A variety of factors cause swollen legs in horses. The culprits behind swelling usually include fluid accumulation due to injury or infection, soft tissue damage caused by a sprain or strain, and a lack of blood flow due to damaged blood vessels. 

Dealing with swelling due to injuries or physical conditions can be frustrating for horse owners because it requires money, resources, and abstinence from competition. It is also distressing to watch your much-loved horse go through a great deal of pain and physical discomfort. Naturally, you want to do everything you can to prevent poor health and injury. 

In this article, we discuss the major causes of swelling in a horse’s leg and what you can do to keep the limbs of your horse in peak condition. This approach aims to improve limb health so your horse can fight injury and infection if it does occur. 

Major causes of swelling in your horse’s limbs

Cellulitis

Cellulitis is a very painful condition presenting a challenge for horse owners because it appears to come out of nowhere and progress quickly (within 6-12 hours). The rapid progression can quickly turn ugly with life-threatening complications. 

This condition is an inflammatory response to infection in the horse’s skin and the underlying tissues, usually initiated by bacteria that have entered through a break in the skin. The types of bacteria most commonly involved are Staphylococcus aureus and Streptococcus, though other bacteria can also be culprits.

Sometimes, the reason for cellulitis is obvious because there is a visible wound or injury to the skin. At other times, there appears to be no reason for it. At these times, you should turn your attention to possible poor hygiene, existing injuries that have not been fully treated, and a compromised immune system from a previous illness. Any conditions that allow bacteria to thrive and take advantage of a break in the skin can lead to cellulitis.

The horse’s immune system responds to this bacterial attack by sending neutrophils (white blood cells) to deal with the infection. This ‘extreme swelling’ response causes redness, warmth, and swelling.  

In severe cases, cellulitis can lead to systemic infection, with the horse showing signs of fever, lethargy, and lack of appetite.  

Preventative measures

Because cellulitis is such a painful condition, if possible everything should be done to avoid it from developing.  

One way of preventing or at least minimising the trauma to the soft tissues is to increase the health of the structures that make up your horse’s limbs. Muscle tissue, as well as the supporting structures such as the tendons, joints and ligaments can benefit greatly from the addition of a carnosine supplement such as the gel formulated by Chemipower and Tartu University. Backed by the work of over 800+ researches, CarnoGel accelerates muscle recovery and reduces the risk of injuries. It also improves tendon, joint and ligament health giving your horse the best chance of fighting off a condition like cellulitis.   

Rigorous cleaning of your horse’s stall and treating wounds, scratches, and bumps (even small ones) immediately can also have a big effect. If your horse has recently suffered from an overreach injury, put them under observation for the development of cellulitis since overreach wounds are prone to getting infected. 

Once cellulitis develops, get professional help immediately and apply cold therapy such as ice packs or water hosing while you wait for the appropriate treatment.

Lymphangitis

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Another potential cause of a swollen leg is lymphangitis.  It occurs when the lymphatic system, responsible for draining excess fluid from tissues, becomes inflamed and causes poor circulation. This leads to limb swelling and discomfort as fluid cannot flow freely back into the bloodstream, filtering out bacteria and other toxins. 

Much like cellulitis, lymphangitis occurs when the immune system responds to the increased presence of pathogens. This condition most commonly affects the hind leg and fluid leakage through the skin is common. Immediate medical attention and pain relief are required when you notice any heat, redness, or warmth on the hind legs to prevent this painful condition from spreading. 

Work horses and performance sports horses are prone to this condition because they are exposed to extensive periods of exercise, and short recovery times. The prevention of fluid build up in the hind limbs can be difficult but will be helped along by paying close attention to injuries, cuts, puncture wounds, and minor swelling that might occur. The health of your horse’s legs should always be of paramount importance. 

Joint, tendon, and ligament injuries

Leg swelling is a common sign of injury to the key supporting structures of the limbs. There is so much power in the limbs of a horse but maintaining the power depends on the condition of the muscles, joints, tendons, and ligaments. 

Ligaments are tough, elastic bands of connective tissue that connect bones to other bones at joints. While tendons are robust, fibrous cords that attach muscles to bones. They play a pivotal role in movement by transmitting the force generated by muscle contractions to the bones, thus facilitating motion. Tendons also act as shock absorbers and energy storage systems, particularly in the legs, where they help in energy-efficient locomotion, such as during galloping or jumping. An inflammatory condition that affects tendons is called tendonitis. Instead of causing pain, inflammation, and swelling in the soft tissues or lymph vessels, the tendons are affected. 

We previously mentioned that CarnoGel is an innovative support therapy for muscle, tendon, joint, and ligament health. Apart from its anti-inflammatory properties, it can also act as a pH buffer, reducing the negative effects of lactic acid and leading to better recovery after exercise. This greatly helps prevent injuries. 

Arthritis

Arthritis is a degenerative joint disease characterized by the breakdown of cartilage, the cushioning material at the joint surfaces. As the cartilage wears away, the bones begin to rub against each other, leading to pain, inflammation, and swelling. Osteoarthritis is the most common form of arthritis in horses, often resulting from the cumulative wear and tear on joints.

Swelling occurs because there is little or no cushioning between joints, and this causes structures to grind against one another. What begins as episodes of acute swelling after exercise turns into chronic swelling and inflammation. The surrounding tissues are affected as fluid builds up around the joint. 

You cannot reverse arthritis in older horses, but you can prevent it in young horses to some extent by using a carnosine gel, like CarnoGel, to maintain the health of joints, muscles, and soft tissues. Massaging the gel into your horse’s legs allows you to move any fluid forming in the tissues. If your horse already has arthritis, this can help relieve their discomfort. 

Edema

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Edema is a common reason for limb swelling and can range from mild to severe. It is the abnormal accumulation of fluid in tissues that leads to swelling. The development of edema is varied and should be monitored, as it may be a sign of a more serious issue such as kidney and heart problems or a severe allergic reaction.

The basic cause of edema is an imbalance in fluid exchange in the circulatory system. This imbalance is triggered for several reasons:

• Poor Circulation: Standing in one position for extended periods, especially in stalls, can impede blood flow and lymphatic drainage. This may be necessary because the horse has been injured and needs a period of rest but then leads to a secondary problem. 
• Kidney or Heart Problems: Systemic issues such as renal failure or heart disease can disrupt the body’s fluid balance, causing widespread edema, including in the legs. 
• Allergic Reactions: Allergens, whether from food, environment, or insect bites, can provoke an inflammatory response, resulting in localized or generalized edema.
• Infections: Bacterial infections can directly affect the tissues or the lymphatic system, leading to swelling.

The best remedy is prevention.

In this article, we have discussed the major causes of swelling in a horse’s leg as a way of showing that prevention is the best remedy. 

You cannot completely prevent injury or disease from occurring but you put a few basic preventative steps in place to keep your horse’s limbs in top physical condition. 

One of the aids we’ve suggested is a carnosine gel by Chemipower. Applying CarnoGel to your horse’s legs has many benefits such as:

• Reduces inflammation
• Increase muscle, tendon, joint, and ligament health
• Decreased recovery and downtime
• A decrease in muscle fatigue due to its pH buffering capacity 
• No side effects

Alongside good stall hygiene, prompt treatments of injuries and wounds, and the immediate management of conditions such as arthritis, cellulitis, and lymphangitis, carnosine provides a complete plan for the prevention of swelling in your horse’s limbs. This simple strategy will keep your horse happy, healthy and competition ready.