Last Updated on February 19, 2022 by Allison Price
This microbial infection can be treated quickly by taking immediate action.
Although your horse seemed fine last night when you left him alone in his stall, this morning, he is pacing in the corner and refusing to get out. You quickly notice the problem. His left hind leg has doubled in size from the hoof to the hock. Cellulitis is a serious condition in horses that causes extreme swelling.
Emma Adam, BVetMed and PhD, DACVIM, DACVS at the Gluck Equine Research Center in Kentucky, says that cellulitis should be treated as soon as possible. Dr. Adam explains everything you need to know regarding cellulitis in this article.
Both cellulitis and lymphangitis, which are closely related, can produce similar symptoms. Both are caused by microbial infection. Cellulitis is caused by bacteria infecting the skin’s tissues; lymphangitis is caused when bacteria infects the lymphatic ducts which drain fluid from the limb. These terms are often interchangeable, and the symptoms and treatments are nearly identical. Dr. Adam says that horses need a veterinarian in both cases.
Cellulitis is a microbial infection that causes extreme leg swelling and loss in normal contours.
Sudden and severe
Cellulitis is a fast-growing condition that can often be treated in less than 12 hours. Cellulitis is distinguished from other types in leg swelling by several factors.
* Extent. Dr. Adam states that the’stovepipe leg’, which has extensive swelling and loss in normal contours, can be a classic sign. “Swelling due to injuries is usually more localized.” Swollen limbs may extend from the foot to the stifle.
* Distribution. Typically, the swelling occurs in one leg. It is most common in the hind leg. It is less common in the front, or in multiple limbs, unless there are other causes such as infection wounds. It is not clear why the hind limbs are more affected than the front. Dr. Adam said that kicks may make the hind legs more susceptible to injury that triggers the condition. Also, the hind legs might be more difficult to clean properly so small injuries or skin conditions can be overlooked.
* Heat. Cellulitis makes a leg feel warm to the touch. Cellulitis can cause skin to feel taut, stretched, or even ooze fluid.
* Pain. cellulitis is very painful and horses may not be able to tolerate pressure on the swollen leg. He might resist handling the leg or be unable to walk on it.
* Fever. A high temperature is quite common in severe cases. You may notice the horse seeming depressed or ignoring his food.
These infections usually involve Staphylococcus or Streptococcus bacteria, but other types may also be involved. These bacteria can be found in the horse’s environment and on their skin. They can cause severe chapping and other problems by causing a skin break. Sometimes, a break in the skin cannot be found. However, the skin can still be damaged by blunt trauma. It is not clear how it starts in these cases. Dr. Adam suggests that blunt force trauma may cause damage to the circulation, or that there is a small break in the skin.
Once bacteria is infected, they multiply and create toxins that cause inflammation and damage to the blood and lymphatic systems. The damaged blood vessels leak fluid and the lymphatic system is unable to remove it. Further restricting circulation is further caused by swelling.
Cellulitis-causing bacteria can get into the skin through a cut or nick, such as pastern dertitis (scratches). Cellulitis can be caused by bacteria that has been infected once they have spread and produced toxins that cause inflammation and widespread damage.
Cellulitis can cause permanent injury and leave horses with an intractable limp. The most serious risks are those that can lead to death. These are the most dangerous:
* Laminitis. Horses with severe sore left hind legs will keep their weight on the right hind, or the contralateral leg. The risk of developing weight-bearing laminitis in the contralateral leg increases with time. Laminitis refers to inflammation of the laminae within the hoof wall, which are the structures that attach the hoof to a pedal bone (coffin bones). This can lead to pain or loss of attachment between the hoof wall and the coffin bone. In cases of damage that is circumferential, this can cause rotation of the coffin bones or sinking of coffin bones. This could lead to the loss of structural integrity and the penetration of the soles of the hoof. Cellulitis can also be caused by impaired circulation. Laminitis can be a very painful condition and may even lead to euthanasia.
* Dermal necrosis. Bacterial toxicants can cause severe skin damage. Impaired circulation also reduces oxygen supply and other essential nutrients to skin cells. The skin becomes dry and sloughs off, leaving the tissues exposed below. Skin sloughing can lead to tendon sheaths and septic joints. Cellulitis-associated bacteria can cause toxins that can lead to multiple organ failure, sepsis, and septic shock syndrome.
Dr. Adam advises that you should nip it in the bud. It can be difficult to control if you leave it for more than a few days.
What to do
If you suspect cellulitis, call your veterinarian immediately. The goal of treatment is to minimize damage and prevent complications. It involves stopping the infection, decreasing swelling, and getting the horse as comfortable as possible.
* Antimicrobial medications. Your vet will prescribe the appropriate antibiotic, but your veterinarian may also request samples to culture the bacteria. An ultrasound scan may be able to locate the area where fluid can possibly be taken for testing to determine the source of the infection. “Historically, we were reluctant to draw fluid for testing because it could cause the skin to split if it was punctured. Dr. Adam says that there is no evidence to support this. The test results can be used by the vet to determine the best antimicrobial drug.
* Anti-inflammatory medications. Systemic, nonsteroidal anti-inflammatory medicines such as flunixin and phenylbutazone have two main functions. They reduce swelling and ease discomfort. If necessary, your veterinarian may recommend a topical anti-inflammatory like diclofenac gel or cream. This can be applied to the skin around the affected area. Dr. Adam recommends that you use these products with caution, particularly if the affected limb needs to be bandaged due to the fact that the skin already has poor circulation and swelling.
* Cold therapy. cold reduces swelling and slows down bacterial activity. The most effective form of ice is ice boots or ice packs. Ice may be applied to the limb for 20-30 minutes each hour, or according to a veterinarian-determined schedule. Dr. Adam warns that you should change the ice often. Dr. Adam warns that ice packs can hold heat in the legs once they have warmed up. It is hard to overstate the impact of cooling the leg. Use a gentle stream of water, not a strong blast. The skin can easily be damaged because it is stressed, swollen and attacked by bacteria toxins. After hosing, dry the legs gently.
Ice therapy is a cold therapy that reduces swelling and inhibits bacteria in cellulitis. The most effective form of ice therapy is ice boots or ice packs.
Cellulitis treatment may include ice for 20-30 minutes per hour, or according to a veterinarian’s schedule.
Courtesy, Soft-Ride Comfort Boots
* Stabilizing. Supportive Wraps. These wraps can be used to reduce swelling but may not work well in cellulitis. They might also hold heat. The area above the bandage can often swell after it is removed. This can lead to problems. The horse may not tolerate a pressure wrap because the horse’s limb may be so tender in the beginning stages. Dr. Adam suggests that you wrap the leg lightly with a compressive layer, then put it in the iceboot.
* Movement. Activity stimulates circulation and speeds up recovery. When the horse is able to walk and has stopped causing pain, you can place him in a large stall. Hand-walking him can be done for a few minutes, maybe five to ten minutes.
You should monitor the horse’s condition. Dr. Adam says that the horse should improve with treatment. It’s time for additional treatment if the swelling does not decrease or the horse’s comfort level does not improve after just a few days.
Ultrasound scans are a great way for your veterinarian to monitor the progress of the condition and find pockets of infection. A range of therapies can be used if the initial treatment fails to produce results.
* Switching drugs. This step is usually considered in cases where the horse has developed resistance to the antimicrobial treatment he has been receiving. Cellulitis can be fatal. Dr. Adam states that antibiotics will not work unless they are delivered directly to the source of the infection. The swelling and disruption in blood flow caused by cellulitis can make this difficult.” Switching antibiotics is not a risk-free choice, and the use of multiple antibiotic drugs can increase the risk for antibiotic-associated diarrhea.
* More effective drug delivery methods. IV regional perfusion is one method to deliver more medication to the area. After the horse is sedated, the veterinarian places a tourniquet over the affected area. Then, the veterinarian injects the appropriate diluted antimicrobial into the vein below the tourniquet. The tourniquet can be removed after about 30 minutes. The veterinarian will determine the best schedule for the procedure, but only if the limb is able to tolerate it.
* Surgical drainage. Sometimes, infection can persist even after treatment. Dr. Adam states that drainage allows for better circulation at these hard-to-reach areas. Dr. Adam says that a recent case study showed that surgically draining infected pockets can improve circulation.
* Next-level pain relief. Dr. Adam points out that the longer the horse is without using the affected leg, the greater the chance of contralateral laminitis. If NSAIDs fail to work, the veterinarian may recommend a variety of pain meds including opioids. These can be administered either locally or systemically. These medications can be administered by epidural injection at the tailhead for hind-limb cellulitis. For pain relief, systemically, you can apply fentanyl transdermal patch to normal skin. These patches should be changed every 48-72 hours.
There are many adjunct therapies that can be used to help horses with cellulitis. Hyperbaric oxygen therapy is an option that can be found at some rehab centers and clinics. Each horse spends about an hour each day in a chamber that allows them to breathe pure oxygen at two- or three times the atmospheric pressure. The treatment improves oxygen delivery to tissues, decreases swelling, and increases the effectiveness of antibiotics.
It is likely that the horse has chronic cellulitis, lymphangitis, or both. Horses with acute cases of chronic cellulitis or lymphangitis are often unable to bear weight due to severe pain. Sluggish circulation can lead to skin disease in horses, as shown here with the weeping sore.
Paula da Silva/arnd.nl
Cellulitis is usually treated quickly and horses often recover within days. If the infection is severe or if treatment takes longer than 24 hours or fails to bring about improvement, then the outlook should be more cautious. In these cases, the risk of tissue and circulation damage increases and may lead to permanent damage.
Dr. Adam states that even if the horse is able to make a full recovery and return to work, the affected leg might not fully recover its normal contour. If there is persistent swelling, it could indicate that the horse has suffered permanent damage.
Recurrent episodes may occur in horses who have experienced cellulitis once. These horses may benefit from as much time out as possible, as activity encourages circulation in the legs. Stalled horses may benefit from standing wraps to reduce puffiness.
A good horsemanship is the best way for you to protect yourself from a second or third attack of cellulitis. Dr. Adam states that cellulitis can be linked to hygiene in human medicine. Although the connection isn’t clear in horses, it makes sense that hygiene could play a role. Mud, muck, and dampness can irritate skin, making it prone to infection. So:
* Pay attention to the feet and legs of your horse and be meticulous about their skin and coat. After bathing, dry your legs well.
* Pay attention to skin irritations and cuts and be sure to check regularly. Even the smallest cuts and nicks should be treated.
Dr. Adam states that cellulitis is best treated immediately you feel it. Calling your doctor is a great value for money, especially when you consider the serious consequences that could result if you let it get away.
Sidebar: Cellulitis and…
Cellulitis is the most common cause of swelling in the legs of horses, but it’s not the only one. These are the three most common.
Edema is the accumulation of fluid in the lower legs, usually in one or both of the hind legs. The swelling is not painful and doesn’t make the horse lame. A slight depression will remain for a few seconds if you press the horse with your fingertip. Horses can stock up when they are stalled due to inactivity which slows down circulation and allows fluid to build up. The swelling is generally reduced by activity.
Windpuffs appear around the ankles and around the flexor tendon (the main tendons at the back) and are soft, fluctuant swellings. These fluid-filled swellings are caused by fluid that builds up in the synovial sheaths (the casings that surround the tendons) and the fetlock joints. They are usually thought to be due to wear and tear on the tendon or joint. Windpuffs should not be considered a problem as long as they are soft, cool, and not painful. However, heat, soreness, or lameness could indicate more serious issues.
Injuries can cause swelling and other symptoms. Injuries can cause blood and lymph fluid to leak into the tissues. Body chemicals can trigger inflammation, which causes heat and soreness. The injury site is the most likely to experience swelling.
Minor scrapes can lead to broken bones and torn tendon. If the horse is in pain, lame, or experiencing significant discomfort, he should be seen immediately by a veterinarian. Even a minor cut that can be treated with first aid should be kept clean, dry, and checked for signs of infection, heat, pain, swelling, or discharge that lasts more than a few days.