Intradermal Allergy Test: A Detailed Guide 

What is an Intradermal Allergy Test? 

An intradermal allergy test is a diagnostic procedure that helps identify allergies by injecting a small amount of an allergen just beneath the skin’s surface. It is often used when a skin prick test provides inconclusive results or when testing for specific allergens like insect venom or certain medications. 

How Does the Intradermal Allergy Test Work? 

The procedure involves three key steps: 

1. Injection: A tiny needle injects a small quantity of allergen solution into the dermis (the deeper layer of the skin). 
2. Monitoring: The injection site is observed for 15 to 30 minutes to check for any signs of a reaction, such as swelling or redness. 
3. Interpretation: The size of the raised bump (wheal) and surrounding redness (flare) are measured to determine whether an allergy is present. 

Allergens Commonly Tested 

• Medications: Antibiotics like penicillin, local anesthetics, and other drugs. 
• Insect Venom: Allergies to stinging insects, such as bees and wasps. 

Why Choose an Intradermal Test? 

An intradermal allergy test is typically chosen when: 

• A skin prick test yields negative results, but clinical suspicion remains high. 
• Higher sensitivity is required, especially for allergens like insect venom or certain drugs. 
• Precise, detailed results are necessary for accurate diagnosis. 

How is the Test Performed? 

1. Preparation: The healthcare provider cleans the test area, usually the forearm or upper arm. 
2. Injection: A small amount of allergen is injected under the skin using a tiny needle. 
3. Observation: The site is observed for any reaction over a period of 15 to 30 minutes. 

Understanding the Results 

• Positive Reaction: A raised bump (wheal) with surrounding redness (flare) indicates sensitivity to the allergen. 
• Negative Reaction: No significant change at the injection site suggests the absence of an allergy to the tested substance. 

Are There Any Risks? 

While generally safe, the test can cause: 

• Minor reactions: Temporary redness, itching, or swelling at the injection site. 
• Rare systemic reactions: Severe allergic reactions like anaphylaxis, though uncommon, can occur and require immediate medical attention. 

Who Should Avoid an Intradermal Allergy Test? 

The test may not be suitable for: 

• Patients with a history of severe anaphylaxis. 
• Individuals on medications that may interfere with test results, such as antihistamines or corticosteroids. 
• Pregnant women. 

How is it Different from a Skin Prick Test? 

• Skin Prick Test: Involves placing allergen extracts on the skin and lightly pricking the surface. It is primarily used for common allergens. 
• Intradermal Test: Involves injecting the allergen under the skin and is more sensitive, making it suitable for detecting specific allergens like drugs and insect venom. 

Preparing for the Test 

• Stop antihistamines: Avoid taking antihistamines or other medications that could suppress allergic reactions for at least seven days before the test. 
• Inform your doctor: Share details about all current medications, recent allergic reactions, and any medical conditions. 

Duration of the Test 

The entire procedure, including observation and result interpretation, takes approximately 45 minutes. 

Is the Test Painful? 

Patients may experience a mild sting or pinch during the injection, but the discomfort is brief and manageable. 

Can Children Undergo the Test? 

Yes, the intradermal allergy test is safe for children when conducted by trained healthcare professionals. 

What Happens if the Test is Positive? 

If the test result is positive: 

• Your doctor will confirm sensitization to the allergen. 
• You will receive recommendations for managing your allergy, which may include:  
• Avoidance strategies: Practical tips to reduce exposure to the allergen. 
• Medications: Prescriptions for antihistamines, epinephrine injectors, or other medications. 
• Desensitization protocols: Options such as allergen immunotherapy (allergy shots). 

Alternatives to the Intradermal Test 

• Skin Prick Test: Often used as the initial step for diagnosing common allergies. 
• Blood Tests: These measure allergen-specific IgE levels and are useful when skin tests are not feasible. 

Accuracy of the Intradermal Test 

The intradermal test is highly sensitive and provides valuable insights into specific allergies. However, false positives can occur, so the results should always be interpreted alongside your clinical history and other diagnostic tests. 

Post-Test Care 

• Monitor the test site: Keep an eye on the injection site for delayed reactions. 
• Report systemic symptoms: Contact your healthcare provider if you experience symptoms like difficulty breathing or widespread rash. 
• Follow medical advice: Adhere to the allergist’s recommendations regarding allergen avoidance, medications, or further testing. 

Book Your Allergy Test at Allergy Central 

At Allergy Central, we offer safe, accurate intradermal allergy testing performed by experienced professionals. With instant reporting and personalized care, you can trust us to help you manage your allergies effectively. 

• Location: Bangalore, India 
• Website: allergycentral.in 
• Phone: +91-9035275945 

Take control of your health today. Schedule your intradermal allergy test and start living a healthier, allergy-free life!