I remember having some allergic reaction to an anti-biotic as a teen. It made my hands and feet puffy and itch like crazy. The doctor said: “Oh, that’s a classic drug reaction.”
Recently, Squiggy cut his paw when he got stuck in the ceiling and he has just finished a course of anti-biotics.
I was tossing the empty bottle of his meds out, and I got curious: if Squiggy had been allergic to the anti-biotic, how would I have known? Would his paws have gotten itchy too the way my hands and feet did? Or would I only have known when he keeled over half-dead?
The most common allergic sign you would see is facial swelling and hives. If they have an anaphylactic reaction it could skip those and just collapse with pale gums/tongue and possibly have difficulty breathing. Sometimes you may even see vomiting and diarrhea, especially in cats as they usually go the V & D route before you see swelling or hives.
Animals can have allergies to medications but in 27 years as a Vet. Tech. I have only personally seen maybe two or three animals have allergic reactions to penicillin and those always manifested as hives.
Dogs and cats can have allergic reactions to a lot of other things, most commonly insect bites/stings and vaccines. IME the dachshund is the breed most likely to have an allergic reaction to anything.
Adding to this - ferrets can have allergic vaccine reactions as well, to the point where my vet asks us to stay around with the ferret for 20 minutes after vaccination to allow time for symptoms to develop. If they do, they tend to give Benadryl (yes, the same stuff) to knock down the reaction. It’s been a while since I owned a ferret who reacted, but I recall breathing issues and IIRC some drooling.
We had a Morgan stallion that got a serious cut, and after treating that, our Vet gave him a penicillin shot to suppress any infection. The allergic reaction to this was very dramatic. His head drooped, breathing became labored, and within 60 seconds he had dropped to his knees and was nearly unconscious.
The Vet ran to his truck to get an antidote, ran back, and injected that into him. It took 15 -30 minutes until the horse recovered enough to stand up again, and he appeared shaky for about 24 hours or so. Had the Vet not been there to treat him, he would likely have died within a few minutes.
Oddly enough, this stallion had been receiving regular penicillin shots 2-3 times per week for several weeks, when fighting off a serious infection. This had been only a few months before the allergic reaction. Our Vet said this wasn’t unusual – previously non-allergic horses could develop such an allergy after a period of heavy exposure to penicillin. He also said that over time, the allergy would tend to fade away. (Don’t know if that happened – we made sure that this horse never got another penicillin shot for the rest of his life. When you see a strong young stallion sink to his knees and fall over a few seconds after such a shot, you don’t forget it!)
Our Medical director for our ambulance service is a Pigeon freak, you know the homing pigeons?
He vaccinates his own and always has eppi on hand. Well we were going over our BLS med protocols and he tells us about using an expired epi pen when one of the birds reacts. He held it wrong and the injection needle pierced through his thumb:p
We thanked him for the wonderful revelation:D