What should you know about percut allergy skin tests?

A clinician usually places labelled drops on the forearm or back, then gently pricks through each drop. A control sample helps show how your skin reacts without the suspected allergen. After a short observation period, raised, itchy areas may suggest sensitisation to a substance.

A positive skin response does not by itself prove that exposure causes your symptoms. Results are interpreted alongside your history, such as symptoms after a food, pet, dust mite, or seasonal exposure. A negative result also needs clinical interpretation.

Tell the testing team about medicines, recent severe reactions, skin conditions, pregnancy, and asthma control. Some antihistamines and other medicines can affect results, so ask exactly what to pause and when; do not stop prescribed treatment without instructions. Wear clothing that leaves the test area accessible.

Avoid scratching the test area and follow the clinic's aftercare advice. Bring a symptom and exposure history so the result can guide avoidance, treatment, or further testing rather than creating unnecessary restrictions.

Tell staff immediately if you feel unwell during observation. After leaving, seek urgent help for breathing difficulty, throat or tongue swelling, widespread hives, dizziness, fainting, or rapidly worsening symptoms. These can indicate anaphylaxis and need emergency treatment.

Ask which allergens will be tested, which medicines affect the test, how long to observe the skin, what a positive result means for your symptoms, and whether a blood test or specialist review is needed.