Drug Allergies


 

Aspirin Allergy, Asthma and Polyps

15 percent of all asthma patients and 40 percent of asthmatics with nasal polyps are allergic to aspirin and other NSAID's (e.g., Advil, Aleve, Motrin). Often, they need repeated sinus surgeries and oral steroids for asthma. In 1979, researchers showed that desensitizing them to aspirin results in fewer asthma flares, increased sense of smell, and fewer surgeries. For desensitized patients, the need for sinus surgery drops from once every three years to once every ten years.

We also get aspirin allergy referrals from cardiologists. Cardiac stents that could save a patient the risk of open heart surgery recommend that you take aspirin afterwards to keep the stent open. Here's the thanks from one cardiologist: "You just saved this lady cardiac bypass surgery. Not bad for an allergist." Arthritis patients often cope better with pain if they can take NSAID's. When they are allergic to aspirin, it limits their options.

There are two completely distinct ways to be allergic to aspirin. Aspirin triggers asthma and sinus disease in some people, and hives in others. Aspirin desensitization usually takes two days, but then you must continue to take aspirin twice per day to remain desensitized.

In February 2011, a patient drove to Houston from Michigan to get desensitized for his aspirin exacerbated respiratory disease by The Allergy Clinic. He couldn't smell, had already had six sinus surgeries and often needed steroids for asthma. He found us on the Internet and left his email with our nurses. Emailing back, I asked why he would drive right by Chicago and Memphis to go to Houston since those medical centers perform aspirin desensitization. Or why not go to Scripps Clinic in San Diego where they pioneered this 30 years ago. His answer: I can't get those guys to answer all my questions the way you have. He probably meant to say that Houston is a much prettier place to visit than La Jolla.

Note: Information contained in this article should not be considered a substitute for consultation with a board-certified allergist to address individual medical needs.


 

Allergic to Benadryl? Allergic to EpiPen? Allergic to Steroids?

It sounds strange, but some people are allergic to Benadryl. Yes, Benadryl treats allergy, but it gives several people hives. Most of the time, it's just an allergy to the red dye in the product; substituting dye-free Benadryl fixes that problem. However, you can be allergic to the active ingredient, diphenhydramine, usually presenting as hives, but sometimes more severe allergic reactions.

What's the best way to become allergic to diphenhydramine? (Probably not something on your bucket list.) Putting Benadryl cream on itchy skin that is broken or open at all, like in eczema and poison ivy. If you have itchy hives with no abrasions in the skin, Benadryl cream is great. But diphenhydramine can become a contact allergen when it gets to the lower layers in the skin, just like nickel and latex. As a general rule, we would rather our patients use Noxzema moisturizing cream than Benadryl cream for itchy skin.

If you are allergic to Benadryl, you may also be allergic to Dramamine and Tavist, which cross react with Benadryl. We no longer treat reactions with liquid Benadryl; liquid cetirizine (Zyrtec) works just as fast, but it makes fewer people sleepy and it lasts much longer. Dr Hugh Sampson, one of the premier experts in food allergy, published a study in 2011 showing there was no significant difference in how fast liquid cetirizine works vs. how fast liquid diphenhydramine works. But he did make note of the fact that more patients became sleepy on diphenhydramine than on cetirizine. J Allergy Clin Immunol 2011 Nov;128(5):1127-8

Even more unusual is the patient who is allergic to EpiPen. If one is extremely allergic to sulfites, you may have anaphylaxis when injected with an EpiPen. Luckily, epinephrine is also available in small glass vials for single use that have no preservatives. EpiPens can be cumbersome to carry; fortunately, a new epinephrine auto-injector is coming to the USA soon, called EpiCard. It is the height and width of a credit card and the thickness of a small cell phone. EpiPens can be cumbersome to carry; fortunately, a new epinephrine auto-injector, called Auvi-Q, is now available. It is the height and width of a credit card and the thickness of a small cell phone. Go to Auvi-Q website for details.

Another remarkable but interesting problem is allergy to steroids, or cortisone. Most of the time, the allergy is only to one type of steroid, and the patient will do fine with another type of steroid.

Treating an allergy to substances that are supposed to relieve allergies is no problem for us. We have experience treating unusual types of allergy, and we get consultations asking for help from doctors in several specialties, including from other board-certified allergists.

Note: Information contained in this article should not be considered a substitute for consultation with a board-certified allergist to address individual medical needs.


 

Iodine Dye Allergy

At least once a week, we hear a patient tell us that they are scared to eat fish because they had an allergic reaction to iodine. The next part of the story involves the Radiology procedure they underwent when they had the reaction. Let's untangle two myths and shed some light on this:

1) Radiocontrast Media (RCM) that contains organic iodine may cause adverse reactions such as urticaria, angioedema, bronchospasm, laryngospasm and shock. These reactions are not truly allergic in origin. Instead, a non-allergic pathway triggers what looks exactly like an allergic reaction. While we don't know the exact mechanism, it is apparently related to the high osmolality (concentration of particles) of these agents. If you have had this type of reaction and need another procedure done, your physician will probably recommend a lower osmolar preparation to decrease the risk of another reaction.

The risk can be further decreased by pre-medicating with antihistamines (e.g., Allegra, Claritin/Clarinex or Zyrtec) and steroids (e.g., prednisone). I don't recommend Benadryl anymore for outpatient pre-medication protocols. The risk of tolerating the procedure just fine, but then falling asleep and crashing your car into a tree on the way home must also be considered. Why would you fall asleep? Don't forget that most over the counter sleeping pills are made of diphenhydramine (the active ingredient in Benadryl).

2) Seafood may contain iodine. However, seafood allergy is not caused by iodine; rather, to specific proteins in fish and shellfish (e.g., parvalbumin, tropomyosin) that also do not contain iodine. Thus, fish or shellfish allergy does not indicate a sensitivity or allergy to iodine.

So how did the two myths get tangled? Allergic reactions tend to occur in people who already have other allergic reactions. So the person who has allergies (e.g., shrimp) is at higher risk to have another unrelated allergic reaction than the person with no history of allergies.

Many thanks to the American Academy of Allergy, Asthma and Immunology for providing this update. Their website is a terrific source for physicians and health consumers.

Note: Information contained in this article should not be considered a substitute for consultation with a board-certified allergist to address individual medical needs.


 

Penicillin Allergy

You're allergic to penicillin (PCN). What happened, and when did it occur? "I don't remember, it was over 25 years ago, but the doctor told my mom not to ever give me PCN again." So the doctor gives the patient a different antibiotic, probably broad spectrum ("stronger") and more expensive. This is one reason we have more drug-resistant bacteria. The second reason is patients demanding (and doctors prescribing) antibiotics for common colds.


As Dr. Sheldon Kaplan of Baylor College of Medicine pointed out in the April 7, 2011 Houston Chronicle, "Inappropriate and indiscriminate use of antibiotics is a major factor contributing to the problem of antibiotic resistance… Antibiotics cannot treat … respiratory viral infections."

For the third reason, look at Economics 101: drug companies make very little money inventing antibiotics. Someone gets sick, they take the antibiotic for a week or so, and then they're done. Big Pharma would rather invest in the 19th alternative to Lipitor or the 23rd competitor of Prozac. Those medications tend to be taken every day for many years. This adds up to Dr. Kaplan saying, "Infections and medical procedures considered innocuous today will become as dangerous as they were before…" What can be done? Good luck with patients no longer demanding antibiotics, and the Tea Party won't be thrilled to hear about more government spending on antibiotic research.

Yet there is one thing the humble allergist can do. That patient above has a 90 percent chance of no longer being allergic to penicillin. 10 percent of penicillin allergic lose that sensitivity every year, so after 10 years, only a small fraction remain allergic.

That doesn't mean all patients once labeled allergic to penicillin can safely use it, but allergists can perform penicillin skin testing and challenge to confirm if someone is or is not still allergic. For the majority (>90 percent) who test negative, they are at no increased risk to use penicillin. Maybe that will slow down antibiotic resistant bugs.

Note: Information contained in this article should not be considered a substitute for consultation with a board-certified allergist to address individual medical needs.

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