Skin Prick Allergy Test in Children by Dr. Srikanta J T

The substances that trigger allergies in children are called allergens. An allergy is an immediate reaction to a substance that is touched or consumed. Children mostly suffer from allergic reactions in the form of a skin rash or a stuffy running nose. The cause may not be obvious, but there are several reasons as to why a child might suffer an allergy. Doctors say that most of the allergies in children are genetic.

Types of Allergies in Children and the Reactions

Different types of allergies can occur due to different reasons. We list some of the common allergies in children and their manifestations.

1. Seasonal Allergies

Seasonal allergies are the allergies that occur due to seasonal or environmental changes. These kinds of allergies are more common in toddlers. Seasonal allergies can cause allergic rhinitis.

Reactions

• Stuffy nose
• Running nose
• Continuous sneezing

2. Food allergies

Food allergies are very common in children. These allergies may occur due to milk, soya, certain kinds of seafood, and nuts like peanuts and walnuts.

Reactions

• Wheezing
• Nausea and vomiting
• Indigestion
• Diarrhoea
• Trouble breathing
• Stomachache
• Hives
• Rashes on skin

[Read : Nuts and Peanuts Allergies In Children]

3. Environmental Allergies

Environmental allergies occur due to pollen, insect bites, and other external factors like certain soaps, shampoos, house hold cleaners and detergents.

Reactions

• Rashes on skin or hives
• Scaly skin or itchy skin
• Wheezing
• Red and itchy eyes

[Read : Insect Bites: First Aid And Home Remedies]

When Should You Consider Getting Your Child Tested For Allergies?

Since the immune system of a child is still in a developing stage, most of the food and seasonal allergies go away as they grow. But not all allergies are the same. Get an appointment with your child’s paediatrician if you see persistent allergic symptoms such as

• Runny nose
• Wheezing and trouble breathing
• Asthma
• Hives on the skin
• Rashes on the skin
• The continuous cold that does not regress

Continuous symptoms can be annoying for your little one. See a doctor if you notice any obvious allergy symptoms. It is also important to know your family history to understand the heredity of the allergies that your family carries. If there is any genetic inheritance of allergies, and you don’t have the allergy, it implies that you are just a carrier of that particular gene.

Once you visit a paediatrician, they may conduct a physical examination before going for any other tests. Doctors may also ask for the clinical history and current medical status of the child and question the parents regarding any hereditary allergies before proceeding for clinical tests.

What Are the Different Types of Tests Available For Allergies?

There are different types of tests available for allergies. Doctors may require examining the kid before prescribing any particular test. Allergy tests for children include skin tests and blood tests.

1. Skin Tests

Again, the skin tests are of three types- skin prick test, patch test and intradermal test.

a) Skin Prick Test

This test is done by placing a small amount of allergen on the surface of your child’s skin. The doctors will scratch that part of the skin with a lancet (a needle-like tool) and leave it to react. The skin prick test may typically need 15-20 mins to show the results.

b) Patch Test

This kind of test is carried out by applying the allergen adhesive on the surface of the skin. The results will be recorded as positive if the doctors observe a small red bump that arises after 48 hours of testing.

c) Intradermal Test

An intradermal test is a kind of skin test in which an allergen is inserted into the top layer of the skin. The result can be seen as a red bump on the surface of the skin if your little one is allergic to that particular allergen.

2. Blood Tests

Blood tests are conducted to check the antibodies reacting to the allergens. These antibodies, also called IgE antibodies, are allergen-specific antibodies that react to certain allergens. Blood tests are preferred over skin tests in children. Skin tests very rarely cause anaphylactic reactions. Skin tests, especially intradermal skin tests, may cause adverse effects if your child is extremely allergic to the allergen.

During blood tests, pathologists will collect the blood sample and induce allergen into it. Blood starts to produce specific antibodies that react to that allergen. If your child’s blood reacts to specific allergens without them showing any external symptoms, it indicates that your child may be sensitized to that particular allergen and is not allergic.

How do You Prepare Your Child For a Skin Prick Test?

If you are getting a skin prick test for the first time, you may want to know how you can prepare your little one and yourself for the process. Here are a few things you must remember.

1. Stop Certain Medications

Certain drugs like antihistamines are used to treat allergic symptoms. Antihistamines are the drugs that are used to reduce allergy symptoms like runny nose, and itchy and red eyes. When the allergen binds to an antibody, it releases histamine which causes the reaction by

• Increasing mucus levels, (runny nose and teary eyes).
• Triggering the nerve endings causing itching and irritation
• Releasing more acid into the stomach.

Doctors routinely prescribe antihistamine medications to treat allergies in your little one, but these medications may interfere with skin test results. It is important to speak to your doctor about your child’s ongoing medication before proceeding with any kind of skin test.

2. Make Your Child Feel Comfortable

Children tend to fear strange places and strange people, especially in settings such as a hospital or a diagnostic center. You can make them feel comfortable by staying with them and reassuring them during the test. Your presence will give them the comfort and warmth they need. Try to reassure them that the procedure will be simple and quick.

3. Set Expectations Before Hand

If your child is a little older and is at an age to understand, you can explain the reasons for the test and how it is done. You can also share videos with them to familiarise them with the process. This may give them a better understanding and they will feel better during the testing process.

4. Get a Toy That Your Child Would Like to Play With

If your child is too young, talking to them about the process may not be feasible. Allergy tests are not painful, but the results may take some time. The tests may also cause irritation or itching at the place of the test. Distracting your kid with their favourite toy or a book during that time is a good option. Do not let them touch the spot and engage them in every possible way you can.

Procedure For a Skin Prick Test in Children

Skin prick test is mostly done on the upper back for children. Doctors may suggest proceeding with the test for two or more allergens. Before starting the test, the doctor or specialist will go through the infant’s medical records and understand the previous medical history. They will also conduct necessary screening for ongoing medical conditions like asthma and other respiratory allergies.

The procedure for skin prick test in children includes the following steps.

• The test will start with the process of disinfection of the test site.
• A water-soluble marker will be used to mark for the number and the type of allergens that need to be tested.
• The technician will then place small drops of allergens one after the other above the marked area.
• A small needle-like tool called a lancet is used to slightly prick the skin.
• For each pricking, a new lancet must be used.
• The technician will wipe off the allergens after pricking.
• After a gap of 15 minutes, the doctor or technician will check the results.

Positive – Reddening around the pricked area along with a small bump which is called a wheal. Formation of wheals indicates that your child is allergic to that particular allergen.
Negative – The skin under the pricked area remains normal and does not react.

Skin prick test never causes bleeding, and it is very much safe for children. Your little one might experience slight irritation and itching around the area. Itching and irritation mostly subside in a few minutes. Red spots at the reacted area will also regress within a short time.

What Devices Are Used For Skin Prick Test in Children?

Skin prick testing is a very mild clinical procedure that should be done under the supervision of experienced doctors. Skin prick testing would need very minimal devices. Lancet and grading scale are the two important tools that are mandatory for skin prick tests. The process requires

• Clean disinfectant wipes. Nurses will use these to disinfect the area where they are going to administer the test.
• Water-soluble marker to mark for allergens.
• Droppers, add small drops of allergens on the respective markings.
• A small needle-like device called a lancet to prick the skin for the allergens to get inside.
• Clean tissue paper to wipe off the sample drops on the skin.
• Grading scales to measure the positively reacted site on the skin.

Advantages of SPT

The advantages of skin prick test are

• Skin prick test is a simple and inexpensive test.
• SPT is painless, unlike blood tests.
• It gives results in a very short time and is efficient.
• This test is more sensitive to IgE allergens when compared to IgE antibody tests.
• It can detect allergies effectively.
• The test is an extremely safe and best way to identify the allergens that are responsible for allergic reactions in children.
• Children can be cooperative during the procedure, unlike blood tests.

Limitations of SPT

Like the advantages, there are certain limitations of Skin Prick Testing.

• It is important to ensure the testing with a good quality reagent.
• An under-quality reagent may result in false results.
• The doctors and the staff must be equipped and must be efficient in handling adverse reactions that can still occur in rare cases.
• SPT can be ineffective in children who are on cold and other antiallergic medications.

Are There Any Side Effects of Skin Prick Test?

Some rare but predicted side effects can occur post the procedure of skin prick testing.

1. Children may experience delayed symptoms like prolonged itching and irritation on the skin.
2. Systemic allergic reactions are one of the side effects which is rare but not so rare post SPT. These reactions are non-localized, and the inflammation can spread to other parts of the body.
3. There were rare observations of anaphylactic reactions in children. Especially for intradermal skin tests, they induce the allergen into the top layer of the skin and leave it to react. Food allergy tests can cause anaphylactic reactions in children.
4. Dizziness and lightheadedness because of the allergens can be side effects. Experienced staff can manage such symptoms in the hospital.
5. If the side effects prolong and if your child starts to feel unwell after leaving the hospital, do not hesitate to consult your child’s paediatrician immediately.

An allergy is an abnormal reaction of the body’s immune system to normal things. Your child may exhibit certain symptoms like skin rashes, skin hives, and other digestive problems for some new foods. It means that their body is trying to deny them food, treating it as foreign. To understand the problem, doctors may prescribe SPT, one of the safest tests for the identification of allergens.

Skin prick test in children is an inexpensive, painless, and effective test to identify the allergens that trouble your little one. It is important to get allergies treated in infancy. Allergies can affect children in several ways in the form of sleep deprivation and poor appetite. Getting an appointment with your doctor for any obvious symptoms can be the best decision for you and your child.

FAQ’s

1. How do I Know if My Child Has Allergies?

Your child starts showing certain symptoms of allergies like

• Skin rash or a hive
• Indigestion
• Itchy or irritated skin
• Small red bumps on the skin
• Diarrhoea
• Trouble breathing or wheezing
• Reddened eyes

Any of the above obvious symptoms should be taken to the notice of the doctor. Symptoms like difficulty in breathing can be life-threatening if ignored.

2. What Are Children Allergic to?

Children can be allergic to

• Milk
• Soya
• Certain nuts like peanuts
• Certain types of seafood

It is important to observe your kid after administering certain foods, especially if you have allergies running in families (hereditary). Any clear symptom should be reported to the doctor.

3. What is a Safe Allergy Test For Children?

There are two types of tests performed for allergies.

• Skin tests
• Blood tests

Skin tests, particularly SPT (Skin Prick Test) are considered as an effective test to be performed on children. These tests are also safe for children.

Read Also: Top 10 Potential Allergenic Foods For Your Baby