What do I need to do for my horse who is losing large amounts of hair all the way to the skin?

My mare is 20 yrs. old but has been pretty healthy up until about 3 weeks ago. That's when I called my local Vet and she had a uninary tract infection. I then started her on penicillin the infection has cleared up but she's really losing alot of hair in clumps.

Hhhmm.. I'm not sure.. just hope you like bald horses..

spring shedding?

of course call a vet.

call the vet back

maybe shes allergic to the medicine youre giving her. call the vet and set up another appointment.

call the vet again, but if the clumps also seem to be attached to a waxy, cruddy substance,which may smell a bit yeasty, she may have rain rot. if she is a pasture horse, who frequently gets wet from the rain/dew, this fungus can flourish, but it doesn't hurt them, and it is easy to treat. go to walmart or somewhere with a garden department, and get a container of Captan wettable tomato fungicide. it used to come in a tall round cardboard can, and it is a greyish looking granular powder. first, give your horse a good deep down scrub bath...suave shampoo is fine, or any horse shampoo, or betadine shampoo/the point is to get her clean in the affected areas. then take a small amount of the powder in your hands, make a paste with it, and work it onto the affected areas. this kills the fungus. I would do it daily for a week..the paste, not the bath, just clean off the affected areas before applying more after the initial day's treatment. make sure you groom her good with clean tools--this is the best way to keep her coat healthy. but if her hair is coming out in dry clumps, and the skin seems dry, chapped, or irritated, it may be something else...maybe even a reaction to the penecillin, so call your vet again, she/he probably won't need to make another visit to tell you what it is.

Did the hair loss occur after the pencillin ? On older mares,sometimes they can have hormonal problems (like staying in heat like mine did) and it can cause hair loss. Did your vet examine the mare or just prescribe the pencillin over the phone? If he saw her, he would of noticed any rain rot or any parasite (like lice or ringworm) so should be able to rule those out. Has anything been changed with your mare? Feed or grain or new horses around her? Stress can make any animal blow its coat. I would call your vet and ask him about it, he can take a skin scraping and do some bloodwork on her to rule out things and he can tell you if he thinks its due to the pencillin. With older horses, its better to get anything abnormal with them checked out!

Hmm, my first thought is the medication or rain scald as the others mentioned. It wouldnt hurt to use some "tea cleanse" (tea tree oil + aloe from the feed store) which you can sponge on and let dry, it will help heal & moisturize and also kill any possible bacteria. Good Luck!