Skin Prick Allergy Test
What is it?
A skin prick test is a simple and safe method of testing a person whether he or she has immediate allergy (IgE mediated) to a specific allergen. Skin prick testing is more superior that IgE radioallergosorbent (RAST) blood test in that it is more sensitive and provides results instantaneously. It is also relatively cheap. It does not test for delayed onset food allergies or intolerances.
The allergen can be from the food or from the inhalant. It allows clinician to assess whether the child’s symptoms are attributed to allergens.
Why it is needed?
It helps to determine if patients have immediate allergy to specific food groups such as milk, egg, wheat, soya, fish and nuts. A positive test indicates patients have immediate allergy to specific food group. It is indicated in patients who have unexplained bowel symptoms such as nausea, abdominal, constipation and diarrhoea. Respiratory symptoms such as wheeze, difficulty in breathing, sneezing, and rhinitis usually indicate aeroallergen allergies.
Skin prick testing results should always be interpreted in conjunction with detailed allergy focused history. The test involves applying lancet onto the allergen droplets placed on the skin. A wheal diameter of at least 3mm is regarded as a positive reaction in children.
What preparation is needed?
The patient should not take short acting antihistamine for 48 hours and 5 days for long acting antihistamine before the skin prick test. The site for skin prick testing ideally does not have active skin lesion such as urticarial or eczema.
How long does it take?
It takes about 15 minutes for the procedure to complete.
What is the risk?
Anaphlaxis can occur in exceptional rare case. It can cause local irritation on the skin particularly if patients have positive skin prick testing.
Book Appointment
Call 07961 767 854 or complete our enquiry form. We try to respond within 30 minutes between 7.00am and 7.00pm (London time).