Allergy testing is an examination performed by an allergy specialist to determine if your body has an allergic reaction to any known substance. The examination can be conducted through a skin prick test or blood test. Your immune system is your body's natural defence, and allergies occur when this system overreacts to something in the environment.
For example, pollen may cause your immune system to overreact, leading to:
- Blocked sinuses
- Runny nose
- Sneezing
- Watery or itchy eyes
- Coughing or wheezing
Different Kinds of Allergens
Allergens are substances that may lead to an allergic reaction. There are three main types of allergens:
1. Inhaled Allergens
These affect the body after coming into contact with the membranes of the nostrils, throat, or lungs. Pollen is the most common form of inhaled allergen.
2. Ingested Allergens
These are present in certain types of foods such as:
- Peanuts
- Seafood
- Soy
- Dairy products
- Eggs
3. Contact Allergens
These come into contact with the skin and cause reactions like rashes and itching. Common examples include poison ivy, latex, and certain metals like nickel.
How it works: Allergy tests expose you to small amounts of specific allergens and then record your body's reaction.
Types of Allergy Tests
Several tests are available to determine whether you have allergies. Your healthcare provider will recommend the right method based on your symptoms and suspected allergens.
🔬 Skin Tests
Skin tests can detect several potential allergens including food-related, contact, and airborne allergens. There are three main types:
Scratch Test (Skin Prick Test)
The doctor will typically try a scratch test first:
- An allergen is placed in a liquid solution
- The liquid is placed on your skin
- A special tool punctures the allergen lightly into the skin surface
- You are monitored for skin reactions
If there is swelling, redness, or itchiness at the test site, you are allergic to that specific allergen.
Intradermal Skin Test
If the scratch test results are uncertain, an intradermal skin test may be performed. This involves injecting a small amount of allergen into your skin's dermis layer. This test checks for allergies to:
- Airborne irritants
- Insect stings
- Medications
Patch Test
This test uses adhesive patches loaded with suspected allergens placed on your skin. It's primarily used to evaluate allergic contact dermatitis.
- Patches remain on your body for 48 hours
- Reassessed at 72-96 hours after application
🩸 Blood Tests
If you might have a severe allergic reaction to skin testing, or cannot undergo it, a blood test may be recommended instead.
ImmunoCAP Test: Also known as IgE testing, this blood test detects the presence of IgE antibodies to specific allergens. Your blood sample is taken and sent to a laboratory for analysis.
🍎 Challenge Tests
Conducted under strict medical supervision, challenge tests are used for suspected food or drug allergies. You ingest a small amount of the allergen while an allergist monitors for reactions. If anaphylaxis occurs, an epinephrine injection is immediately administered.
How to Prepare for Allergy Testing
Before undergoing an allergy test, your doctor will ask about your family history, lifestyle changes, and current symptoms. You may be asked to stop taking certain medications before the test as they can affect results:
- ✖️ Antihistamines (prescription and over-the-counter)
- ✖️ Heartburn medications like famotidine
- ✖️ Benzodiazepines (lorazepam, diazepam)
- ✖️ Tricyclic antidepressants (amitriptyline)
- ✖️ Systemic corticosteroids (for patch tests)
Why You Need Allergy Skin Tests
Allergy skin tests help diagnose various allergic conditions including:
- ✅ Allergic asthma
- ✅ Bee venom allergy
- ✅ Dermatitis or eczema
- ✅ Food allergies
- ✅ Hay fever (allergic rhinitis)
- ✅ Penicillin allergy
Skin tests are safe for children and adults of all ages, including infants.
When Should You Get Tested for Allergies?
You should visit an allergist if:
- Your allergies cause symptoms such as nasal congestion, chronic sinus infections, or difficulty breathing
- You suffer from hay fever or other allergy symptoms for several months throughout the year
- Over-the-counter medications aren't providing relief
- Your symptoms are affecting your quality of life
Understanding Your Allergy Test Results
✅ Positive Result
You are allergic to a specific substance. Even when results correctly indicate an allergy, it does not mean you will react to that allergen every time.
Note: A false positive is possible with blood (IgE) tests — this means results indicate an allergy when you don't actually have one.
❌ Negative Result
You are not allergic to that substance. False negative results are unusual but can occur.
Treatment Options for Allergies
Based on your allergy test results, your healthcare provider may suggest one or more of these approaches:
1. Reduce Exposure to Allergens
Avoid substances that cause severe reactions, such as certain food items or latex.
2. Daily Allergy Medications
Antihistamines can help reduce or prevent allergic rhinitis and other symptoms.
3. Allergy Shots (Immunotherapy)
This treatment can reduce the immune system's response to allergens like pet dander. Benefits include:
- Treatment duration: 3-5 years
- Long-lasting relief even after the treatment series is completed
- Reduces sensitivity over time
4. Carry a Medical Alert Card
A medical alert card informs others about your severe allergy and the risk of anaphylactic response to bee stings, peanuts, or other allergens.
5. Epinephrine Injection (EpiPen)
If you're at risk for anaphylactic allergic reactions, always carry this life-saving medication with you.
Does Allergy Testing Cause Pain?
Allergy skin tests are not painful. The testing uses needles that only penetrate the surface of your skin. You will not bleed or feel more than mild discomfort.
Allergic reactions may range from irritating congestion to life-threatening shock. With the help of allergy tests, you can detect substances that cause such reactions and take appropriate steps for relief.
🏥 Book Your Allergy Test at Walk In Clinic London
Our healthcare providers at the private walk-in clinic will select the right test for you based on your symptoms and possible allergy triggers. If you're suffering from allergies, take the first step towards getting relief.