will watch for signs of allergies that may appear on the skin. Allergic reactions will generally appear within 15-20 minutes.

• Intradermal skin test.

This skin test is done if the skin prick test shows negative results, but doctors still suspect that the patient has an allergy to an allergen. The following are intradermal skin test procedures:
• After the patient's skin is cleaned with alcohol, the doctor will inject a small amount of allergen into the skin layer.
• The doctor will monitor for allergic reactions that might appear on the patient's skin. Allergic reactions will generally appear within 15-20 minutes.

• Patch testing.

Patch testing is generally done to detect substances or allergens that cause skin irritation (contact dermatitis) in patients. The allergen can be metal, plastic or rubber. Following is the patch testing procedure:
• The doctor will clean the upper part of the patient's back with alcohol.
• After cleaning, the doctor will attach a type of adhesive that has been filled with 20-30 substances or allergens that cause contact dermatitis.
• After 2 days, the doctor will check whether there is an allergic reaction caused by one of the allergens attached.
• The doctor will re-examine it two days later to detect if there is a delayed allergic reaction.

Blood allergy test

Blood allergy testing is generally done if the patient is feared will experience a severe allergic reaction to the allergy test through the skin. Blood allergy testing is done by examining immunoglobulin E (IgE) in the blood. Immunoglobulin E (IgE) is an antibody produced by the immune system to fight substances that are considered a threat to the body. When the body experiences an allergic reaction, the amount of IgE will increase. The measured IgE can be the total number of IgE antibodies in the body (total IgE test) or the level of IgE antibody response to an allergen (specific IgE test). Blood allergy test is started by taking a blood sample, then the blood sample will be examined to a laboratory for analysis. The procedure for blood allergy testing generally takes less than 5 minutes, but it takes several days for the results of the test to come out.

Elimination Diet

Elimination diets are generally carried out to detect food allergies in patients. The elimination diet procedure is divided into two phases, namely:

• Elimination phase. This phase is done by avoiding the consumption of food that is suspected to be a trigger for allergic symptoms. Some foods that are generally avoided include nuts, milk, eggs and seafood. In this phase, the patient can detect whether allergy symptoms are caused by food or something else. The elimination phase lasts for 2-3 weeks.
• Reintroduction phase. This phase is done by consuming the type of food that was previously avoided slowly again. During the reintroduction phase, the patient or doctor can observe possible signs of allergies, such as rashes, flatulence, or shortness of breath. If these signs appear, the cause of the allergy has been identified and patients are advised to avoid consuming these types of food.

The entire process of elimination diet generally takes 5-6 weeks. Consult your doctor or nutritionist before going on an elimination diet. Too much eliminating eating can cause the body to lack nutrition.

After the Allergy Test

Allergy test results can be known in a matter of minutes to days. The results of allergy testing through the skin, namely puncture tests and intradermal skin tests, generally can be known in just minutes. The test results can be said to be positive when the skin becomes red, itchy, and small white spots appear around the test area. These white spots will disappear after a few hours. Test results are said to be negative when the skin remains in normal condition. This condition indicates that the patient does not have an allergy to any allergens. Blood allergy test results generally take several days to go through the analysis process in the laboratory. If the test results show the total IgE in the body is higher than the normal limit, then the patient may have an allergy. However, the total IgE test is considered less sensitive when compared to the allergy test through the skin, and the total IgE test does not reveal the type of allergen that causes the allergy. To find out, patients can run specific IgE tests. Once the cause of the allergy is identified, the doctor will determine an allergic treatment plan, including avoiding contact with allergens and drugs. Some steps that can be taken to prevent contact with allergens include:

• If you have food allergies, check the composition of packaged or canned foods before consuming them.
• Clean the bed and change the sheets or bedding regularly.
• Clean carpets regularly, or avoid using carpets, especially if you have pets.
• Keep the humidity inside the house with a good ventilation system.
• If possible, use air conditioning because it can reduce the development of mold and dust populations.
• Prevent pets from entering the bedroom and clean the pets regularly.

Complications of allergy testing

Every examination procedure generally has risks, including allergy testing. Some common side effects that may occur after an allergy test include:

• Itchy.
• Blushed skin.
• Swelling in the examination area.
• Small spots appear on the skin area
• Pain in the injection area.
• Minor bleeding at the injection site.

These mild side effects will generally disappear within hours or after a few days. The use of corticosteroid creams can be recommended to alleviate side effects. In rare cases, allergy tests can produce severe allergic reactions and require emergency medical procedures. One of them is anaphylaxis, which is a severe allergic reaction that can threaten a patient's life. Anaphylactic reactions are characterized by several signs and symptoms, including:

• Nausea, vomiting or diarrhea.
• Dizzy.
• Weak and fast heartbeat.
• Reactions to the skin, which include itching and reddened skin.
• Narrowing of the respiratory tract and swelling of the throat or tongue, which makes the patient difficult to breathe.

If an anaphylactic reaction occurs after leaving the hospital or arriving home, call your doctor immediately to get emergency treatment.