Swollen Leg

Diseases and conditions image
Diseases and conditions image EquiMed

Also Known As

Cellulitis, Lymphangitis


Discovering that a horse has a swollen leg is a common experience among horse owners. Swellings often develop over night or while a horse is in the pasture and are noticed only when the owner is getting ready to ride or train the horse. More serious swellings are accompanied by sudden lameness that immediately serves as a warning that something is seriously wrong with the horse's leg or legs.

A swollen leg can be the result of injury or disease. When one leg is involved, the swelling is usually the result of a localized infection. Sometimes a wound is obvious, but often a tiny puncture wound or a small wound in the foot will cause swelling of the entire leg.

In cases where all four legs are involved, heart failure, equine purpura hemorrhagica, and other allergies and diseases are possibilities.

Cellulitis is the technical term for infection of the tissues that causes a swelling in a horse. In severe cases, where the lymphatic system becomes involved, lymphangitis is the diagnosis. Inflammation of the lymphatics, the body's drainage channels that carry fluid towards the heart, become inflamed and blocked. Fluid then accumulates in the body or in the legs.

In any case, a swollen leg calls for a veterinarian's help in diagnosing and treating the problem, as well as in preventing complications.


  • Swollen leg or legs
  • Stiffness and reluctance to move
  • Lameness
  • Leg is sensitive to touch
  • A wound that oozes fluid or pus
  • Fever and/or heat in the affected limb
  • Depression
  • Tiny hemorrhages on lips, gums, or mucous membranes


Infection in the leg or foot and generalized illness, such as a heart condition, are the two main causes of swollen legs. In cases of generalized illnesses, all four limbs may be affected. If the swelling is caused by a localized wound that has become infected, or if lymphangitis is present, only one limb may be affected.

Lymphangitis occurs when a bacterial infection enters the lymph vessels through a wound in the lower leg, causing inflammation. This inflammation spreads through the lymphatic vessels, obstructing lymphatic flow and causing the vessels to swell and leak fluid. This results in extreme swelling of the leg.

Bacteria, foreign substances, or inorganic material that enters the system through a wound are usually the causes of infections that lead to a swollen leg.

In some cases, horses that are overworked will have some limb swelling, but without associated lameness or pain. In those cases, stall rest will help resolve the condition. If there is any question about the cause of the swelling, a veterinarian should be consulted.


Prompt attention anytime a horse appears to have an injury to the legs, exhibits any degree of lameness, or has swelling in the legs can help prevent complications and reduce healing time. A daily inspection of the horse's limbs and body will help catch even minor injuries or mild degrees of lameness in time to prevent more serious complications.


Any injury to the lower leg should be promptly cleaned and an antiseptic wound dressing applied. Depending on the location, it may also be bandaged or wrapped. If a puncture wound is present, a veterinarian should be called to treat the wound and to administer tetanus antitoxin and tetanus toxoid, depending on the vaccination background of the horse.

If lymphangitis is suspected, treatment will go beyond local wound therapy and include systemic antibiotics, given for a length of time determined by the veterinarian. If ulcerative lymphangitis is diagnosed, the limb injuries will need to be cleaned and disinfected, as will the entire stable area.

Antimicrobials and anti-inflammatories to combat the infection will be given. Physical therapy, to prevent severe lameness, is often recommended, along with hydrotherapy, wraps, and the administration of non-steroidal anti-inflammatory drugs.

Dig Deeper

This section contains articles specially selected by EquiMed staff for visitors wanting more information about this disease or condition. These articles are copyrighted by their respective owners and are available to you courtesy of EquiMed

About the Author

EquiMed Staff

EquiMed staff writers team up to provide articles that require periodic updates based on evolving methods of equine healthcare. Compendia articles, core healthcare topics and more are written and updated as a group effort. Our review process includes an important veterinarian review, helping to assure the content is consistent with the latest understanding from a medical professional.