An allergy test helps identify allergens that trigger an allergic reaction, thereby significantly improving a person’s quality of life.

Types of Allergy Tests

Allergy testing is a clinical method used to identify specific substances (allergens) that trigger allergic reactions in the body. These tests are performed by trained dermatologists and are helpful for those with chronic or unexplained symptoms affecting the skin, respiratory tract or digestion.

There are two commonly used tests:

Skin Prick Test (SPT) — this is used for detecting immediate-type (IgE-mediated) allergies such as food, dust mites or pollen.
Patch Test — this test is used for identifying delayed allergic reactions, such as allergic contact dermatitis (link to skin allergy test) caused by metals, preservatives and fragrances.

How does Allergy Testing work?

The test helps identify substances that trigger allergic reactions in your body. By exposing the skin to small, controlled amounts of allergens, a dermatologist (link to doctors page) can observe how your immune system reacts. This information is key to diagnosing allergies accurately and tailoring treatment or avoidance strategies to your needs.

Skin Prick Test (SPT) – used to detect IgE-mediated allergic responses

How it is done	Small drops of common allergens, such as dust mites or peanuts, are placed on the skin. It is usually placed on the forearm. Each drop is gently pricked using a tiny lancet to allow the allergen to enter the skin surface.
What happens next	If you are allergic, a small itchy bump (like a mosquito bite) may appear at the site within 15 to 20 minutes.
Best for	Environmental allergens, such as pollen, dust, food allergies, insect venom and some drug reactions.
Note	You will likely be asked to avoid antihistamines 5 to 7 days beforehand. This is because they can suppress the reaction.

Patch Test – used to detect non-IgE-mediated, particularly allergic contact dermatitis

How it is done	Adhesive patches containing tiny amounts of common allergens, like metals, fragrances or preservatives, are applied to your upper back.
What happens next	Patches are left on for 48 hours. You will return for 2 separate readings within a week to check for delayed skin reactions, such as redness, bumps or blisters.
Best for	Identifying contact allergens in cases of recurrent rashes or eczema (link to adult eczema page) that flare with product use or environmental exposure.

What are the benefits of Allergy Testing?

Understanding what triggers your allergy is the first step to lasting relief. Many people live with unexplained symptoms for years without knowing what is behind them. This can lead to frustration, ineffective treatments or lifestyle limitations.

The test offers:

Avoidance — empowers you to make informed choices and reduce future flare-ups.
Clarity — identifies the actual cause of your allergic reactions.
Peace of mind — replaces guesswork with facts, which can significantly reduce anxiety and uncertainty.
Personalisation — helps doctors tailor treatment, skincare or dietary plans specifically to your needs.
Prevention — early diagnosis helps prevent long-term inflammation and complications like chronic eczema or asthma.

What allergies can Allergy Testing detect?

Skin prick and patch tests can detect a wide range of common allergens. A dermatologist will select allergens based on your history, lifestyle and symptoms.

ALLERGEN	EXAMPLE
Via SPT
Environmental Allergens	Dust mites, which are common in bedding, curtains, and soft furnishings Mould spores Pet dander, such as cats and dogs Pollen from flowers, trees, and grasses
Food Allergens	Dairy Eggs Peanuts and tree nuts Shellfish Soy and wheat
Via Patch Test
Contact Allergens	Fragrances in personal care or cleaning products Hair dye chemicals Metals, such as nickel, jewellery and mobile phones Preservatives in skincare or cosmetics Rubber or latex
Others	Insect venom, such as from bee or wasp stings Certain drugs, such as penicillin

What to expect before, during and after Allergy Testing

Undergoing allergy testing can feel daunting, especially if you are unsure of what the process involves. Knowing what to expect at each stage can help reduce anxiety and ensure accurate results.

Generally, the test consists of the following steps:

Before Testing

Medication review – for skin prick tests, you may be asked to stop antihistamines 5to 7 days before testing. This is because they can suppress allergic responses. However, always check with a dermatologist before stopping any medication.
Skincare guidelines – avoid applying creams, moisturisers or steroid ointments on the test area for a few days before testing.
Medical history discussion – a dermatologist will take a detailed history of your symptoms, lifestyle, known allergies and skincare or dietary habits to tailor the test to your needs.

During Testing

Skin Prick Test (SPT)

It takes about 20 to 30 minutes.
Small drops of allergens are placed on your skin and gently pricked with a lancet.
You will wait about 15 to 20 minutes for reactions, such as a small bump, redness or itchiness.
The test is generally well tolerated and supervised by trained staff.

Patch Test

It takes a few minutes to apply, but patches remain on your skin for 48 hours.
Applied to your upper back using hypoallergenic adhesive patches containing specific allergens.
You must keep the area dry and undisturbed. As such, it is best to avoid excessive movement, sweating or friction.
You will return after 48 for patch removal and undergo 2 readings within a week to observe any delayed reactions.

After Testing

Mild irritation at test sites is common and usually settles quickly.
Avoid scratching the test areas to prevent infection or false results.
A dermatologist will interpret the results and explain what they mean in the context of your symptoms.
You will receive personalised advice on how to manage or avoid your triggers and whether further testing or treatment is needed.

What results can I expect from an Allergy Test?

Your test results will be discussed in the context of your symptoms. Interpretation is done holistically by a dermatologist, such as:

TEST RESULT	MEANING	NEXT STEPS
Positive skin reaction	Your immune system has responded to this allergen	Avoid the substance Treatment and education will be tailored accordingly
Negative result	No allergic response detected to tested allergens	Other causes, such as irritants and intolerances, may be considered
Mixed/unclear result	Mild reaction or inconsistent results	May need further tests or close symptom tracking
Multiple positive allergens	Sensitisation to various allergens	A dermatologist will help prioritise and develop a stepwise management plan

How many sessions of Allergy Test do I need?

Most allergy tests only take a few clinic visits. An SPT is usually done in one session, with results ready in about 30 minutes. If you need to test for many allergens or have complex symptoms, a dermatologist may suggest more sessions for extra testing.

Patch Testing takes longer. It requires 2 to 3 visits over one week as per below:

Visit 1 – patches are applied
Visit 2 (after 48 hours) – patches are removed
Visit 3 (5 – 7 days later) – skin is checked for delayed reactions

Sometimes, the dermatologist may ask you to come back for extra checks if new reactions appear or further interpretation is needed.

A skin patch can help determine triggers for contact dermatitis.

Summary

Living with allergy symptoms can be frustrating, especially when you do not know what is causing them. If you keep getting rashes, a blocked nose, or food reactions, it may be due to an allergy. Finding the exact trigger is the first step to managing your symptoms.

Allergy testing takes the guesswork out. With the right diagnosis, you can make smarter choices, avoid unnecessary restrictions and finally get relief from symptoms that may have been affecting your quality of life for years.

If you have been struggling with unexplained allergies or chronic skin issues, we encourage you to book a consultation with our clinical team at Dermatology Collective. With a little guidance and the right testing, a clearer, more comfortable life is entirely possible.

Frequently Asked Questions (FAQs)

Is allergy testing painful?

Skin prick tests feel like a mild scratch and are usually well tolerated. Meanwhile, patch tests are non-invasive and painless, though mild itching can occur.

Can children undergo allergy testing?

Yes, skin prick tests are safe and commonly done in children over 6 months old. However, patch tests are typically performed from the age of 6 years old and above.

What if my test is negative but I still have symptoms?

Allergy testing is one part of a full clinical assessment. Some rashes may not be caused by an allergy. But, our dermatologist will explain the results and outcomes further.

Will I need allergy testing again in the future?

Usually not unless new or unexplained symptoms develop. Allergies can change over time, particularly in young children or with ongoing exposure.

Is there a blood test alternative?

Yes, specific IgE blood tests are sometimes used, particularly when skin tests cannot be performed (due to skin conditions or medications). However, they may be less sensitive and more expensive.