Dear Dr. Gray, my 10 year old quarter horse developed hives about the size of a half dollar to a quarter ALL over his body. He has never had hives before. The other five horses on the farm do not have hives. My vet put him on HistAll antihistamine at that time. They went away in a week and then came back in two weeks. I continued him on HistAll with minimal affect. My vet pulled blood and sent it away to a lab in Arizona. The allergy test came back that he is allergic to 17 things ranging from wool, at the top of the list, to willow trees. We sprayed the field he is kept in for weeds and molds, which were six of the allergies. We changed his hay to fescue because he is allergic to timothy, johnson, and orchard grass. I have taken away all the possible things showing up on his allergy list. However, we cannot keep him safe from the pollens and molds on the allergy list due to the weather and wind. We have had him on flax seed meal, Spirolina, and BioZin with his grain and antihistamine with direction from my vet.
The hives went away again in mid June for a week and then returned. My vet gave my horse a shot of Dexamethasone and capsules if needed. The hives went away immediately, but returned five days later. I started him on the capsules. The hives went away after two days. I stopped the capsules as told by my vet. Five days later the hives started to return; I repeated the two days of capsules; hives gone. I am waiting for the next five days to see what happens. The hives return smaller and fewer each time. My vet suggests I start him on desensitizing shots prepared by the lab that tested him. He says this process only has a 60% cure rate, but I should try. Is there another process or professional I can try? We live in Virginia where it has been unusually hot and dry. Many people are having hive trouble, but not this severe. We moved here just before this, so I guess it is the region. HELP! I would appreciate your opinions and suggestion. – Thanks, SS
Dear SS,
Of all the skin conditions horses get, hives has to be one of the most difficult ones to deal with. You almost need to be Sherlock Holmes to figure out what causes it! On top of that, the medication regimen can be expensive and complicated and doesn’t always work or keep working. And your poor horse looks and feels miserable. You didn’t mention if yours was itchy as well as lumpy, but many are.
I like that you’re on products with omega-3 fatty acids, as research has shown they help maintain healthy skin and even support healing of certain skin conditions, like hives. I would also place MSM in this category. Another ingredient many horse owners have great success with is adaptogens such as the herbs found in APF. Until you can discover and remove the stimulus though, antihistamines and steroids will also be necessary. You may want to ask your veterinarian if a different kind of antihistamine or steroid might work better in your individual horse.
Since your horse never had hives before you moved to this new area, it does sound like something in the new environment is causing this reaction. The choices are many: something in his diet, something he’s inhaling, something he’s coming in contact with, etc. His hives could also be caused by a hypersensitivity to insects.
You can either systematically eliminate potential causes one by one and wait to see if he gets better or you can attempt to diagnose the cause by testing. Unfortunately, testing is controversial, as some feel the blood test your veterinarian has performed is not as useful as intradermal skin testing. Before you start the desensitizing injections based on results of the blood test, talk to your veterinarian about the pros and cons of intradermal skin testing. Or, ask him to help you get a second opinion at the nearest referral center, whether a private practice or University.
In the meantime, keep your horse as comfortable as possible. Give frequent cool baths—with or without a soothing shampoo or other product—and protect him from insects with a fan in his stall and a mask, sheet and leggings during the day.
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Lydia F. Gray, DVM MA, currently serves as the Medical Director/Staff Veterinarian for SmartPak Equine. Prior to joining SmartPak, Dr. Gray served as the first-ever Director of Owner Education for the American Association of Equine Practitioners. She has authored numerous articles in publications such as The Horse, Horse Illustrated, Western Horseman and a variety of veterinary journals and magazines. Dr. Gray is also a frequent speaker at horse expos, veterinary conventions and other locations. After graduating with honors from the University of Illinois College of Veterinary Medicine and receiving her Master's Degree in Interpersonal and Organizational Communication, she practiced at the Tremont Veterinary Clinic for several years. Dr Gray is active in the American Veterinary Medical Association and Illinois State Veterinary Medical Association and enjoys training and showing her trakehner Newman in her spare time. Find Dr. Gray on Google+: Find Dr. Gray on Google+
I,too, have a qtr horse that gets big-wheeled hives seasonally. He is allergic to gnats, that thrive in wet climate. Like clockwork, when it rains, the gnats hatch and he breaks out. I have had some success with vinegar, both as an oral treatment, and sprayed on as a ‘bug spray’. I feed apple cider vinegar, 2 cups per day. Then use clear vinegar mixed 2/3 vinegar with 1/3 water as a bug spray. I spray on morning and evenings, when gnats are most active. Be careful tho’, vinegar can sting in open wounds and eyes. It’s inexpensive by the case, and moderately effective.
This has to be a Virginia thing. Im having similar problems (though we arent this bad yet). Its so frustrating especially when out of 15 horses hes the only one.He gets hives, he molts entire areas of his coat. We go between medicating and bathing and blanketing and its just not a fun cycle.
My daughter’s Arab gelding has had hives since he received a vaccination in April! We are losing our minds trying to treat. I have learned you must be super careful with using the Dex. Horses on Dex are more prone to Laminitis and, if your horse is prone to ulcers, the Dex can aggravate the ulcers (sadly, we learned the hard way). If ulcers are an issue, make sure you give omeprazole along with Dex.
We have tried eliminating everything ( bedding, sheeting instead of fly spray, different hay, different barn) all to no avail. I was told not to waste money on the blood test but to do the intradermal. Of course, once allergens are identified, there is no guarantee they can be eliminated.
I am open to any other suggestions, I am now soaking his hay (miserable in winter). Had ulcers when we got him (just over a year ago), hives began with vaccination and are only kept away with Dex.