Considering An Allergy Test In Singapore? What Are Your Options?

What Is An Allergy Test In Singapore?

There are several different types of allergy testing procedures, including

Allergy skin prick test (SPT)
Skin patch tests
Blood allergy tests (RAST blood test / ELISA)
Food elimination diets

The results of allergy testing can help to guide the development of an appropriate treatment plan for the individual. Allergy testing can help diagnose an allergy and guide allergy treatment decisions. It is important to note that allergy tests are not always 100% accurate; and it is important to work with a doctor or allergist to interpret the allergy test results together with your allergy symptoms and develop a suitable treatment plan.

Why Should I Get Tested For Allergies?

If you’re experiencing symptoms of allergic rhinitis such as itchy eyes, sneezing, nasal congestion, or skin rashes, you may want to consider getting tested for allergies. Here are a few reasons why an allergen test to diagnose allergies may be beneficial:

Identifying triggers: Allergy testing can help identify the particular allergens (e.g. dust mites), or particular food that cause symptoms, which can allow you to avoid them and minimize allergic symptoms.
Better treatment: Once you know what you’re allergic to, it may be easier to take the appropriate precautions to manage your allergies. This may include prescription medications, immunotherapy, or lifestyle changes.
Preventing complications: Food allergy can lead to serious complications, such as anaphylaxis, a severe reaction that can be life-threatening. By identifying your allergens and taking steps to avoid them, you can reduce your risk of developing complications.
Improved quality of life: Allergies, especially allergic rhinitis, can be disruptive to your daily life, affecting your ability to work, sleep, and enjoy activities. By getting tested and managing your allergies, you can alleviate allergic symptoms and improve your quality of life..

Skin Prick Tests

A skin prick test, also known as a puncture or scratch test, is a type of allergy test that is used to identify specific allergens that may be causing an allergic reaction.

The test is performed by applying a small amount of standardized allergen extracts to the skin, usually on the arm or back, and then making a small prick or scratch in the skin to allow the allergen to enter. If the individual is allergic to the allergen, a reaction to the skin prick test will occur, resulting in a raised, red, itchy bump (a wheal) appearing at the site of the prick or scratch within 15-20 minutes. The size of the wheal is measured and compared to a positive control (histamine) and negative control (distilled water) to determine how sensitive the individual is to the allergen. A negative skin prick test may result if the individual being tested has taken antihistamines or cough/cold preparations up to 7 days before the test.

A skin prick test is most useful for diagnosing aero-allergens (substances in the air which can cause allergies) such as dust mites droppings, pollen, mold and others, that cause nasal allergies (allergic rhinitis) and asthma. In certain cases, the skin prick test may also be used to diagnose food allergy.

Skin Patch Tests

A skin patch test is a form of allergy testing that is used to identify allergens that may be causing a skin condition or skin allergy symptoms (contact dermatitis). The allergy test is performed by applying small patches containing the allergens in question to the skin, usually on the upper back, and then leaving the patches in place for 48 hours. The individual is then evaluated for any skin allergic reaction, such as redness, itching, or blistering, at the site of the patches.

Patch testing is particularly useful for identifying allergens that cause delayed-type hypersensitivity reactions, such as those that cause contact dermatitis.

Delayed-type hypersensitivity reactions are when our body gets upset with something and it takes a little while for the upset to show. For example, when you eat food that has gone bad, your stomach doesn’t get upset right away, but it takes a little while. The same thing happens with our skin, it takes a little while for it to get upset after we come in contact with something it doesn’t like.

For example, if you are allergic to grass when you touch it, your skin may not get red or itchy right away, it could take a day or two for the reaction to happen. This is different from other types of allergic reactions such as peanut allergies. Peanut allergies usually present as an immediate-type reaction – if patients who are are allergic to peanuts come into contact with peanuts, they may experience immediate allergic reactions.

Common allergens that are tested include nickel, fragrances, preservatives, rubber and certain medications. The test is usually read after 48 and 72 hours. Positive reactions will show redness, itching, or blistering at the site of the patch.

Blood Test For Allergies

A blood allergy test, also known as a radioallergosorbent test (RAST) blood test, or ImmunoCAP test, is a type of allergy test that measures the level of immunoglobulin E (IgE) antibodies in the blood in response to specific allergens. These IgE antibodies are produced by the immune system in response to allergens and play a key role in allergic reactions.

The IgE antibodies blood test are performed by taking a blood sample from the individual and then measuring the level of IgE antibodies in the sample, that are specific to the allergens being tested. The results of the test are typically reported as a number, that indicates the level of IgE antibodies present in the blood. High levels of IgE antibodies in the blood can indicate that the individual is allergic to the allergen being tested, while low levels may indicate that the individual is not allergic.

This form of allergy testing can elicit the presence of both aero-allergens such as dust mites droppings, pollen, and mold; and assist in food allergy testing. A small blood sample can be tested for 50-60 allergens, if necessary. Results take approximately 5-7 working days before they are available.

Food Elimination Diets

A food elimination diet is a type of food allergy testing, that is used to identify food allergies / food sensitivities. The diet involves eliminating certain foods or food groups that are suspected of causing food allergy or an adverse reaction and then reintroducing them one at a time to see if allergy symptoms reappear.

The process typically starts by eliminating the most common food allergens, such as milk, eggs, peanuts, tree nuts, fish, shellfish, soy, and wheat, and then gradually reintroducing them into the diet after a period of time, usually two to four weeks. The patient is closely monitored for any food intolerance or allergic reaction such as hives, itching, swelling, shortness of breath, or gastrointestinal problems. Reintroducing the food one at a time is done to identify which specific food allergies are causing the symptoms. This method of discerning food allergies is also known as “challenge and re-challenge” and it is usually done under the guidance of a healthcare professional such as a dietitian or allergist to ensure safety and accuracy.

Frequently Asked Questions

References:

Healthline | Allergy Testing

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