Eosinphilic Granuloma Complex in Horses

Several things cause these lesions, with insect bites being one of the most obvious. But pressure from the tack and saddle areas can cause these lumps to develop as well. Your horse may develop many of these lumps over its body while other areas remain smooth. Allergies may be a cause, and it is a problem when these lumps ulcerate. Other lumps can become very hard because of calcification and these are quite hard to treat.

Equine eosinophilic granuloma is really a common condition in horses with lesions of various sizes occurring on the neck body and back of your horse.

• Pressure (often these lumps occur in high pressure areas like saddle and tack areas)
• More prevalent in the warmer season
• Allergies or environmental causes 
• Hypersensitivity
• Collagen degeneration
• Trauma or injury 
• Insect bites

The simplest solution is to leave the nodules alone unless they are bothering your horse, such as when you ride him. As they can be a reaction to insect biting, using a veterinary grade insect repellent may help. Keeping your horse covered with a light cover may deter insects. If the bumps are bothering your horse or they continue to enlarge, an injection of a steroid can shrink them. It may take two or three injections to achieve this but it is worth a try. If they don’t shrink and they are in an area where they worry your horse, you can get them surgically removed. On occasion, they may rub open and cause ulceration. This will need cleaning and medicating by the veterinarian. After treatment, the dressing will need to be kept clean and covered until healing. This condition is usually harmless although it may affect the way your horse looks. If your horse competes in shows, then you will need to talk to your veterinarian to discuss how these can be cleared up.

If there are only a few nodules or lumps, then leaving them to heal themselves may be best. If your horse has had steroid injections to shrink them, he will recover easily at home. Your veterinarian may suggest keeping your horse covered against fly or biting insects, and may prescribe an insect repellent to use. Your horse’s diet may need adjusting and your veterinarian will be able to suggest some alternative feed; this may help your horse if it is having an allergic reaction. If you get the lesions surgically removed, at home care will include keeping the area covered and protected against insects and infection. Usually with this condition, healing or control is excellent.