Skin Prick Testing

Skin Prick Testing

Skin prick tests, also called scratch tests, are reliable for diagnosing allergies. Combined with a detailed clinical history and interpreted by a skilled healthcare professional, they provide valuable insights into allergic conditions.

These tests have been widely used in allergy diagnosis for many years, offering a proven as well as effective approach to identifying sensitivities.

Why is Skin Prick Testing Important?

A skin prick test helps identify the allergens responsible for triggering symptoms such as rashes, swelling of the mouth and throat, itchy eyes, nasal congestion, sneezing, and even severe reactions like anaphylaxis.

By pinpointing specific allergens, the test aids in creating a tailored treatment plan, which may include desensitization or immunotherapy for allergens like dust, pollen, or pet dander. This helps you manage your condition effectively.

How Skin Prick Testing Works

Skin prick tests work by introducing a small amount of an allergen into the top layer of your skin, allowing your immune system to respond.

If your immune system identifies the substance as an allergen, it prompts mast cells in the skin to release histamine. This results in a small wheal-and-flare reaction—a raised, red, itchy bump surrounded by redness.

The size of the wheal is measured to assess the likelihood of an allergy. While a reaction indicates sensitivity, a larger wheal increases the probability of an actual allergy to the substance.

What Can a Skin Prick Test Detect?

A skin prick test is a valuable diagnostic tool used to determine sensitivities to various allergens that may trigger allergic conditions such as:

  • Hay fever (allergic rhinitis)
  • House dust mite allergy
  • Pet/animal dander allergy
  • Allergic asthma
  • Eczema (allergic/atopic dermatitis)
  • Food allergies
  • Penicillin allergy
  • Vaccine allergy
  • Drug allergies (e.g., antibiotics, local or general anaesthetics)
  • Latex allergy
  • Insect venom allergy

What Happens During a Skin Prick Testing?

A skin prick test allows for testing multiple allergens simultaneously, depending on your medical history and symptoms. The test is often done on the inner forearm.

Here’s what happens:

  • A droplet of liquid with different allergens is applied to your skin.
  • Using a tiny lancet, the skin beneath each droplet is gently pierced. While this may cause slight discomfort, it is generally not painful.
  • If you are allergic to a particular substance, a small, red, itchy bump will form at the site within 10 to 15 minutes.

Your consultant will document any reactions and provide a detailed report of the findings, helping you better understand your allergies.

How to Prepare

Before undergoing a skin prick test, your consultant allergist will review your medical history and discuss your symptoms, including when they occur.

It is essential to stop using antihistamine medications (such as cetirizine, fexofenadine, loratadine, chlorphenamine or acrivastine) at least 48 hours prior to the test. These drugs can alter the results, leading to inaccurate readings.

What to Expect After Skin Prick Test

Once your skin prick test is complete, your consultant will review and discuss the results with you. Based on your reactions, they may recommend additional tests to gather more information.

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