The following Allergy test and procedures may be done at the first allergy visit.
Spirometry is breathing test. It usually involves blowing into a machine for 6-10 seconds at least 3 times. It measures airway obstruction and sometimes response to treatment with a bronchodilator (such as albuterol). Children as young as 5 years may have a spirometry test. Spirometry is very important in making an initial diagnosis of asthma, determining its severity, and allowing us to determine which medications may be needed to help with asthma symptoms.
Allergy Skin Tests
Skin prick tests can be placed on the arm or back, depending on patient preference and the age and size of the child. A very small amount of an allergen is put into the skin by making a small “prick” on the surface of the skin. The prick tests are done with a sterile, disposable plastic prick test device that looks like a small tooth pick. The sensation is generally not painful and only mildly uncomfortable.
A prick is done for each individual allergen. For example, skin testing for environmental allergies may involve 20 “pricks” for a child and more for an adult. The appropriate number of tests will be determined after meeting with the allergist.
If you or your child has an allergy, a little swelling that looks and feels like a mosquito bite will appear at the prick site. These reactions occur within about 15 minutes. Generally you won't have any other symptoms other than a small hive where the test was done.
If your prick skin tests are negative but your physician still suspects you might have allergies, more sensitive “intradermal” tests may be used in which a small amount of allergen is injected under the skin (these are not done for food allergy).
Skin tests are usually more sensitive for screening for most types of allergies compared to blood tests.
Certain medications may prevent skin tests from reacting. Please see the list of medications that should be avoided before skin testing.
Sometimes your allergist will order a blood test to look for allergy antibodies (IgE or immunoglobulin E) to food, environmental, or venom allergens (such as pollen, mold, animal danders, or house dust mites). These can be used to confirm the likelihood of reaction to food and also be used to follow the progress of the food allergy over time.
The IgE bloods tests are usually done when skin tests cannot be done, such as for patients taking certain medications, for certain skin conditions that may interfere with skin testing, for uncooperative patients, or in rare situations, when skin testing may not be safe. For most food allergies, IgE blood tests are often done in conjunction with skin testing and at follow up visits to determine if the food allergy may be going away.
For food and medication allergy, you or your child may be scheduled for a challenge. Small, increasing amounts of a food or medication are taken by mouth every 15 or 20 minutes over a 2-3 hour period followed by observation for at least an hour. It is very important that they be supervised by a physician with specialized training and experience, such as an allergist.