Looking for ways to reduce swelling in your horse’s legs? Several factors can lead to leg swelling in horses, ranging from mild conditions such as “stocking up” to more severe issues such as cellulitis.

If your horse is experiencing limb swelling, your first priority should be consulting with your veterinarian to identify and treat the underlying cause. Then, you can implement several management techniques to reduce the swelling.

Swelling can affect any part of the horse’s leg but is most common in the lower limbs. Swelling may also occur around joints such as the knee or the hock, and, in rare cases, can also affect the upper limb.

Cold therapy, leg wraps, massage, anti-inflammatory medications, and sweat bandages are just some of the strategies used to address leg swelling in horses. Regular exercise, good stall hygiene, and avoiding prolonged periods of inactivity can also help prevent swelling.

Common Causes of Limb Swelling in Horses

Swelling in a horse’s leg is the accumulation of excess fluid in the tissues or joints. If the swelling occurs outside of a joint, it is referred to as edema. When swelling happens inside a joint because of increased fluid within the joint capsule, it is known as effusion.

Limb swelling in horses can be caused by a variety of factors and conditions, including inflammation, injury, infection, poor circulation, immune responses, or other underlying health conditions.

Some of the most common causes of limb swelling in horses are detailed below:

Stocking Up (Stagnation Edema)

Stocking up refers to swelling that develops in the lower legs due to inactivity, usually when a horse is stalled for long periods of time. Stocking up typically affects the hind limbs, but occasionally affects the forelimbs as well. [1]

This condition arises when a horse’s circulatory system becomes less efficient due to reduced movement, leading to fluid accumulation in the legs. [1]

Stocking up does not appear to be painful for horses, but it may lead to mild stiffness and reluctance to move. Affected horses generally do not suffer other adverse effects and the condition is easily resolved with light activity in most cases.

Trauma

Any type of trauma to the leg can lead to acute swelling, including contusions (bruises) from impact, abrasions from rough surfaces, puncture wounds from stepping on sharp objects, or overexertion injuries from intense exercise or jumping.

If a laceration (skin wound) is present or indications of a bite wound, such as a snake bite, consult your veterinarian. Immediate treatment may be required to prevent an infection.

Allergic Reaction

Horses can also experience limb swelling as a result of an allergic reaction to environmental factors, such as insect bites, plant allergens, or chemicals found in bedding or grooming products.

A common allergic reaction in horses is Type 1 photosensitization (photodermatitis). In this condition, photosensitive substances accumulate in the skin and react with sunlight, resulting in inflammation and painful skin swelling. [2]

Photosensitization is most common in horses with unpigmented or lightly colored areas of skin. Plants that can trigger a photosensitive reaction include:

  • St. John’s wort
  • Bishop’s weed
  • Clover
  • Buckwheat

In some cases, photosensitization may be triggered by alfalfa hay. [2]

Horses can also develop Type II photosensitization, which occurs due to liver damage. This condition can also lead to swelling and dermatitis of the lower limb(s). If this condition is suspected, consult your veterinarian right away. [2]

Bowed Tendon

A bowed tendon is a condition in horses that involves the tearing of the superficial digital flexor tendon in the middle of the cannon bone area. This injury is characterized by a bow-like swelling on the back of the leg, extending from the knee down to the fetlock. [3]

A bowed tendon will lead to acute swelling, heat, and pain. The horse may or may not show lameness. Ultrasonographic evaluation by your veterinarian can determine the severity of the tendon damage. [3]

Bowed tendons are a serious injury and can take a long time to heal. Horses typically need stall rest and restricted exercise for at least two months and possibly up to eight months, depending on the severity of the injury. [3]

However, most horses can recover and return to athletic performance if the injury is given enough time to properly heal. [3]

Ligament Injuries

Horses can also sustain ligament injuries, such as strains or damage resulting from trauma or overuse, which can cause swelling in the lower leg. A horse suffering from a ligament injury can exhibit mild to severe lameness with heat and pain present in the affected area. [4]

An example of a common ligament injury in horses is bucked shins or splints. This injury is caused by strain placed on the ligament between the cannon bone and splint bones. [5]

As a horse ages, this ligament naturally ossifies. Jumping, running, and/or hard work can irritate the area, leading to pain. [5]

Splints usually affect the inside part of the foreleg and can result in lameness and swelling. This condition often occurs in young horses in hard training, between the ages of 2 to 5. After the ligament has fully ossified, the swelling and soreness usually disappear. [5]

Windpuffs

Windpuffs are soft, fluid-filled swellings of the fetlock region usually caused by excessive strain. They can occur in both the front and back legs.

Windpuffs generally do not cause pain or lameness unless there is damage to the underlying tendon sheath.

Pastern Dermatitis

Pastern dermatitis is a skin condition often seen in horses with white legs and in many draft breeds. It arises from multiple causes such as bacterial, fungal, or mite infestations, leading to swelling and discomfort in the lower leg. [6]

Pastern dermatitis is more common in the hind legs and can give rise to secondary infections requiring medical intervention. [6]

Cellulitis

Cellulitis is a serious infection of the subcutaneous tissue of the horse’s leg. This condition typically affects just one leg and often arises as a secondary complication following a wound or the spread of a bacterial infection from another part of the body. [7]

Cellulitis in horses involves considerable swelling and severe lameness. The condition is considered a medical emergency and often develops rapidly. The affected leg may be warm and painful to the touch and the horse may also have a fever and be lethargic. [7]

If the condition is not promptly addressed, it can rapidly progress, leading to the leg swelling to 2-3 times its normal size. This condition also poses a serious health risk and can be life-threatening. The primary treatment for cellulitis involves the use of antimicrobial therapy. [7]

Lymphangitis

Lymphangitis (big leg disease) is a severe condition characterized by swelling in the lower limbs, disrupting normal fluid circulation and leading to fluid leakage into the surrounding tissues. This results in extreme swelling in one hind leg, accompanied by significant pain and fever. [1]

Horses affected by lymphangitis often exhibit clear signs of depression. Some horses show signs of trembling, rapid breathing, and/or sweating. [1]

Lymphangitis is caused by a bacterial or fungal infection, typically associated with a wound to the leg. Pathogens identified in cases of lymphangitis include Staphylococcus, Streptococcus, or E. coli species.

The bacteria reproduce quickly in the lymphatic system, leading to an inflammatory reaction. The lymph nodes can get overwhelmed and become infected as well. [2]

Chronic Progressive Lymphedema

Chronic progressive lymphedema (CPL) is another condition that results in swelling of the lower leg. CPL is most common in draft breeds but can affect non-draft breeds as well.

Secondary bacterial and parasitic infections can complicate CPL lesions and worsen symptoms. [8][9]

Other Causes of Limb Swelling

Leg swelling in horses can also be caused by other conditions including:

  • Lung disease
  • Purpura Haemorrhagica (a complication of strangles)
  • Kidney disease
  • Liver disease
  • Heart failure
  • Thyroid disease
  • Damaged blood vessels or nerves

These conditions are considerably less common. If the horse is otherwise in good health, the limb swelling is likely attributable to a less severe issue.

9 Ways to Reduce Swelling in Your Horse’s Legs

The best way to reduce swelling in your horse’s legs depends on what is causing the swelling in the first place. Prompt diagnosis and treatment of any underlying infections or conditions is important to prevent secondary complications.

Consult with your veterinarian to determine the best treatment plan depending on your horse’s individual status. Once you have addressed any underlying health concerns, there are a number of tried-and-true ways to reduce ge