What Are Allergy Diagnostic Procedures and Treatments?
Diagnostic tests for allergy may include any or all the following:
Skin Tests
Skin testing is a common and reliable test to determine your child’s allergies. It takes about 15 to 20 minutes. Small amounts of liquid that contain different allergens (food, environmental trigger, or injectable medicine), are applied on the surface of the skin (forearm or upper back) with a small scratch. If a positive reaction appears, it will itch like a mosquito bite with a bump and redness. After 15 minutes, the provider will measure the red bumps with a clear ruler and the itch will slowly go away over the next 30–45 minutes. A reaction to the skin test does not always mean your child is allergic to the allergen. Your child’s doctor will determine this. However, a non-reactive skin test is a reliable sign that your child is NOT allergic to that substance.
Blood Tests
Blood tests for allergies measure the antibody that causes allergic reactions, called IgE antibody, to specific allergens in the blood. The blood test most commonly used is called ImmunoCAP. Blood tests may be used when skin tests cannot be performed, or in addition to skin tests to give further information about the allergies. As with skin testing, it is important to remember that a positive blood test does not always mean your child is allergic to that allergen.
Graded Oral Food Challenge
This is a test to find out whether a person is allergic to a specific food and is performed in the Allergy Clinic or in an inpatient hospital setting. Medicines are available to treat a reaction if it occurs, and the provider and nursing staff monitor the patient carefully. The challenge starts with a small amount of the suspected allergic food and is increased over time until your child can eat a full serving or show symptoms of an allergic reaction. Food challenges are done if it is unclear whether a patient is allergic to the food in question, or to see if a previous food allergy is resolved. A Food Challenge visit typically lasts about four hours.
Oral Immunotherapy
Oral immunotherapy (OIT) is a process of building up tolerance to a food your child is allergic to. The goal of OIT is to decrease your child’s sensitivity to the allergic food. By slowly introducing the allergic food it may lower the risk of life-threatening allergic reactions if the child is accidently exposed. The process is also known as desensitization.
The first step in this process is to find a safe starting amount of the allergic food for your child. This visit is called an Initial Escalation. During this clinic visit, the doctor will identify the right dose your child can tolerate without having allergy symptoms. Your child will then take this small amount of the food every day at home.The dose slowly increases at clinic visits every two to four weeks until a set serving amount is reached.These visits are called Up Dose Visits.
Your child is a good candidate for OIT if:
- We can find a safe starting dose of the food allergen for your child.
- Your child can cooperate with eating the food every day.
- You are willing to make sure your child gets their dose of the food allergen every day.
- You can come for clinic visits every two to four weeks for roughly six months or longer, depending on how the process goes with your child.
Drug Allergy Testing
For patients suspected of having an allergy to injectable medicine, allergy skin testing is occasionally helpful to see whether they are allergic to the medicine. In many cases, an oral dose of the medicine is given to see whether the patient is allergic to it. This is done in the Allergy Clinic or in the hospital, depending on the nature of the previous reaction and the general health of the patient. The medication challenge can be a single dose or gradual dosing depending on the medication and the child’s history of reaction. The doctor and nurse watch the patient carefully, and medicines are available to reverse any reaction that occurs.
Pulmonary Function Testing
This test measures how well the lungs are working. Pulmonary function testing is often done for children with asthma to monitor how well their asthma is controlled. It is also done to diagnose asthma or other respiratory problems. Children around 6 years old or older are generally able to perform pulmonary function testing.
