You’re Probably Not Allergic To Penicillin After All

You’re Probably Not Allergic To Penicillin After All

I went through most of my life thinking I was allergic to penicillin. I’d had hives with a dose of the stuff as a child, and an also-allergic family member taught me to look for an allergy section on every medical form I filled out, and make sure to write “penicillin” on the line.

But the reason I’m telling you this story is that it turns out I’m not allergic to it after all. About 10 per cent of us have a penicillin allergy on our charts, but less than 1 per cent of us have a legit allergy to go with it. And if you can take that fake allergy off your chart, you’ll likely have an easier and cheaper time in all your future dealings with the medical system.

A true allergy that should stay on your chart is the kind that involves IgE antibodies. But most of us who got a rash after taking penicillin actually had a different reaction, one that involves IgG antibodies, and which isn’t likely to happen if we take the medication again.

So when I saw an allergist about something else, and mentioned my possible penicillin allergy, she ordered a skin test for penicillin. A nurse injected a small amount of penicillin under my skin, and even after waiting 15 minutes or so, my skin hadn’t reacted at all. That means I got to take home an envelope with a couple of penicillin pills for what’s called an oral challenge. On the first day I cut one of the pills and put some of the resulting dust on my tongue. The next day I had a third of the pill, the next day two thirds, and later today I’ll have a full pill. So far I’ve had no reaction at all, which means I’ll likely be able to get the allergy off my chart.

Why You Should Know If You’re Really Allergic

Penicillin is the first choice for treating many infections, so if you can’t have penicillin, you’ll often end up with something less effective or with more side effects. Many common antibiotics are broad-spectrum, meaning they kill many different types of bacteria, but that’s usually not what you want. Most of the time, it’s better to take penicillin because it can kill off the bug that’s bothering you without disrupting as many of your body’s good bacteria.

Alternative antibiotics can also be expensive. One recent study found that if you can’t have penicillin in the US, you’re likely to pay more for prescriptions, and a hefty amount for hospital stays. Thankfully in Australia these costs are much less and your doctor can easily prescribe you the best alternative for your situation.

Your total costs include both the price of the drug and any medical care dealing with side effects or other necessary treatments.

Getting tested is probably worthwhile in the long run, given the increased lifetime costs, but whether to get the test done is up to you. Consult your General Practitioner if it’s right for you.


  • American article not edited for Australian viewers again.

    Also this could be quite dangerous advice and really should be prefaced with a ‘consult your Doctor’

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