Chronic itch, hives??

Question
I have a coming 3 year old warmblood who has had small bumps and tiny scabs under his hair since I bought him.(I think it is hives) They are all over his body really and I see him biting at his knees and ankles.  He has recently lost hair in an area of his flank and another by his front elbow in front of the girth area. He had not previously lost hair, but you could see the hairs not quite lying flat in the areas of the hives.  They have not changed significantly in the 8 months  I have had him.  I did give him a 3-4 day dose of a steroid once which eliminated the hives for the duration of the medication, but they came right back.  Is there anything else I can do to control these hives?  He is on grass hay, no alfalfa, and grass hay pellets, Safe Choice and Empower.  He had a similar diet at the farm where he was raised, but there has been no significant change in his hives when he was there vs here.  The lady told me that the bumps were bug bites, but I know now they were not.   thanks, Amy

Answer
Dear Amy:

I really dont think these are hives per se. Hives usually show up as large coalescing areas of edema that stay for several hours and then go away. they can and do recur though. The scabbing you describe is not characteristic of hives. It suggests that these areas of skin are breaking open and then healing byu scabbing over. Although your friend may be wrong in regards to this being just do to insects, she is not off base in suggesting that the response is similar to that seen to insect allergies. I believe you horse probably has a skin allergy, could be due to something he comes into contact with or something he ingests or even inhales. This suggests an environmental irritant that he has developed alleergy to. His response to the steroids and the itching also support this possiblity. I recommend changing things in the environment to try to control this and may eliminate the exposure to what he is responding to. Also, if you require further evidence of a diagnosis, I recommend that a vet get a skin biopsy of the affected areas. It is very easy to do. A change in feed and or hay source may also be necessary. Also, if he is in the barn, there could be dust, molds or other irritants he has developed allergies to. Remember, he can also have allergies to more than one thing and a horse that develops allergies often does exibit the problem to several things. Insects are also a very common cause, but Im not suggesting this is the ONLY cause- but insect alllergy is VERY common in my experience and may be one of his allergies. These conditions are difficult to manage as many horses are allergic in the skin to many things and its difficult to eliminate all of them from their access. However, often, with continuous exposure, these horses may develop tolerance to the irritants and the itching and skin lesions may go away with time (months or maybe years). Signs gradually improve. Id recommend using the steroids to control things when the signs are worst and change the environment he is exposed to piece by piece- the pasture, the beddding, the barn, the feed etc. Finally, I also recommend confirming this suspicion with a biopsy as it will also tell you if this could be due to something else. God luck. I know this is alot to digest and its not always easy to manage. Feel free to contact me with any further questions. Happy new year.