By Megan Williams, DVM
Horses, like kids on a playground,
seem to have a continuous array of lumps and bumps on them at various times,
and in various places. It’s a rare
horse that you don’t find some sort of lump when running your hand over
them. Quite often, these lumps are
benign, or have been there for years without change and are really nothing to
be concerned about. That said
there are times that a horse can develop a mass that can have severe
consequences for the health of the animal. The problem sometimes lays in the ability to determine when
that “lump” is significant and needs to be investigated or when it can be
quietly ignored. Whenever a new
mass is found on a horse, there is reason for concern, as there are a number of
possibilities for a lump on your horse that shows up seemingly overnight.
In general, if your horse develops
a single lump of any kind acutely (within hours to days), there are a number of
possible causes. A hematoma or
seroma is the result of blood or serum “leaking” under the skin to form a
mass. These are unsightly, and
often the horse will be tender to palpation of the region. By themselves, these masses are of
little concern, and the body will work its magic and resorb the fluid with us
doing little to no work. However,
if even a small amount of bacteria enters the seroma or hematoma, it is a rich
breeding ground and they will multiply quickly to form an abscess. Once an abscess forms it is far more important
that the mass be investigated and treated, especially if an outcome with
minimal scarring is desired. Lumps
found on the lower limbs can have soft tissue implications, and may also show
up along with a new lameness.
There are many tendons and tendon sheaths that will change in shape when
excessive strain is placed on them, causing them to “bow”, and resulting in a
lump on the back of a horse’s leg.
Joints themselves can have small out-pouching in places you may not have
normally considered, and should be treated with extreme care.
What about the horse that comes in
from the field and is covered in lumps and bumps from nose to tail? Immune reactions, such as allergies are
quite common in the horse, and can happen very quickly. One of the most common situations where
a horse develops “hives” all over its body is during a reaction to fly (Cullicoides) bites. Keeping the horse stalled when flies
are out, providing fans and a fly sheet can all help to ameliorate the skin’s
reaction. Unfortunately, this may
not always be the case, and horse, like humans, can have a wide array of
allergies, be it a contact allergy to a type of feed or bedding, or simply to
the latest pollen that is floating through the Florida breeze. These animals will not find relief
until the causative agent is removed, or treatment is started. In severe cases,
the reaction can get out of control and may cause the horse to experience
difficulty breathing, or moving if their legs swell too much. Careful monitoring is very important.
Often, when seeing a new lump or
mass on a horse, people are concerned about cancer. Although certain types of neoplasia (cancer) can develop
within a few weeks and grow quickly, these are rare in the horse. Many horses, especially older grey
horses, develop benign melanomas.
These show up most often under the tail and along the perineum or
vulva. Other common places to find
them are along the neck, behind the jaw, or under the ear. As a benign tumour,
these are often best treated with “benign neglect”, meaning that we just leave
them alone. If the masses continue
to grow and become a functional problem, they can be removed or treated with
chemotherapeutic agents.
No matter what the cause of the
random lump found on a horse, having them looked at by your veterinarian will
help provide a direction for how to treat it, and deal with any possible
similar lumps and bumps that may arise in the future.
Contact Surgi-Care Center for Horses at 813-643-7177 or email Dr. Leann Kuebelbeck at lkuebelbeck@surgi-carecenter.com with any questions regarding this topic.
This article originally appeared in Horse & Pony
magazine in November, 2011 and is reprinted with their permission.