The Important Difference Between Clinical Allergy and Allergy Sensitization

A doctor's review of patients' medical history is as important as skin test results in diagnosing clinical allergies.

A doctor’s review of patients’ medical history is as important as skin test results in diagnosing clinical allergies.

I’m sure you have patients come into your office and say: “I was once tested by an allergist and told I was allergic to everything green!” I’m  always dismayed when I hear that patients were given results in this manner. Almost no one is allergic to “everything green.” Patients may be sensitized to multiple allergens but most likely they’re not allergic to them all. Making the distinction between clinical allergy and allergy sensitization requires the doctor to study each patient’s health history in conjunction with allergy test results.

Let’s demonstrate with a food allergy example… A patient visited my office and told me that he attended a party and ate a piece of cake. Within 15 minutes, he developed hives (urticarial) all over his body. He wasn’t sure what was in the cake but was worried about what he should avoid in the future. I tested him and the results showed a positive for tree nuts — walnuts, cashews and pistachios. The skin tests also showed positive for milk and eggs, but he told me that he eats eggs and drinks milk all the time without a problem. We found out that the cake contained walnuts, so I diagnosed him with walnut and tree nut allergy. I explained that his positive allergy tests to egg and milk demonstrated that he has allergic sensitization to the raw pure proteins in those foods, but, with no clinical complaints, he can still continue to eat them.

Here is another example of a potentially confusing situation that you may encounter using the AllerVision skin testing panels: you test a patient and find she is allergic to several tree pollens, grass pollens and ragweed pollen. The patient’s history says she only has symptoms in the spring — from March until June. She has no symptoms in the fall. My assessment would be that she has clinical allergy to the spring pollens, trees and grasses, and allergic sensitization to ragweed. This distinction becomes important not just in educating the patient, but in determining the patient’s course of immunotherapy. In this case, you might decide to treat the patient for the trees and grasses but leave the weeds out of the equation.

The allergy world is buzzing with research on diagnostic techniques to delineate clinical allergies more clearly. One company is working on a blood test that involves Resolve Component Testing. That measures a protein called Ara h2 — highly specific for peanut allergy. Preliminary studies indicate 95% accuracy. In the meantime, don’t forget the importance of clinical history in conducting the “detective work” required to distinguish clinical allergy from allergy sensitization. And remember that, as always, the AllerVision clinical team is available to work with you and discuss your cases any time you have questions.

Dr. Dean Mitchell

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The Late Summer Breezes Send Ragweed Pollen Flying

Western Ragweed

Ragweed spreads widespread misery in late Summer.

We’re approaching summer’s finish line and we all want to soak up as much sun and fun as possible before the weather turns chilly. Unfortunately, in addition to marking the end of summer, August hails the beginning of the ragweed pollen season. Ragweed allergy, classically known as Hay Fever, is recognized by allergy suffers far and wide as the “summer cold” that lasts through Labor Day — and sometimes beyond.

I have vivid memories of my father suffering from Hay Fever. I was 10 years old and hopeful that my dad would play catch with me when he got home from work. But one look at his red nose and watery eyes and I knew I’d have to wait for another day… or another season. My father would head straight to his bedroom where he would turn on the air-conditioner and close the door. When my dad stayed outside for an extended period, he had to “pop” Spantial, an ornate combination of sedating antihistamine and decongestant. That helped the symptoms but he struggled to stay awake with the old-fashioned antihistamine, and fought agitation from the decongestant. We’ve come a long way since my childhood in the 70s.

Today, state-of the-art symptom control treatment is available to provide relief for ragweed allergy sufferers but a well-planned approach to treatment is necessary. That means starting a program several weeks before ragweed season peaks. For appropriate candidates, I recommend Nasalcrom spray twice daily starting in early August. This allows time to build up the necessary protection. Nasalcrom is composed of cromolyn sodium, a mast cell inhibitor, and it is extremely safe with virtually no side effects. However, early prophylactic use is the key to success since it takes several weeks to reach effective levels. This is in contrast to steroid nasal sprays which work immediately but, if used for long periods, can have adverse effects.

The new exciting breakthrough in treating Hay Fever is sublingual immunotherapy. The FDA has recently approved Ragwitek, the  pharmaceutical-grade sublingual tablet to treat ragweed allergy. The medical studies have shown the efficacy of this product and validated the benefit of sublingual immunotherapy. My concern is that this product is only available as a high dose tablet without the build-up recommended for desensitizing patients to allergens. 50% of patients had adverse reactions to Ragwitek — such as sublingual irritation from the tablet, itchy throat, sneezing and nasal congestion. Also, Ragwitek is approved only for adults 18 years and older. Since the tablet treats only ragweed allergy, it’s usefulness does not extend to patients with allergy to other weeds or to allergens in the other antigen categories.

Based on my clinical experience, I believe that a better option is the use of sublingual immunotherapy drops, also known as allergy drops. These liquid drops are made from the same allergen extracts used for injections. They can be used to treat multiple allergens at the same time, so they are not limited to ragweed, they are easy to use at home, and they actually taste good. The AllerVision program promotes the safe buildup of allergen doses to achieve tolerance to the allergen for safe, successful treatment. The AllerVision program uses FDA-approved allergens in an off-label method, which is a common practice in medicine.

I’m sure many of your patients have their final summer vacation days planned. Make sure that your ragweed sensitive patients are protected so they can create summer memories that DON’T revolve around allergic disease!

Dr. Dean Mitchell

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