Allergies are common but everyone who thinks they have them do not actually have them! So how do you know if you truly have allergies or not?
First, we need to remember what an allergy is. Most physicians discuss allergies as it relates to the symptoms caused when a substance triggers a reaction that causes our bodies to release an IgE protein. The classic allergic reaction releases histamine, a chemical that causes the symptoms we have come to associate with allergies.
Every time you have a stuffy or a runny nose, it does not mean that you have allergies. And when you say that you have “seasonal allergies”, please remember that there are indeed 4 different seasons. Should I assume you mean the classic spring and fall seasons? What about people with those frequent “summer colds”? Many of those people actually do have allergies!
How do you know if you have allergies?
Just like every other medical problem, there are many ways to diagnose allergies. Most physicians start with the most simple ways and then move to advanced methods if symptoms are not controlled.
Think about evaluating allergies like your physician would evaluate a cough. The most important tool that physicians use to make any diagnosis is the history.
Initial cough treatments may be made just based on the history of the problem that patients report. Over time a simple x-ray may be needed, or a fancier x-ray like a CAT scan could be ordered for that cough. Eventually, a specialist may be needed to perform a procedure to look deeper into the lungs.
This simplified process of evaluating a cough applies to allergies. The evaluation of allergies usually includes some of the following steps:
- Getting a good medical history of the problem
- Ordering blood tests
- Performing skin prick tests
- Recommending skin tests using needles that inject under the skin
So how do physicians decide what to do?
The history of medical problems is ALWAYS important
Many of my patients’ parents report vague things like: “It sometimes happens.” Just NO!
The meaning of “sometimes” is different for everyone. Is that once a week? Once a month? A few times a year?
By the time you feel that a problem is bad enough to seek medical attention, please take a moment to reflect on what you are going to tell the physician. So, what kinds of questions should you be ready to answer?
- How long has the problem been happening? Not just when it got worse leading to this appointment, but when symptoms first started. Many people had symptoms in the past, but none for years. The fact that problems happened before is important.
- What did you do to treat it at home? Many people go to their doctor without any home treatments. This can mean that the problem was too bad to treat at home. Is that what you mean to say? No Tylenol for fever? No cold medications? Why not? I believe there are 3 levels of care, and what you do at home matters.
- How is the problem impacting your life? If your child cannot go to school or has poor sleep, the problem is more severe. If trips to physicians are needed to get antibiotics, the problem may be more severe.
- Other important information:
- Do symptoms come and go all year or just during a certain time?
- Occur outside, inside or both?
- Do any foods or pets make the symptoms worse?
- Have you ever had asthma or eczema?
- Is there a family history of allergies, asthma or eczema? It does not matter the degree, just are they present.
Allergy blood tests
Once a complete history has been obtained, allergy testing may be needed. Allergy blood testing seems to be preferred by parents since it is less “invasive” than skin testing AND because there is a shorter period of “unhappiness”.
However, this test often reveals different results than the skin test. Skin tests are more sensitive than blood tests when it comes to determining if you have allergies. I typically recommend the blood allergy testing method for one of the following reasons:
- The patient is an infant and I am looking to “screen” for mild to moderate allergies
- A medication that blocks skin test results cannot be stopped
- There is a severe skin condition or hypersensitive skin that makes interpreting skin tests harder
- A severe reaction to an allergen has happened in the past, especially foods or animals. Further exposure is avoided.
- Parents do not want the recommended skin testing
Depending upon the allergens that are being tested, the lab will determine how much blood is needed. The blood sample is evaluated and checked for the antibodies of specific allergens that show if you have allergies.
Results of allergy blood tests can take a few days to a week. If a very large amount of antibodies are found, there is a greater chance that a more severe allergy is present. Your physician should go over the test with you and show you how the degree of allergy varies between each substance tested.
Please understand that NO ALLERGY TEST is 100% correct. Some tests identify antibodies, but no significant allergy reactions are associated with it. Some test results show a smaller number of antibodies, but important symptoms are associated with that allergen. This is why the medical history and discussion with a seasoned physician treating allergies is important.
Allergy skin prick test
This type of testing is the gold standard for allergy testing. It is not very invasive, but for young children, it can be scary and feel more invasive because it takes longer than the time to draw a blood sample.
The test is done on the arms or the back using a plastic device that pokes the surface of the skin with tiny amounts of allergens. After waiting about 15-20 minutes, the test results are noted.
If a reaction is present, an area of swelling occurs. Sometimes an excessive amount of redness is present around the swollen area, but the area of swelling is the main way to determine the degree of allergy. The amount of swelling is recorded to compare different allergen reactions.
Combining the results of the allergy test and medical history, your physician will then discuss a specific treatment plan with you. This can include avoidance of the allergen, nasal saline washes, a variety of medications and even allergy shots for long-term control.
Allergy testing using needles
The dreaded word: needles! The good news is that many people, especially young children, do not need the needle testing option. However, this test can give information that the other two testing methods do not.
Using a very tiny needle, a small amount of an allergen is injected just under the skin surface. Once again, there is a need to wait 15-20 minutes to allow for the allergen to react with antibodies that the body has already made. The area of swelling shows that an allergic reaction has happened.
So why would we use this testing method? I usually recommend the needle injection testing option for children over age 12 who have had a long history that is consistent with allergies, but the skin prick test did not show significant results.
I have found that chronic allergy suffers sometimes do not show positive test results until the allergen is injected deeper under the skin. This test can give incredibly useful information and should be performed if your physician recommends it.
This type of testing is also useful to assess insect or medication allergies but should never be used for food allergies.
Miscellaneous allergy testing
There are other ways physicians can determine if you have allergies. I personally do not use either of these but for completeness, I will briefly mention them.
- Patch testing: This type of testing is useful when an allergy is suspected from direct skin contact. The allergen is taped to the skin for up to 48 hours and then a reaction is noted in 72-96 hours.
- Food Challenge: If significant food allergies are suspected but do not to show up on blood or skin testing, your physician may recommend this test.
There are several tests physicians can order to diagnose allergies. However, please remember that getting a great medical history is important. Physicians can often quickly move through possible causes and decide which tests or treatments are needed because we have seen this many times.
This is the reason you need to always ask for the credentials of your healthcare provider! Everyone with similar symptoms does not have the same problem. You should be ready to provide a good medical history just as your healthcare provider needs to have the appropriate training and experience to use the information that you have reported.
If you suspect that you (or your child) have allergies, I highly recommend that you discuss this with your physician. Testing can be used to make a proper diagnose and help map out the best treatment options. I highly recommend reading a post by pediatrician Dr. Kristen Stuppy who does a fantastic job discussing many different ways to manage allergies.
I will continue to add more posts about allergies and discuss allergy shots vs allergy drops, both which alter the immune system to reduce allergy symptoms. So be sure to consider subscribing to my blog to avoid missing a post!
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