It's not uncommon to go out to the pasture and find your horse with a large, soft lump, probably due to bumping into something or getting kicked. The areas generally affected are along the front of the chest or breastbone area, along the sides of the ribs or flanks and on the haunches.
Occasionally, horses develop these swellings by hitting themselves--kicking at flies, for instance--or by the negligence of caretakers--turning a horse into a stall at too sharp an angle, for example, resulting in a bump or swelling on the shoulders or hips.
The swellings that develop can be quite large and initially feel like a fluid-filled sac or a water-balloon under the skin. Often, the skin itself is not damaged, though scrapes or signs of trauma may be evident. These swellings are usually warm to the touch.
Trauma that has damaged blood vessels that have begun to leak under the skin is called a hematoma. Hematomas can be distressingly large because the damaged blood vessels usually won't stop leaking until enough pressure has built up in the site. Hematomas may continue to swell for some time after the initial trauma.
The first step in treating these injuries is to apply pressure to the area, if possible. A bandage or wrap may be used. Direct pressure applied by hand may be all that is possible because the most prominent areas for hematoma formation are not easy to wrap.
Cold water hosing or ice pack application is another major treatment. The amount of pressure and cold applied to a hematoma during the first 24 hours will have a huge impact on the extent of the damage and on the time needed for recovery. Cold should be applied for 15 to 20 minutes, followed by a rest period of at least an hour. (Excessive cold application will fatigue the muscles in the blood vessels and more bleeding and swelling--not less--will result.)
Many times, hematomas will appear as very large, hanging pockets of fluid as gravity draws the fluid down. A few days after trauma, hematomas may hang down below the horse's pectorals (chest muscles) or on the belly and back legs.
The urge to drain these injuries is great; it is also usually wrong. When the fluid is simply removed via needle, the pressure on the damaged vessels and tissue is lessened, and the injured area begins to seep and ooze again.
Soon the hematoma is filled as before. Draining, then wrapping the area, can drastically improve hema-tomas, but this is not usually possible because of the location of the injury.
Whether to surgically open a hematoma is decided case-by-case. Many veterinarians are opposed for two reasons.
First, the risk of infection in these moist areas is considerable. Lancing will immediately reduce the size, but the open wound continues to leak for some time and keeping the area clean is a challenge.
Bacterial infections are common and potentially severe; blood is a perfect medium for the growth of bacteria.
Continual flushing is necessary and occasionally a veterinary surgeon will place a drain in the hematoma, usually a thin piece of plastic or latex-like material that allows fluid to collect and exit.
Second, despite taking a long time, most hematomas resolve on their own; give them some time, and leave them alone.
Hematomas go through a series of stages as they heal, and appropriate treatment along the way is important.
Cold hosing and pressure should be applied in the initial stages and continued as long as the area feels warm and soft to the touch.
Thereafter, the area will feel less squishy and more gel-like. During this stage, much of the free fluid present in blood or serum has been removed, and a thicker gel-like mass remains.
The gel is a mass of cells, fibrin clot and cellular debris. If left untreated, the horse will convert this material into fibrous tissue, possibly leaving a scar.
Massage, cold laser or other forms of deep tissue stimulation at this stage will reduce scar formation and help the horse maintain range of motion.
Ken Marcella, D.V.M., is based at the Chattahoo-chee Center in Canton, Ga.
It's what's inside that counts
Not all swellings are hematomas. If the skin is punctured, even by a hole too small to find, and if bacteria have entered, then the swelling is an abscess. This type of lump will be filled with a thicker, pus-like fluid that can range from white to yellow to red depending on the type of bacteria present. Frequently, there may be an unpleasant odor.
If the trauma causes tissue fluids to leak, then it is called a seroma. This fluid is thicker than water and honey-colored.