Antibiotic allergies

[yellowsun]

Some musings as I have a suspected tooth abscess and need to try and get an emergency appointment in the morning…

When I was a child, I reacted with a rash/sickness to penicillin. A couple of years ago I had an awful rash to Clyndamycin.

I have heard lots about childhood penicillin allergies not being present in adulthood. I was wondering if I am still allergic or whether my recent reaction makes it more likely.

Has anyone found they are no longer allergic?

No. I was diagnosed allergy in childhood.was accidentally prescribed penicillin antibiotics as a adult. Was instantly vomiting and unwell. There are alternatives.

It's unlikely you'd outgrow a penicillin allergy. It can be dangerous as it is well know for causing anaphylaxis, so best not to risk it.
Clindamycin is not in the penicillin class of antibiotics so the rash you got from that was unrelated to your penicillin allergy. You may be allergic to clindamycin (though it is pretty rare) but skin problems are also one of the side effects of it.
I am quite allergic to penicillins and cephalosporins (which are structurally related to penicillins) but can handle the tetracyclines, macrolides, lincosamides, flouroquinolones, nitroimidazoles and sulfonamides.
There are a lot of choices available, so you shouldn't need to re-try antibiotics you've reacted to.

Actually it is thought that a lot of people do outgrow penicillin allergies. Plus about 9 out of 10 people who are recorded as allergic to penicillin do not have a true allergy.

Being allergic to both penicillin and clindamycin is rare and I would expect would lead to getting specific advice for you from a microbiologist.

For a number of reasons many people labelled as being allergic to penicillin aren’t. Occasionally allergies do improve rather than get worse. Clinda and penicillins don’t cross react.

Which anti-b is best for you now is a conversation you need to have with the potential prescriber - the exact history of the reaction and the pros/cons of the alternatives now will help them make the best decision with you.

@Greybeardy could you explain in a bit more detail please? I had reactions to penicillin as a child/teen so have always said that I was allergic - but perhaps I'm not?!

I'm allergic to penicillin, and "intolerant" of clindamycin, erythromycin and clarithromycin (all gave me horrid gastric upsets/vomiting and rashes) so I'm stuck taking doxycline for nearly everything. When I saw my GP last earlier in the year, they did express the need for a medication review and apparently they are trying people on penicillin to see if the allergy noted in childhood is as bad as thought.... not sure I'm keen, my Mum said I was dreadfully ill and had to observed in hospital for 48 hours.

@owlcat24 the most common reasons people think they are allergic when they aren't:

The reaction was never an allergy eg they had d and v which is a side effect not an allergy

They had a rash but it wasn't due to penicillin allergy

It was an allergy but this has now worn off - can even happen with the most serious types of allergy to penicillin

Finally you may be allergic but not have a serious allergy so you may still be able to have penicillin if the benefit is going to outweigh the risk to you.

Apparently 9 out of 10 people tested find they aren't allergic - it is worth finding out as unfortunately there aren't always alternatives, or the alternatives aren't quite as good.

I have been allergic to penicillin since the age of 5, so I've never tried to take it since. Nowadays, it's on my digital medical record. The last time I was prescribed antibiotics, I was given erythromycin & I've never had an issue. Hope this helps.

@owlcat24 ….what @AnnaMagnani said! It does take a bit of delving into the details to decide whether a childhood ‘allergy’ really was one or not. Sometimes the balance of risk and benefit is in favour of giving the penicillin…sometimes it isn’t. It’s a conversation that needs to happen in real life with an HCP though and not something that people can give specific advice about on MN. HTH.

I think boils down to updating medical knowledge.

We used to think:
penicillin allergy is common
penicillin allergy commonly develops in children
once you have it, you have it forever
even just getting a rash is dangerous
you will probably be allergic to some other antibiotics (cephalosporins) as well so best not even try

Now we think:
penicillin allergy is rare
a lot of those rashes in children were due to viruses and not the penicillin - and a lot less antibiotics are prescribed for coughs and colds than were in the past as well
once you have it, it might well wear off
it's important to know what sort of allergy you have, there could be circumstances where you could put up with a rash to save your life
you probably aren't allergic to cephalosporins as well - it does happen but a lot less than was thought in the past

I have allergic rash reactions - classic hives - to amoxicillin and one other antibiotic. I think possibly flucloxacillin? I have been told by doctors that this means I am allergic to penicillin. I have also been told by doctors that this doesn't mean I am allergic to penicillin!

As there are so many alternative treatments available, I can't see myself ever finding out the truth.

I have had various allergies in my lifetime. I grew out of all my childhood allergies, had a long period with only one allergy, then began developing new ones in my 30s. I was told by the immunologist that it is not unusual to outgrow childhood allergies, but you never outgrow allergies developed as an adult.

Stay away from what you were allergic too, I still am allergic now.

There's a massive difference between itchy hives or swellings (allergic reaction) and a spotty or blotchy rash (side effect), but unless a person has had both, and understood that the second is not what an allergic reaction looks like, they may not recognise the difference.

Though this is my personal experience. For all I know it may be possible to get a non-itchy allergic reaction.

My mother always told me I had a penicillin allergy so avoided it for years. I have an allergy to two other antibiotics so asked my GP if she could refer me to be tested for the penicillin one as I was running out of options, I get a lot of infections for reasons not worth going into. It seems I grew out of my allergy. It’s worth doing just so you know.

I had swollen lips and tongue from an antibiotic for a uti....cannot remember which right now

& then rash on my hands and feet for nitrofuratin (sp?) So I was told I was allergic to both

If I'm not that's great as I get loads of uti s and they are a bugger to cure

As a child I was given penicillin for tonsillitis I think. I got a slight rash and the doctor said I might be allergic to penicillin or that the rash was just linked to the tonsillitis. I hadn't had a reaction before so I suspect I'm not allergic at all, but have avoided taking it ever since. Would love to know for sure.

My daughter outgrew her penicillin allergy we only found out though because she was in hospital and needed iv antibiotics and the best one for treatment contained penicillin. They asked if they could try while she was staying in hospital as they could monitor her closely and she was absolutely fine

Can anyone recommend any allergy testing for penicillin? (I do have reason to ask rather than it just being ‘for laughs’).

The two people i know with true penicillin allergy are allergy to blue cheeses as well. In fact one had anaphylaxis from a cheese sandwich on a plane

I had penicillin as a child and was fine. I recently had it (in amoxicillin) as an adult and got a bad rash. The GP put me down as allergic.

I'm not sure if I am allergic, and would be interested in how you can get tested.

I know that research has been done and many people aren't in fact allergic.

It’s very interesting. I would say my reaction to Clindamycin was probably ‘intolerance’ as it was a rash rather than hives - it was still recorded as an allergy by my GP.