Skin Prick Test(SPT) helps to check allergic reactions
to various kinds of allergens like - Fungi, Mites, Pollen, Dusts, Epithelia,
Insects, and Food.
Details
Description
A Skin
Prick Test is a diagnostic procedure done to identify the allergy-causing
agents (called allergens) that trigger various kinds of allergic diseases. Also
known as a scratch test, we test a
variety of important allergens that are found in the local region including
pollen of trees, grasses and weeds, spores of moulds, dust mites, insects, and
animal dander, as well as common food allergens. Depending on a patient's
history, specific individualized allergens can also be arranged.
Skin Prick
is a Non-invasive Test and is not painful. This type of testing uses needles (lancets)
that barely penetrate the skin's surface. There is no bleeding and only mild to
moderate discomfort is felt at the site of the prick.
In this
test, a small quantity of allergen is placed on a specific point on the forearm
or back. The outer layer of the skin is scratched to let the allergen seep in
and symptoms of allergic reaction are observed. If any redness or inflammation
appears on the skin, then that person is having allergy.
A Skin
Prick Test usually takes about 20 to 30 minutes.
A positive
skin test is when a visible allergic reaction develops corresponding to a
specific allergen. Bigger wheals usually indicate a greater degree of
sensitivity.
A negative
skin test means that you probably aren't allergic to a particular allergen.
Test
Preparation
Before any
allergy testing, the health care provider will need some information about:
Details of
the past allergic reactions experienced
Family
history of specific allergies
Past
illnesses
Work and
home environment
Lifestyle
and habits
Food
and eating habits
Precaution
Certain
medicines like antihistamines can interfere with the skin test and must be discontinued
at least 10 days to 2 weeks before the test, after consulting with the doctor.
Certain
medications may also increase the risk of an allergic reaction during the test.
Also, the
patient should always come accompanied with at least one person for this test.
Risks
involved
Since a
very tiny amount of the allergen is used, the reaction is also very small and
fades away within a few hours.
The
reaction can at the most manifest as a few itchy bumps.
Patients
with Asthma tend to develop some severe allergic reaction or an asthmatic
attack within the next 24 hours. Therefore, they must always keep the doctor
informed about their condition and always carry their inhalers and medication
while going for this test.
Skin Prick
Tests are usually not done on pregnant women, people on certain medications, or
those with very bad eczema.