Category Archives: Allergy

Oral Testing of Reported Penicillin Allergies?

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Penicillin is miraculous.  It was discovered in 1928 by Alexander Fleming (founding the modern era of antibiotic medicine) and is still the most common antibiotic prescribed in my jails.  The dentist and I use Penicillin VK as our preferred initial agent for dental infections.  I prescribe PCN VK, as well, for strep throats.  I use amoxicillin occasionally for sinus infections and UTIs and even amoxicillin/clavulanate (Augmentin) occasionally. 

Because penicillin is so useful (and inexpensive), I hate to hear the words “I’m allergic to penicillin.” If a patient with a dental infection can’t take penicillin, for example, the dentist commonly prescribes clindamycin, which is expensive, a pain to administer three times a day and has potentially bad side effects.  I have seen more than one patient who developed C. difficile after getting a broad-spectrum antibiotic because of a reported penicillin allergy–probably unnecessarily!

This problem is pretty common since about 10% of the adult population will report a penicillin allergy.  However, research has shown that, when tested, more than 90-95% of patients who state that they have a penicillin allergy really do not. These patients can be harmed by giving them an inferior antibiotic more likely to cause them harm than plain old penicillin.

The test most commonly used to gauge true allergic status is Penicillin Skin Testing (PST). No jail or prison that I know of does skin prick tests.  We also don’t refer patients reporting penicillin allergy to an allergist for testing.  We just groan and prescribe an inferior antibiotic. 

However, this could potentially change based on research published this year on the safety and efficacy of “Direct Challenge” penicillin allergy testing.  Direct challenge means giving a low-risk (this is important) patient an oral dose of whatever penicillin you want to prescribe and observing them for an hour for an allergic reaction. This has been done in studies and has been reported to be safe and effective.

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Sample Food Allergy Guideline

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Today’s post is the second in a series of sample clinical guidelines.  All of these sample guidelines will be placed under the “Guidelines” tab (above) as they are published. I view these sample guidelines as a group effort!  If you have a suggestion, critique or simply a better way to phrase some concept, say so in comments.

I wrote about food allergies previously on JailMedicine in “Food Allergies: Sorting Out Truth from Fiction” (found here). Since then, I have had more email requests for a Food Allergy guideline than all other sample guidelines put together.  It is clearly a BIG issue in corrections. Continue reading →

Interesting Articles of the Week: Prescriber’s Letter and Medical Letter

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20121128The saying goes that just half of what we were taught in medical school is wrong.   Also half of what we think we know about medicine now is wrong.  The problem is that we don’t know which half!  But this does mean that keeping up-to-date with the current medical literature is very important.  Why just yesterday I read that maybe leeches and purging aren’t such good treatments for headaches after all!

Two of my favorite sources of continuing medical education are the Prescriber’s Letter (found here) and the Medical Letter (found here).  Both provide evaluations of medications and changes in medical thinking that are unbiased by marketing from Big Pharma.  Both are subscriptions services (which they have to be since they don’t accept advertising) but both are well worth the money.

Recent editions of both publications have some really interesting information that I would like to share here.  Because I don’t want to infringe copyrights, I will summarize the information presented instead of “copy and paste.”  Those who are interested can look up the originals!

Prescriber’s Letter, January 2013

Beta Blockers for Hypertension?  Not for most patients!

Beta-blockers are no longer a preferred drug for uncomplicated hypertension.  Even though they do lower blood pressure, beta blockers are less effective in preventing long term bad outcomes like heart attacks and strokes than alternative medications like  diuretics, ACE inhibitors/angiotensin receptor blockers (ARBs) or calcium channel blockers. Atenolol appears to be the worst offender in this regard.  The one population in which beta-blockers should still be used are those patients who have had heart attacks or otherwise have known coronary artery disease.  So if your patient has had an MI, use metoprolol or carvedilol.  If not, use something else for hypertension.  Get rid of atenolol entirely.

The Medical Letter, Dec. 24, 2012

Can you use cephalosporins in patients with penicillin allergies?  Yes, in most patients.

I was taught in medical school that patients with a true penicillin allergy had a 10% risk of also being allergic to a cephalosporin.  It turns out that this is not true.  The true incidence of allergic reactions to cephalosporins in patients who relate a history of penicillin allergy is only 0.1%.

There are two reasons for this.  First of all, if you skin test all people who say that they are allergic to penicillin, only a small minority will be found to be truly allergic (I have heard less than 10%).  Second, even those patients who are proven to be allergic to penicillin by skin testing have only a 2% chance  (not 10%) of also being allergic to cephalosporins.

Chemically, penicillins and cephalosporins do share a common beta-lactam ring, but it is the side chains of the molecules, not the central ring, that cause allergic reactions.

So if a patient has almost died from a penicillin allergic reaction, i.e, Stevens Johnson Syndrome or toxic epidermal necrolysis or the like, I would not risk the 2% chance of repeating the event.  But if the patient gives a history of a vague rash thought to be due to penicillin, the risk of using a cephalosporin is very, very low.

Do you still use beta blockers for uncomplicated hypertension?  Why or why not?  Please comment.

Do you give cephalosporins to patients with a stated penicillin allergy?  We would like to hear your comments!

I have only listed two of my many favorite resources for Continuing Medical Education.  What are yours?  Please comment.

 

 

 

Food Allergies: Sorting out Truth From Fiction

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In my previous incarnation as an emergency physician (before I discovered “The Way” of correctional medicine), I saw a lot of cases of acute allergic reactions. It is a very common emergency complaint; I have probably seen hundreds in my career. But when I began my jail medicine career, I was still unprepared for the sheer volume of food allergies claimed by inmates. Who knew so many inmates had so many food allergies?

Of course, most of them don’t. Most just don’t want to eat something on the jail menu. Inmates believe that if they claim an allergy to a food they dislike, you cannot serve it to them. They will claim allergies to tomatoes, onions, mayo, etc., when really, they just don’t like these foods. Tuna casserole doesn’t seem very popular, for some reason. Continue reading →