Do you or your children suffer from allergies? If so you are among millions of people who also suffer from allergies. Not every sufferer is allergic to the same thing, however. Some people are allergic to things in the home, like pets, mold or dust mites. This means they may have symptoms all year round. Others are allergic to things outside the home, like grass, pollen and trees. For these people, their allergy symptoms will come and go based on the season. Finally, many people can also be allergic to foods. Food allergies actually account for the majority of allergic reactions.
What causes allergies?
Our bodies all have a very elaborate immune system to help protect us from invaders like viruses and bacteria. We have proteins called immunoglobulins (Ig) which help initiate the attack. Sometimes, our immune system attacks otherwise harmless invaders, like pollen. The immunoglobulin that is responsible for this is the IgE. An elevated IgE to an antigen (the protein on and invader that triggers an immune response)might mean an allergic reaction. IgE lives on mast cells and basophil cells and when it is triggered it causes a release of histamine, along with other chemical mediators. The histamine release then causes allergy symptoms.
As noted above, allergens can be in the home, the environment or in our food. Environmental allergens change from season to season depending on the weather and what is blooming. In the spring, pollen from trees is the typical cause of allergy symptoms. However, according to Dr. David Stukus of Nationwide Children’s Hospital, young children need multiple exposures to the pollen, or allergen, before they can develop an allergic response. Therefore, they won’t typically show allergy symptoms until about 2 or 3 years old. Younger children can develop allergies to indoor allergens, like pets or dust mites, because of more regular exposure.
How do I know what my child is allergic to?
Based on the above description of symptoms and timing, your pediatrician can diagnose allergies and initiate therapy without any testing. If your child fails therapy, testing may be indicated. Allergy testing can actually be done in any age child exhibiting allergy symptoms but is frequently negative in “younger children because they are typically being referred or tested for non-allergic conditions such as frequent upper respiratory infections, nonallergic rhinitis, colic, or chronic gastrointestinal symptoms” says Dr. Stukus.
Dr. Stukus states that allergy testing may also be indicated if official diagnosis is needed, treatment options will change or if the parent or pediatrician isn’t sure what is causing a child’s symptoms. For food allergies, “any child who experiences a classic food allergy reaction such as immediate onset hives, swelling or anaphylaxis after ingestion of a food should be referred not only for testing to establish the proper diagnosis, but also for education and anticipatory guidance.” Dr. Stukus and I both agree that with food allergies, the allergist is the best person to let parents know what ingredients to avoid and what to do if their child ingests an allergen and/or develops symptoms. Allergists “stay on top of all the latest research” so they are a great resource for parents and pediatricians. That’s what they are there for!
How will my child be tested?
There are several ways to test for allergies. From Dr. Stukus:
1. Skin prick testing: This involves placing a drop of allergen on top of the skin, then gently scratching the surface to introduce to the allergy cells. If a bump (wheal) and redness (flare) develops, this indicates that an allergy may be present. Results are seen within 15 minutes. One caveat – any medication containing antihistamines needs to be stopped about 4 or 5 days prior to testing otherwise the test won’t work.
2. Serum IgE levels (formerly RAST, now immunoCAP): This involves sending a blood sample to a laboratory to analyze levels of specific IgE (the allergy antibody) towards any type of allergen. Medications do not interfere with this test result at all. Results are not immediate, typically taking 1-5 days, depending upon the lab.
Unfortunately, these tests are not perfect and are considered screening, not diagnostic. They are best used in conjunction with a good clinical history. Also, the size of the response may be more likely to indicate an actual allergy but can not predict the severity of the patient’s response. This is why large panels of blood or skin tests are not recommended. There are many false positives and may lead to diet or lifestyle changes that aren’t necessary.
3. Oral food challenge: This is considered the gold standard to diagnose food allergies. This occurs in the physician’s office and gradually increasing amounts of food are introduced every 10 minutes for one hour until about 6-10 grams (at least 1-2 servings) are ingested. Patients are then monitored for another 2-3 hours to make sure nothing happens. If no symptoms occur, then a food allergy is not present. If symptoms do occur, they can be treated promptly by the physician and their staff, who are equipped to handle anything. Food challenges are not the first test performed, but can be useful when skin/blood testing is inconclusive or if tests indicate a known food allergy may be resolving.
How should I treat my child’s allergies?
There are 2 options for first line treatments for children with seasonal allergies. The first option is an antihistamine. These are good for kids who are itchy with a lot of sneezing and runny nose. Medications like Zyrtec or Claritin block the histamine response without the sedating effects of older antihistamines like Benadryl. They also last up to 24 hours so only need to be taken once a day. The second option is a nasal steroid like Flonase or Nasonex. These medications are good for nasal congestion but “they need to be used daily and consistently and won’t help much when used as needed or only during symptoms. Ideally, these will be started at least 2 weeks prior to the start of allergy season,” according to Dr. Stukus.
“Lastly, when the combination of medications and avoidance measures are no longer effective, desired, or tolerated, then immunotherapy (allergy shots) may help. Immunotherapy involves taking what someone is allergic to, diluting it, then injecting it back into the body. It requires a series of build up injections over 4-6 months, followed by monthly injections for up to 5 years. Symptoms do not improve immediately but may start to lessen after 6-12 months of therapy. Each injection must be given in a doctor’s office with a 30 minute observation due to rare occurrence of anaphylaxis. For the right child, this can cure their allergies and also prevent the development of new allergies and even asthma.”
If you think your child has allergies or may need to see an allergist, contact your pediatrician.
This article was written by Dr. Jaime Friedman of the Children's Physicians Medical Group (CPMG)