• Kaelyn Turner

But, did you die? Part 1.

Hi. My little dog Pepper pooped in my car this morning while I was driving her and her sister to their haircuts. Thanks to that and various other happenings, it’s been a while! Overall I’ve been #TiredAndUninspired. And, per usual, this is already riveting right out the gate.


She's so damn cute, we can barely get her in trouble. She knows exactly how to drop her ears and make her eyes real big. There she is between running sprints in my vegetable garden and nearly ruining it but whatever.

Topics for this blog pretty much come from things I see a lot or have to repeat explaining 18,287 times every week at work. I work in an Urgent Care Clinic, so infections and antibiotics are a star in the show. Anecdotally, I’d say the 3 most common infections we see are E. Coli Urinary Tract Infection, Group A Strept Throat, and Staph skin infection called Cellulitis (or Abscess). Wait, and how could I forget Gonorrhea?!

Side note: STDs are still a THING. All of them. Really alive and well. Thriving, if you will? You do whatever you need to do with that information, I’ll spare more detail.


This blog will have 2 parts sort of. The original idea for this blog was to discuss Penicillin allergy. So so so many people report a penicillin allergy from childhood, and what many people may not know is that there are 2 main types of penicillin allergies. The other part of this blog will be about “culture and sensitivity”.


“Certain drugs kill certain bugs” is the way I tell it to patients.

What usually prompts me to say that, is that a patient comes in, with say, a tooth infection/dental infection, and they tell me they took some antibiotics they "had left over". There are multiple issues with that statement, but I’ll leave it at that for now...

Let’s begin, shall we?


Everybody has heard of Penicillin, right? It’s the OG - the Original Gangster - of antibiotics.

In Urgent Care land, we still use straight up Penicillin for dental infections, dental abscesses, and Syphilis. But what we use even more are Amoxicillin and Amoxicillin-Clavulante a.k.a. Augmentin a.k.a. the delicious pink bubble gum medicine you have to keep in the fridge. These two are used for ear infections, strep, some UTIs, mild pneumonias in certain types of patients, sinus infections, and some skin infections! Super handy. Usually tolerated very well in terms of stomach upset or diarrhea compared to others. So, what’s the problem?


Amoxicillin is a semi-synthetic spin-off of Penicillin. Amoxicillin acts on the same cell receptors that Penicillin does .... soooo if you have an allergy to one... you can have an allergy to the other. If you report penicillin but not the other two as allergies, it doesn’t matter, we still consider you "allergic" to all 3. And as I’m sure the audience is well aware, we live in a “Sue-Happy” society. Lawsuits are filed in a blink of a fake eyelash in these times, and none of us want to get sued. We also don’t want people to call and complain about us and try to get us fired, which is exponentially more common! Fun, right? And most importantly, we don’t want anything bad to happen to you! Despite what the internet says, more than most of us are in it to "do no harm."

The research says that 10% of all patients report a penicillin allergy. Ehhhhh idk. Seems a little low to me.


Iiiiiiii would also guess that 90% of people who report a penicillin allergy say 1 of 2 things:

it gave them a rash/hives when they were little OR they don’t know why they are allergic to it, “my mom just always told me to say I am.” So, if you find yourself with a fresh case Syphilis or a middle ear infection, you’re in a bind with the former, and just a touch more complicated to treat with the latter.

y’all. I’m geeked out. SWEAR my guess that 90% of people have mild reactions..... was just a guess LOL *hair flip* “Approximately 10% of patients report an allergy to penicillin, however up to 90% of those patients do not have a true allergy. The incidence of anaphylaxis to penicillin is 0.02%-0.04% and is mediated by a Type 1 hypersensitivity reaction.” (1)

Sooooo, the two main/common types of allergic reactions to Penicillin are called:

Anaphylactic = Type 1 = Serious = You're swelling all over like a blowfish and you can’t breathe and you need an EpiPen and an ambulance - STAT.

and

Cutaneous = Type 4 = Not Serious = Skin rash.


When it comes down to it, if you need a pure Penicillin or a Penicillin-derived antibiotic, and you know for sure you just had a mild rash or itching, we will likely give you the medication and keep you for monitoring for up to an hour after your first dose. If you have Syphilis - that's a you-need-it situation, not a you-want-it antibiotic situation. My husband the pharmacist also told me this fun story once: A patient had a true, anaphylactic penicillin allergy, and contracted Syphilis (BTW: a sexually transmitted bacterial infection that has to be treated with 3 doses of a large amount of Penicillin injected into your butt muscles, yes, 3 times, each 1 week apart). (2) So, this person was admitted to a whole ICU for administration of the drug, to treat the Syphilis, and monitor for anaphylaxis so that if/when it occurred, they could rapidly reverse it.

True story. Cool. #condoms but that's none of my business.


Wow okay, back to the point.


"All penicillins share the same core beta-lactam and thiazolidine ring structures but differ in their side chains. Identification of true penicillin allergy is critical as 80% to 90% of people once considered allergic are ultimately able to tolerate penicillins... Serious allergic reactions to penicillin are Type 1 and mediated by IgE. Risk factors for IgE mediated reactions include high-dose parenteral administration and repetitive or frequent dosing of penicillins." (1)

You don't have to understand or be able to pronounce beta-lactam and thiazolidine ring structures. Think of these 2 rings as your base floor plan with the neighborhood developer. Every house built in that neighborhood has the same core floor plan, but some people will add extra driveway to accommodate multiple vehicles, or some people will add more concrete and overhang for a back patio. Others will add a loft over the garage or a fourth bedroom in the back of the house. The same core floor plan is common in all the houses in the neighborhood, same layout and number of bedrooms, bathrooms, but they can add things on to each house as needed for each unique family. Their function is all the same: a home, shelter, living space. Their "extras" make them work for the differences between different families.


K. So the original penicillin has a "core beta-lactam ring", which is just the name of it's chemical/molecular (as in molecule) structure, and a thiazolidine ring. That's just "how it's made." The other drugs, chemical structures pictured above, some of which you may have heard of, seen, or taken before, are just the core PCN molecule, with "extras". Didja notice Amoxicillin up there? Bet you did, smarty pants.


"Cross-Reactivity – A Definition

Cross-reactivity occurs where the proteins in one food or substance share characteristics with proteins in another food or substance. A person who is allergic to one may therefore have

positive allergy tests to other foods with similar proteins." (4) But also, a person who is

allergic to one food or substance, may not be allergic to a "related" food or substance, which often leads to unnecessary avoidance of certain foods, products or medications.


I really said "food or substance" a lot of times.


"A similar but less common reaction can also occur in people who are allergic to natural rubber latex because some of the proteins present in natural rubber latex also exist in a similar form in certain fruits such as bananas, avocado and chestnuts." (4)


Interesting. Bananas....and LATEX....cross-reactivity possible. LOL y'all are bad. Sorry to my grandmother who will read this. Couldn't pass it up.


So like.... the point is... if you've ever worn a latex glove, a latex condom, or been exposed to medical equipment/supplies that are made with latex.... and you are allergic to those things.... think about it..... have you ever eaten a banana or anything that contains banana, and been fine? I bet most of you that have a latex allergy have been fine.


Making sense? K.


Another class of drug that has a similar chemical structure to the penicillins are the "Cephalosporins." Examples of cephalosporins that you may be familiar with: Cefdinir, Cephalexin (Keflex), Ceftriaxone (Rocephin), etc etc etc..... that are also "Beta-Lactam" antibiotics. So, what do you now know? If you are allergic to Penicillins, you can also be allergic to an entire other class of drugs, because of their similar chemical structures. What are the odds? Small, but present. Cephalexin and Cefdinir are really commonly prescribed for kids with ear/nose/throat infections. I'll let you know, though, that every single time I prescribe a Cephalosporin to a child (or anyone) that has any penicillin listed as an allergy, the computer system gives me a "you shouldn't prescribe this to cover your ass legally" warning. 9/10x I click past it and prescribe it anyway - as do most people. There are multiple "generations" of Cephalosporin drugs. Just like there have been multiple generations/models of Ford Mustangs, Chevy Camaros, Jeep Chrokees. The old ones are are still available for purchase, but there are also new ones.


"...the overall cross-reactivity rate is approximately 1% when using first-generation cephalosporins or cephalosporins with similar R1 side chains."


So, why do I click past the CYA warning box?


"It’s rare to be allergic to both penicillin and cephalosporins. But if you’ve had a serious anaphylactic reaction to penicillin antibiotics in the past, you shouldn’t take cephalosporins.

It’s uncommon to have an allergy to both penicillin antibiotics and cephalosporins, so cephalosporins can be used cautiously in people with a penicillin allergy.

However, people who’ve had a serious anaphylactic reaction to penicillin antibiotics shouldn’t take cephalosporins.

In addition, some cephalosporins are more likely to cause a reaction in people with a penicillin allergy. These include:

  • cephalothin

  • cephalexin

  • cefadroxil

  • cefazolin" (7)

There's definitely a risk involved with choosing to do that. But picking an antibiotic for you isn't as easy as we make it look. We are thinking about all this ALL the time, guys. But this is why we rely on "evidence-based practice" or EBP. This is why I copy-paste the bottom lines from the research in these blogs. These are the things we read in order to inform our decision making. So, when will I NOT click past the warning box, and not give you a Penicillin or a Cephalosporin...... when you KNOW for sure you had an anaphylactic reaction and you describe it to me when I ask you - or if you have no idea what happened but use terms like "it was really bad" or "they took me to the hospital" or "I don't remember if I had to go to the hospital but my mom told me I was severely allergic." That's good enough for me (and most other healthcare providers) to know that you are a Penicillin Unicorn and we have to treat you special.

Plot twist:

"The incidence [how often it happens] of anaphylaxis to penicillin is 0.02% to 0.04% and is mediated by a type 1 hypersensitivity reaction ... IgE antibodies decrease over time. In patients who have previously tested positive for penicillin allergy, there is an expected 10% decrease/year of a subsequent positive reaction. Therefore, with the avoidance of PCN, 80% to 100% of patients will ultimately test negative for penicillin allergy 10 years after the initial positive test." (or presumably, their first allergic reaction.) (1)


Sooooo... If you're now in your 20s, 30s, 40s+ and you have avoided penicillins your whole life because you had hives or a rash when you were 2 and you had amoxicillin for the first ear infection of your life.... You might want to consider finding out if you're actually "allergic" to penicillin!


Okay, how do I find out?


Allergy testing! (6)


AAAAI: American Academy of Allergy, Asthma, and Immunology. Say that 3x fast.

"As clinicians dedicated to the advancement of the knowledge and practice of allergy, asthma and immunology for optimal patient care, the AAAAI recommends patients who believe they have a penicillin allergy or who have documentation in their health record regarding a penicillin allergy should undergo skin prick testing to verify if they are truly allergic to penicillin, before an alternative non-penicillin antibiotic is prescribed. As many as nine of 10 patients who are tested actually do not have an allergy to penicillin." (5)



If you are going to have an anaphylactic, immune-system-attack-reaction to a penicillin you took, it's going to happen within 30 minutes to 3 hours of taking that dose. So, if you're going to try this, and want to see if you can take Penicillins off your allergy list, here's what has to happen:


  1. You need a primary care provider. Do not come to me at the Urgent Care and ask for a referral to an allergist or else I'll feature you on my snapchat urgent care bingo series called "Things We Don't Fix at Urgent Care." :)

  2. You need a referral from that PCP to an Allergist or a physician (like a pediatrician) that is board-certified in Allergy, Asthma and Immunology.

  3. You make an appointment with the Allergist.

  4. You stop taking any and all allergy meds 1-2 weeks before your test, including any nasal sprays and other steroids.

  5. You go to your appointment. You let them prick you with a teeny amount of penicillin antigen.

  6. You wait in the office. They check on you and watch you. They have epinephrine and IV fluids and benadryl and stuff all ready to go in case you go South.

  7. In most cases - You get a result in an hour! And then you know! Then the allergist will tell you - yes, you can safely take Penicillin off your allergy list - OR - nope, mayday. No PCN for you. Click the link for source number (6) to read more!

Underuse of penicillins and overuse of other classes of drugs for basic, common infections contributes to what I believe will be the end of the world. LOL. Ever since I saw that Will Smith movie (I think I've talked about this before in another blog but idk) where they all get that virus and they turn into the white alien looking things with fangs and the world ends but Will survives - ever since I saw that, I think that's how the world will end. With drug resistant organisms killing us all. I mean unless humans kill each other first, which is looking more possible every week these days. Ugh. Humans. I would love it if you would click here to read the section on "Bacterial Resistance". (9) Scroll about half way down and the section is titled in bold. I don't buy meat that's been treated with antibiotics. Or eggs. I spend more money and go to certain stores for meat and eggs. You don't have to care or do that, but I do. It's just a thing I care about lol Anywho.........


Hope you learned something today AND hope you enjoyed this!!



Yum. A cup o' pills. #8amMedPass #IYKYK



(1) ncbi.nlm.nih.gov/books/NBK459320

(2) cdc std treatment guidelines

(3) Chemical Structure of Penicillin Antibiotics

(4) https://www.anaphylaxis.org.uk/knowledgebase/cross-reactivity/

(5) https://www.aaaai.org/About/Advocacy/More-Advocacy-Campaigns/Penicillin-Allergy-Testing#:~:text=As%20clinicians%20dedicated%20to%20the,should%20undergo%20skin%20prick%20testing

(6) https://www.mayoclinic.org/diseases-conditions/penicillin-allergy/diagnosis-treatment/drc-20376226#:~:text=With%20a%20skin%20test%2C%20the,high%20likelihood%20of%20penicillin%20allergy.

(7) https://www.healthline.com/health/cephalosporins#allergic-reactions

(8) https://pubmed.ncbi.nlm.nih.gov/21742459/


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