Icelandic mare with itchy, scabby tail dock

My 7 year-old Icelandic mare has been constantly rubbing her tail for weeks in the Alabama winter. She has been dewormed and her udders are clean. She is domestic-born and has never had any skin problems before, and this is not summer eczema/sweet itch. I tried MTG (though it's possible I didn't properly get it to all affected skin (the entire tail dock, ESPECIALLY at the bottom), as it's no easy feat to adequately get all of the skin at the hair roots. Since I felt like the MTG wasn't working, I washed her tail and for the past 1.5 weeks I have been applying iodine/providing solution mixed about half and half with baby oil, at least once oer day. It seems to be working as the scabs are definitely healing and the several hairless spots along the dock look clean and good. I haven't been washing it out, because it is winter. The baby oil is meant to keep the skin from drying out (as I guess betadine does?) because if it is dry, it will be itchy and she will continue to rub. I am kind of concerned that the iodine stuff might be drying out her tail? Like I said, the issue seems to be clearing up...but she is definitely right back to rubbing her tail when I arrive in the late afternoon to apply more stuff. The whole thing is making me nuts because I am terrified she will destroy her tail, and also because Internet searches (per usual) are full of "omg don't use _____ because it will destroy the tail and your horse will explode in disaster etc." (insert any product's name into the blank, as there is sure to be a similar cautionary warning about it somewhere!)
So....does anyone have any ideas/input?? :(

Are you 100% positive you got any and all pinworms? You have to break the cycle and deworm 3 weeks apart once they get to the rubbing stage.


What does the rest of her coat look like? Dandruffy? Scurf? Is it soft and look shiney? Even winter coats should be shiney and soft under the dirt.

What is she eating?

Also, some mares can get a bean/smegma in their personal parts right at the bottom just inside the point where they pee. There is a pocket there. Its not common but does happen.

I am not 100% positive about the pinworms. She was last dewormed with safeguard. I know pinworms are itchy, but would they cause all the scabby, flakey skin up and down the tail dock? Under the dirty top layer, her coat is really soft and skin looks good. However, I did forget to mention that she was also rubbing her mane, about four or five inches down from the poll. The skin was also flaky there with a couple of scabby areas. I applied the same iodine/baby oil mixture and the area seems fine now....

Fenbendazole isnt the best dewormer anymore unless its for a debilitated horse etc that you are working up to a dose of good dewormer for. It has alot of resistance up to 90% unless you power pack (double dose it by weight for 5 days in a row) Also, you need to weight tape the horse and be SURE you deworm for the proper weight. Under dosing is common a a big problem.

Ivermectin would be the product I would use first, and then in 3 weeks Id use Quest or Quest Plus if I hadnt already dewormed for tapeworms after the frost and be sure my horse was cleaned out. You can get a fecal but not everything shows on one. Since your horse is tail ribbing, IMO its best to methodically eleiminate possibilities and clean the horse out first. THEN get a fecal to make sure you at least got the things that will show in a test. JMO for your case here.

Scabby tails can certainly be caused simply from constant tail rubbing due to parasites yes. That can also cause a bacterial infection since the skin is compromised. It can also be caused by fungal issues, dirty personal parts, the mane being involves also at one time makes me think it could also be a dietary deficiency like Vit A which is super common this time of year to be deficient in. Its the primary cause of rain rot.

The best way to deal with this is systematically eliminate possible causes. The first and easiest is by deworming her properly with products that absolutely kill and be sure to break the cycle by deworming again after 3 weeks. I had this problem once a long time ago before I knew that some dewormers were ineffective. It took a couple deworming s to get it under control and some topicals to help control the residual dry skin and healing itch.

Try this
Shapley's Original M-T-G - First Aid Supplies from SmartPak Equine

Dont use MTG until you test it on a small spot first. Some horses are VERY allergic to sulphur.

I personally hate it. It stinks like burnt bacon and its greasy and lingers untill you bathe..and even then it takes several scrubs and still stinks in thick winter hair. Bleh.

She might have pinworms. In a book I have it says to wash the anal area daily with soap and water and to use disposable paper towels to keep from giving it to other horses.