I started a thread on here several weeks ago thinking my old Arab had Sweet Itch but it turned out to be a reaction to Neck Threadworm larvae migrating out of his body, mostly via his midline but he also had outbreaks around his eyes, on his upper neck and under his tail.
Check out the articles on Neck Threadworms on a website called www.thehorsesback.com
. There are three or four articles that describe the problem and how to treat it. My poor old guy had a horribly swollen sheath and was lying down and rubbing his belly RAW from the fiery itching. The solution is not rubbing cream on the horse...it's killing the larvae with Ivermectin.
I urge everyone who thinks their horse has Sweet Itch to read the articles. In my horse's case, I spent a fortune on creams before I discovered the articles and double-dosed him with Ivermectin. His case was so bad that I did a second double-dose about a week and a half after the first. Now he will need to get a normal dose of Ivermectin every month all through fly season.
And my veterinarian also recommended generic Zyrtec - one tablet per 100 lbs. of body weight - TWICE a day through the end of fly season. That brought the swelling in the horse's sheath down in a couple of days.
This problem is very common in elderly, neglected and rescue horses. They suffer horribly. I have only owned this horse for about a year and a half and I mistakenly believed he'd been on a regular worming program previously.
I have a feeling that Sweet Itch may also be worm related - not neck threadworms, perhaps, but some other parasite because it looks identical to the damage caused by Neck Threadworms - the only difference is in the location.
My horse is growing hair in all the locations that were previously raw and oozing. I rest my case.
Oh, and AFTER the larvae have exited through the horse's skin, scrape all the scabs off and THEN you can apply a soothing cream such as DurVet or Udder Balm to calm the skin down. But putting cream on it before killing the larvae is a waste of time and money. Do NOT apply anything that has an ingredient that can DRY the skin. Just makes the suffering worse.