There are many ways to test to see if your symptoms may be caused by allergies. At the ENT and Allergy Center, we will help you find the right method for you.
Our center offers five main types of allergy testing to help your doctor identify what might be causing your allergy symptoms. These include:
- Skin prick testing
- Intradermal testing
- Patch testing
- Blood testing
- Oral Food challenges
- Medication testing
Types of allergy testing
Skin prick testing
Skin prick testing is the most common test because of its high rate of reliability, minimal discomfort and ease of use. The test takes about 45 minutes.
Skin prick testing involves gently pressing a small plastic device dipped into different allergens onto the skin of your forearms or back. These allergens remain on the skin for 20 minutes, and then the results are read. Some patients find this test slightly uncomfortable. If you or your child prefer, your provider can prescribe a numbing cream for you to pick up and apply to your or your child’s arms or back 1 hour prior to the test.
A positive result, or wheal, looks swollen like a mosquito bite. This swelling tells us that you are allergic to that allergen. Positive reactions usually disappear on their own within a couple hours. If needed, you can apply hydrocortisone cream to the area afterward.
If you are asthmatic or your provider has concerns for asthma, the nurse may have you perform a quick breathing assessment prior to applying your test.
Intradermal testing
Intradermal testing is performed on the upper arms or back by placing a small amount of allergens just under the skin with a small needle. This forms a small wheal that we then let sit under the skin for 10 minutes. Once the 10 minutes has lapsed, we then read the results and an official copy of the result is provided to the patient.
If you are asthmatic or your provider has concerns for asthma, the nurse may have you perform a quick breathing assessment prior to applying your test.
Patch testing
Patch testing is used to determine possible allergens that cause a reaction on the skin. This kind of allergic reaction usually causes redness and itching. This involves placing panels or patches of substances to which you may be allergic on the upper back. We may use other areas depending on how many patches are applied, if skin is not suitable, etc. Patches require two separate days of appointments. The first day usually occurs on a Thursday and is when your patches will be placed. Your second day will be scheduled for the following Monday or Tuesday and will be the appointment in which your test is read, and you receive your results. You cannot have one appointment without the other. Additionally, depending on the number of patches ordered and the amount of area to which patches are applied, additional testing appointments may be necessary in order to complete the testing.
Among these substances are common allergens like:
- Fragrance
- Nickel
- Preservatives
- Rubber
- Wool
Preparing for patch testing
It’s important to keep your skin in good condition prior to patch testing as it helps ensure accurate results. There are a few ways in which you can prepare your skin:
- Avoid sun exposure for one week before your appointment.
- Avoid topical medicines such as creams and ointments where the patches will be placed.
- You may use moisturizers on your skin until the day before patch testing.
- Antihistamine use before and during the test is permitted.
- No steroid use (oral or topical)
During patch testing
The patches remain on your back for 48 to 72 hours. It’s important that you do not apply anything to the patches, keep the patches dry, avoid itching or rubbing the patches, and avoid physical activities that might loosen the patches. Schedule during a time that you are able to avoid sweating and getting wet (avoid times of sporting events, planned vacations, exercise, etc.) It’s also helpful to avoid direct sunlight to the patch area, and reducing hot areas and activities that might interfere with the patches. It is OK to take prescribed medications as usual, excluding steroids.
After the 48 to 72 hours, the patches will be removed at home. Someone will help you peel them off and relabel. However, if you do not have anyone at home to help you, let your nurse know so that they can apply your patches to an area you can reach so you can remove them yourself.
During this time period, do not shower or take a bath. Our dermatologists recommend washing areas of the body with a washcloth where the patches are not located. It is important to continue following these instructions after removing the patches. You must continue following instructions until after you have seen your provider for the final reading.
Reading results
Not every allergen will react positive, so you might be allergic to a percentage of the allergens we test. It’s also possible you will be asked to come back again in a few days to read any results that might not have reacted in this short timeframe.
Once allergens are identified, our team will work with you to create a personalized treatment plan. You might be seen by both a dermatologist and an allergist at our ENT and Allergy Center of Missouri. We’ll also make sure our team updates your primary care doctor. Thanks to being part of an academic health system, that’s just one way we’re able to provide you with the best care possible.
Penicillin allergy testing
The ENT and Allergy Center can provide skin testing and oral challenges for patients with a penicillin allergy. Many patients spend long periods of time labeled as allergic to penicillin, and this can complicate the treatment of bacterial infections, increase surgical costs and potentially promote antibiotic resistance. Correctly identifying those who are not allergic to penicillin and removing the stigma of penicillin allergy has many benefits for the patient.
If you would like to undergo evaluation for penicillin allergy testing, the first step is to schedule a consultation with one of our allergy providers. This will help determine if you are an appropriate candidate to undergo skin and oral challenge testing.
The skin testing portion starts with a prick test that consists of pricking the skin with two controls and 2 forms of penicillin. It requires keeping your arm still for 20 minutes after it is applied. If the prick test is negative, we then move forward with an intradermal test. The intradermal test consists of placing a small amount of the same controls and penicillin under the skin with a needle; it also sits for 20 minutes and then the results are read. If both skin tests are negative, a two-hour oral challenge is given in which you will take one penicillin pill and one amoxicillin pill while your vital signs are monitored. In total, this test can last about four hours in which you will remain inside of the building and will be unable to eat or drink except for water. Before you leave our office, we will ensure if you can safely take penicillin and amoxicillin. Both you and your doctor will be given a copy of the test results at the end of your appointment.”
Oral challenges
In instances where skin prick and blood tests do not provide a definitive diagnosis, your allergist might suggest an oral challenge. This is a highly accurate diagnostic test for food allergy.
Risks of allergy testing
Though extremely rare, the most serious reaction that can occur with skin testing is anaphylaxis. This is a major allergic reaction that can include:
- Chest tightness
- Hives
- Lip swelling
- Throat swelling
- Wheezing
- Or a more extreme reaction
Allergy testing cannot be done if any of the following apply:
- You are taking an antihistamine, beta-blocker, tri-cyclic antidepressant, natural medicine or other medications that can affect the test results. See the complete list for additional information.
- Your spirometry test is low.
- You have asthma and your asthma has been worse lately or is not in good control.
- You have chest pain or unstable angina or have had a recent heart attack.
- You have a cold or upper respiratory infection, and/or a temperature over 99.6.
- Your skin is overly reactive and may give false positive results.
- You are pregnant or breastfeeding.
- You are wheezing or short of breath.
If allergy skin testing is not appropriate for you, blood testing may be an option.