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Ivermectin reaction/allergy?

CavyConnoisseur

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Hi I've just noticed my girl Delilah has a large round bald patch on the back of her neck with a small amount of flaking and scabs. However she and my other 5 piggies were given a full course of ivermectin a week ago? (There were no issues besides a little dry skin so I gave them a course as prevention.)

They were treated with Pharmaq ivermectin spot on, 1 drop on the back of the neck per 500g once per week for 3 weeks, as it says to do. It's the same stuff my vet prescribes.

She has had this medicine before with no issues and none of the others have it either. Weirdly this bald patch is exactly where the ivermectin was administered so I'm wondering if she had a reaction to it?

Super weird, just want to know what you all think and what I should do? She didn't have this before treatment.
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PigglePuggle

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I would ask the vet, you wouldnt get a reaction against ivermectin itself of course, but the solvents it is dissolved in can cause skin irritation and minor hairloss, this should be mentioned on the patient info leaflet as fairly common side effects.
Howver you havent told us why the ivermectin was prescribed, the lesions you show could be mange mites or could be ringworm which has been mistaken for mange mites at an earlier stage so has got worse because the incorrect medication was prescribed.
I would see the vet who prescribed the spot on for a hands-on examination and also ask for skin scrape tests doing for both mange mites and ringworm so you are sure you are treating the correct condition...
 

CavyConnoisseur

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Hi!

Have you self-diagnosed or has your vet seen this?
My vet checked a different piggie and recommended I give a course of ivermectin to all my pigs in case of mites because she had dry skin. They've had dry skin for almost a year so I dont think they had mites but the vet said to do it anyway. This hair loss is new and none of my pigs have ever had it.
 

CavyConnoisseur

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I would ask the vet, you wouldnt get a reaction against ivermectin itself of course, but the solvents it is dissolved in can cause skin irritation and minor hairloss, this should be mentioned on the patient info leaflet as fairly common side effects.
Howver you havent told us why the ivermectin was prescribed, the lesions you show could be mange mites or could be ringworm which has been mistaken for mange mites at an earlier stage so has got worse because the incorrect medication was prescribed.
I would see the vet who prescribed the spot on for a hands-on examination and also ask for skin scrape tests doing for both mange mites and ringworm so you are sure you are treating the correct condition...
This hair loss is brand new and only appeared after treatment on the 3rd week. It was never there before. Another pig had dry skin so the vet prescribed ivermectin as a prevention. The dry skin has been there for nearly a year so I doubt it was an infection or it wouldve progressed by now, it was given on a just in case basis.
 

PigglePuggle

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Mites or ringworm should really be confirmed with proper diagnostic tests, so if the vet didnt do these before, it is probably time that all piggies and all bald patches were scraped and swabbed and the samples sent off to a lab for a proper diagnosis!
Skin problems and infections often dont occur in isolation, if a piggy is unwell and has a low immune response, just like humans they can become susceptible to many things they may have fought off wasily in perfect health- both mites and ringworm can fall into this category...
 

Wiebke

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My vet checked a different piggie and recommended I give a course of ivermectin to all my pigs in case of mites because she had dry skin. They've had dry skin for almost a year so I dont think they had mites but the vet said to do it anyway. This hair loss is new and none of my pigs have ever had it.
Hi!

Like @PigglePuggle has mentioned, the onset of mange mites and a fungal skin infection (ringworm is the most contagious and aggressive of them) can look very similar. Ivermectin will suppress the fungal to some extent but cannot clear it; it will start up again as soon as the ivermectin has worn off.

I have had two sows with similar patches in a very similar area three weeks apart. One turned out to actually have a mange mites reservoir in the skin there and the other developed ringworm (which I had been dealing with some month earlier).
 

CavyConnoisseur

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Do you guys think she had a dormant infection for the past year with the light dandruff and then treating her now made it worse? Regardless I am going back to the vet, I'm just curious as to what happened here as I've never seen it before. I don't understand how she went from just a little dandruff to this after the 3rd weekly dose, the first 2 doses she was fine🤔 I dont know if mites and fungal can lay dormant for so long?
 

CavyConnoisseur

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Mites or ringworm should really be confirmed with proper diagnostic tests, so if the vet didnt do these before, it is probably time that all piggies and all bald patches were scraped and swabbed and the samples sent off to a lab for a proper diagnosis!
Skin problems and infections often dont occur in isolation, if a piggy is unwell and has a low immune response, just like humans they can become susceptible to many things they may have fought off wasily in perfect health- both mites and ringworm can fall into this category...
None of them had hair loss or scabs previously, just a few flakes of dandruff, the vet said to treat with ivermectin just in case anyway. Its only since the 3rd application that Delilah got this bald patch which is why I'm confused. I'm not sure I was making sense explaining the situation sorry lol! I am going to get it checked and tested, I appreciate your help😊 I don't know if allergic reactions like this are possible or if she had a dormant infection this whole year that was made worse by treatment, do you know if mites or fungal infections can lay dormant for that long?
 

Wiebke

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None of them had hair loss or scabs previously, just a few flakes of dandruff, the vet said to treat with ivermectin just in case anyway. Its only since the 3rd application that Delilah got this bald patch which is why I'm confused. I'm not sure I was making sense explaining the situation sorry lol! I am going to get it checked and tested, I appreciate your help😊 I don't know if allergic reactions like this are possible or if she had a dormant infection this whole year that was made worse by treatment, do you know if mites or fungal infections can lay dormant for that long?
Some guinea pigs can have deposits of eggs in the skin (which cannot be reached and killed off by ivermection) but will break out in the same spot whenever the immune system is lowered for some reason.

It takes just one fungal spore reaching the skin to start an acute outbreak 10-14 days later. Coincidences happen.

Please forget allergic reaction; the skin is not looking sore like it would if that was the case.
 
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