What is this test?
Skin prick testing (SPT) is a standardised method to identify sensitisation to specific environmental allergens. It is performed on the forearm using standardised allergen extracts.
Why is it done?
Skin prick testing is useful for: identifying relevant allergens in allergic rhinitis, asthma and other allergic conditions, guiding allergen avoidance advice, and selecting patients suitable for allergen immunotherapy.
Who may benefit?
- Patients with allergic rhinitis
- Allergic asthma or suspected allergic triggers
- Recurrent seasonal respiratory symptoms
- Suspected environmental allergies
- Patients being considered for allergen immunotherapy
How is it performed?
Small drops of allergen extracts are placed on the forearm. A small lancet creates a tiny prick through each drop. After 15-20 minutes, the skin reactions (wheals) are measured. A raised wheal indicates sensitisation.
Patient Preparation
Stop antihistamines for 5-7 days before the test as advised by your doctor. Do not apply creams or lotions to the forearm. Inform the team of all current medications.
What information does it provide?
A wheal of 3mm or more than the negative control indicates sensitisation to that allergen. Results must always be interpreted together with clinical history. Sensitisation does not always mean clinical allergy.
