Skin Conditions in Horses

The skin consists of three layers (the epidermis, dermis, and hypodermis) and is the body’s first line of defence against disease causing agents (pathogens).  The skin also has a role in sensory perception, excretion, and temperature regulation.

Common skin diseases:

  • Greasy heel/mud fever (commonly caused by Dermatophilus congolensis)
  • Rain scald (commonly caused by Dermatophilus congolensis)
  • Ring worm (commonly caused by Microsporum gypseum)
  • Girth itch (commonly caused by Trichophyton equinum)

Contributing factors to increased susceptibility:

  • Environment: warm, dark, crowded and moist conditions will lead to an increased chance of infection due to the ability of bacteria and fungi to proliferate in this type of environment.
  • Age: younger animals may be more susceptible to skin infections due to the immaturity of the immune system.
  • Degree of previous exposure and immunity which has developed.
  • Health status and body condition of the horse may reduce the ability to combat an infection or allow the entrance of external pathogens.
  • Photosensitivity: some skin diseases are photosensitive and will occur in areas of lighter coloured hair or skin.

Greasy Heel

Greasy heel, a common skin disease in horses, often occurs during the wetter months of the year where moisture and bacterial prevalence is rife. This particular condition is usually seen in the hind limb pasterns and is the result of a bacterial or fungal colonisation, often supported by continuous standing in wet, moist conditions (e.g. mud or a wet, unsanitary stable). The skin around the affected area becomes swollen, itchy and painful to touch and will often have a ‘greasy’ appearance due to abnormal secretions from within the sebaceous (fat secreting) glands. Skin quality may be affected if a dietary deficiency of zinc, biotin, Vitamin A (found in lush, green feeds), Vitamin E, or B-group vitamins exists.

Rain Scald/ Mud Fever

Rain scald or mud fever are common names for a condition known as Dermatophilosis, caused by the bacteria Dermatophilus congolensis which lives on the skin of carrier horses. D. congolensis needs a moist environment to thrive and reproduce, thus rain scald often occurs after rain in warm and humid climates. Infected horses have sores, lesions and scabbing usually concentrated on the rump, back, and legs. Carrier horses are prone to developing rain scald, but do not always show clinical signs, acting as a source of infection for other horses. Rain scald can be transmitted directly from horse to horse, or carried on items shared between horses, such as grooming tools, saddle cloths, and rugs.

Ring Worm

Is a fungal infection which presents on the surface of the skin, often causing noticeable changes in the hair and coat. Care should be taken when your horse has contracted ring worm, as it is highly contagious to other horses and humans. Due to the ease of transmission, case should be taken not to share tack, rugs, buckets or grooming kits which have been used on horses with ring worm.

Girth Itch

It is especially common in younger horses, often appearing in the girth region and can cause serious discomfort when trying to saddle a horse. This condition can be identified by bald, sore and inflamed areas of the skin, particularly around the girth region. Whilst it can be bacterial or fungal based, girth itch may be predisposed by poor skin quality (often the result of a vitamin and mineral deficiency), an ill-fitting girth, repeated exposure to wet and humid conditions.


Anhydrotic horses possess an inability to in response to hyperthermia. This impacts on the horses ability to maintain an appropriate body temperature of 38°C. “Dry coated” (anhydrotic) horses will often show a range of clinical signs including rapid breathing (tachypnea), poor exercise tolerance, dry skin, poor coat condition and hair loss, often on the facial region. Horses suffering from this condition may also show signs of inappetance, reduced exercise tolerance and may be more likely to “blow” after exercise in an attempt to expel body heat via the respiratory tract.


Common plants found in your horses paddock may trigger sunlight hypersensitivity, predisposing them for serious skin damage after sun exposure. Plants that cause photosensitivity include Alsike clover, St. John’s Wort, Bishop’s Weed, Spring Parsley, and Buckwheat. The toxins in these plants are not destroyed during the drying process and therefore hay may also cause a reaction. In some cases, signs of photosensitivity may not show up for several weeks after a horse has consumed the dangerous plant.

Primary photo sensitisation occurs when sunlight reacts with plant toxins circulating in the blood close to the skins surface. Secondary sensitisation is caused by ingestion of other plants, as well as some moulds and mycotoxins (fungi) that cause liver damage and thus increase the reaction of skin to sunlight. Some plants can cause both types of reactions. The symptoms associated with photosensitivity are very similar to that seen in mild sunburn, however in cases where exposure is prolonged, fluid discharge, scab formation, and skin tissue death can occur.


Sunburn can affect not only light coloured horses, but also white markings on dark coloured coats. It is most often seen in the early months of summer and spring when longer daylight hours coincide with shedding of winter coats. Redness, swelling, blistering, or peeling in severe cases can be seen on the skin around the muzzle, eyes, top of the tail and tips of the ears. Ensure adequate shade is provided in your horse’s paddock.

Ranvet’s White Healer

Ranvet’s White Healer is an astringent and germicidal ointment for use as an aid in the treatment of minor skin ailments and infections of horses. Ranvet White Healer has a four percent essential oil blend in a zinc cream base to provide a soothing cream with exceptional anti-microbial properties.

The blend of essential oils in Ranvet’s White Healer is effective against all three categories of infectious organisms, bacteria, fungi and viruses.  In laboratory tests at the concentration presented in Ranvet’s White Healer this blend of essential oils totally inhibits the growth of Dermatophilus congolensis the fungus-like bacterium responsible for Greasy Heel and Staphylococcus and Pseudomonas bacteria which may be associated with secondary infection of the pastern and heel. Ranvet’s White Healer can also be used for skin irritations, skin infections, cracked heels, and girth rash.

Treatment with Ranvet’s White Healer

  1. Contact your veterinarian to establish the predisposing cause and to determine treatment. It is generally advised to move the horse away from damp areas, keep hosing to a minimum and keep the horse’s legs dry.
  2. To clean any dirt or dried discharge from the affected area, wash with soap and water and pat dry, do not rub. To make certain the area is absolutely dry apply talcum powder and dust off. Apply Ranvet’s White Healer liberally to the affected area once or twice daily until the condition is resolved. It is generally not necessary to bandage.
  3. Consult your veterinarian if the condition does not improve; if pasterns are swollen and oozing or if your horse is lame.


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