Of the many skin conditions horses can develop, sarcoids are the most common. The term "sarcoid" was first used in 1936 in South Africa as a way to distinguish this skin lesion from other tumors. Sarcoids are benign (nonmetastatic) skin cancer believed to be caused by papillomavirus infection. They affect up to 11.5% of all horses. Sarcoids usually appear as rough, raised, hairless patches or nodules on the skin that are not painful or itchy. Some sarcoids are protruding, moveable masses with overlying skin still intact. The tumors are cosmetically unappealing and, depending on their location, can interfere with the function of the horse. But in most cases, the prognosis for affected horses is very good and some sarcoids resolve without any intervention. Effective treatments are available, including surgical removal, immunotherapy, cryotherapy, and laser surgery. However, sarcoids have a high rate of recurrence in horses.

Horses are prone to a number of different skin conditions and diseases. Some are minor and resolve on their own, while others can be much more serious. Skin conditions may affect localized areas on the horse, such as the legs or abdomen, or they can be widespread, affecting multiple areas. Symptoms may include itchiness, swelling, hair loss, skin flaking, and more. Learning to recognize various equine skin diseases is important to take the appropriate actions needed to resolve the problem or to manage the horse to keep them more comfortable.

Pain is something that all horses deal with at some point in their lives. Horses can experience pain for many different reasons, including injury, illness, or a result of surgery. For example, castration is the most common surgical procedure performed on horses and is associated with significant post-operative pain. Acute colic is another common painful experience for horses. Pain is also commonly associated with degenerative joint disease, laminitis, gastric ulcers, and hoof issues. Unlike humans, horses don't always show it when they are experiencing pain, or they may only display subtle signs of discomfort. This is because, as prey animals, they have evolved to hide signs of pain and weakness in the presence of predators.

Stagnation edema, also known as stocking up, is a common cause of leg swelling in stabled horses. It occurs due to impaired circulation from periods of reduced activity. This short-lasting form of edema typically affects both hind limbs and causes swelling from the coronary band up to the hock. Occasionally, it occurs in the forelegs as well. Stocking up is also called distal limb edema because it affects to lower portion of the limbs. Another term for stocking up is pitting edema. This is because when pressure is applied to the area, a pit or indentation will remain temporarily. Stocking up results from the pooling of lymph, a clear fluid that circulates in the lymphatic vessels. Sometimes this circulation is compromised allowing fluid to accumulate. This typically occurs if blood flow and lymphatic drainage are impaired.

Equine pneumonia is a common respiratory illness that can be life-threatening in young horses. It can affect different parts of the horse’s lungs and may cause varied symptoms. Pneumonia refers to an infection in the lungs in which tissues become inflamed, and the air sacs fill with fluid or pus. Horses affected by pneumonia can experience cough, fever, weakness and difficulty breathing. Pneumonia can affect horses of all ages, but it is most prevalent in 2 and 3-year-old horses. It is also the most common cause of illness and death in foals between 1-6 months of age.

Equine sinusitis is the most common disease affecting the paranasal sinuses in horses. Sinusitis is an inflammatory condition that often involves excessive nasal discharge. Horses with sinus diseases can also experience swelling in the face or reduced appetite. The causes of sinusitis vary but can include dental disease or bacterial infection of the upper respiratory tract. Treatment for this condition often presents a challenge to veterinarians because of the large size of the horse's sinus structures, their complex anatomy, difficulties accessing the area, and the advanced state of the disease before a diagnosis is made.

Strangles, also known as equine distemper, is a highly contagious disease caused by the bacteria Streptococcus equi. Young horses are most susceptible to developing strangles disease. This condition most commonly occurs in horses under the age of two. The name "strangles" comes from the common sign of dysphagia or trouble swallowing that some horses experience, caused by enlarged lymph nodes.

Uveitis in horses is a condition in which the uvea layer of the eye becomes inflamed. It is the most common cause of blindness in horses. It is estimated that as many as 25% of horses worldwide are affected by some form of uveitis.

Sweet Itch is a common skin condition in horses that is caused by an allergic reaction to insect bites. It is also known by the names Queensland itch, summer dermatitis, insect-bite hypersensitivity, summer eczema, recurrent seasonal pruritus, and equine Culicoides sensitivity.

Bartonella is a type of bacteria that can infect humans as well as other mammals, including horses and donkeys. The resulting infection, known as bartonellosis, has been documented in many regions throughout the world.

Equine Protozoal Myeloencephalitis (EPM) is an infectious disease of the horse’s central nervous system. It is one of the most difficult diseases for veterinarians to diagnose because it often mimics other conditions and has a wide range of symptoms that affect multiple parts of the horse’s body.

Physitis is the most common developmental disease that affects the bones of growing horses. This condition involves swelling around the growth plates (physes) of long bones in a young horse’s legs. It can lead to pain, stiffness in the joints, and lameness.

An overabundance of fat along the top of the neckline, otherwise known as cresty neck, is an indicator of metabolic problems in your horse. In fact, researchers believe this type of regional fat deposit (nuchal crest adiposity) is a strong indicator of equine metabolic syndrome (EMS).