Introduction: Why Skin Health Matters in Horses
The skin is the largest organ in the horse's body and serves as the primary barrier against infection, environmental damage, and fluid loss. Skin conditions are among the most common reasons owners seek veterinary advice across Europe, and they range from self-limiting minor infections to complex, potentially life-limiting conditions like sarcoids. This guide covers the most frequently encountered equine skin problems, with practical advice on identification, EU-licensed treatments, and prevention strategies.
Rain Scald (Dermatophilus congolensis)
Rain scald — also called rain rot or streptothricosis — is caused by the bacterium Dermatophilus congolensis, which thrives in wet conditions. It is particularly prevalent in the UK, Ireland, and northern France during wet autumn and winter months but can occur anywhere horses are exposed to prolonged moisture.
The condition presents as matted tufts of hair with crusts beneath that, when removed, reveal moist, pink skin lesions. Lesions typically appear along the back, rump, and neck — areas exposed to rain. In mild cases, simply improving shelter access and keeping the skin dry may be sufficient. More established cases benefit from softening and removing the crusts (using dilute Hibiscrub — chlorhexidine gluconate solution) and applying topical antibacterial washes. Severe or spreading cases require veterinary assessment and may need systemic antibiotics. Hibiscrub is widely available across Europe and is an effective first-line wash for superficial bacterial skin infections in horses.
Mud Fever / Pastern Dermatitis
Mud fever is a form of pastern dermatitis most commonly caused by Dermatophilus congolensis, though Staphylococcus species, dermatophyte fungi, and chorioptic mites can also contribute. It affects the lower limbs, particularly around the heels, pastern, and fetlock, and is strongly associated with wet, muddy conditions and repeated wetting and drying of the skin.
Signs include crusty scabs over the heel and pastern, heat and swelling, lameness in more severe cases, and raw or weeping skin when crusts are removed. Management involves removing the horse from mud where possible, keeping the limbs clean and dry, gently removing softened crusts, and applying antibacterial washes or barrier creams. Zinc oxide-based barrier creams are widely used as a protective layer on clean, dry skin to prevent moisture ingress. Horses with white legs or pink skin are particularly susceptible. Chronic or refractory cases require veterinary investigation to identify any underlying contributing factors such as mite infestation or fungal infection.
Ringworm (Dermatophytosis)
Despite its name, ringworm is not caused by a worm but by dermatophyte fungi, most commonly Trichophyton equinum or Trichophyton mentagrophytes in horses. It is highly contagious between horses and can also be transmitted to humans (zoonosis), making prompt management important.
Ringworm presents as circular or irregular patches of hair loss with scaling, often initially appearing around the girth, saddle area, neck, and face — areas of tack contact. The lesions are not usually itchy unless secondary bacterial infection occurs. Diagnosis can be confirmed via fungal culture or microscopy of hair samples.
Imaverol (containing Enilconazole) is an EU-licensed antifungal wash specifically indicated for the treatment of ringworm in horses. It is diluted and applied as a wash or spray to affected areas on multiple occasions over a two-week period, following the product label directions. All grooming equipment, rugs, and tack that have been in contact with the infected horse should be disinfected, as fungal spores are highly environmentally persistent. Malaseb shampoo (containing Miconazole and Chlorhexidine) is another option used by vets in some EU countries for fungal skin infections.
Sarcoids
Equine sarcoids are the most common skin tumour in horses, accounting for the majority of equine skin neoplasia cases seen across Europe. They are caused by bovine papillomavirus (BPV-1 and BPV-2) and can occur as several distinct clinical types: flat (occult), verrucous (warty), nodular, fibroblastic, mixed, and the aggressive malevolent type. They most commonly appear on the face, around the eyes, on the sheath, lower limbs, and abdomen.
Sarcoids are locally invasive and do not metastasise (spread to distant organs), but they can grow rapidly, ulcerate, and cause significant welfare problems depending on their location and size. They are notoriously difficult to treat and have a high recurrence rate regardless of the method used.
Available treatment options in the EU include:
- Liverpool Cream (Cisplatin-based) — a chemotherapy cream applied topically under veterinary supervision. It is one of the most commonly used treatments for accessible sarcoids across the UK and Europe and has good reported success rates in eligible lesion types.
- Immunotherapy — including BCG (Bacillus Calmette-Guerin) injections into the tumour, which stimulate a local immune response. Particularly used for periocular sarcoids.
- Surgical removal — carries a high recurrence risk if used alone and is best combined with another modality.
- Cryotherapy — freezing with liquid nitrogen, effective for small flat or nodular lesions.
- Laser therapy — available at specialist referral centres across Europe.
Do not attempt to interfere with, clip, or biopsy a sarcoid without veterinary guidance, as trauma can trigger rapid and aggressive growth. Seek specialist equine dermatology or oncology advice for any lesion you suspect may be a sarcoid.
Melanoma in Grey Horses
Grey horses have a significantly elevated lifetime risk of developing melanomas — pigmented skin tumours that arise from melanocytes. Estimates suggest that up to 80 per cent of grey horses over the age of fifteen will develop melanomas. These most commonly appear under the tail, around the perineum, on the sheath, and on the face around the lips and eyelids.
Most equine melanomas are benign and slow-growing, but they can become locally invasive or, in a minority of cases, undergo malignant transformation and spread internally. Regular monitoring is essential — note the size, number, and texture of lesions and report any changes to your vet promptly.
Management is often conservative (watchful waiting) for slow-growing, non-obstructive lesions. Surgical removal is considered for lesions in problematic locations or those showing rapid growth. Cimetidine (an H2-receptor antagonist) has been used anecdotally in some countries with limited evidence of benefit. Research into immunotherapy and other treatment options for equine melanoma is ongoing across European veterinary institutions.
Prevention and Barrier Care
Many common equine skin conditions are preventable or manageable with good husbandry practices. Key preventive measures include:
- Providing adequate shelter from rain and mud to reduce the risk of rain scald and mud fever
- Implementing strict biosecurity protocols when introducing new horses — quarantine periods and checking for ringworm lesions
- Regularly disinfecting shared grooming equipment, rugs, and tack
- Using barrier creams on susceptible lower limbs during wet weather
- Conducting regular skin checks as part of daily grooming, particularly under rugs and tack contact areas
- Scheduling routine veterinary and farriery checks so early skin changes are not missed
When in doubt about any skin lesion — whether it is spreading, changing, bleeding, or in a sensitive location — always seek veterinary advice rather than attempting home treatment. Early, accurate diagnosis is the most effective tool in managing equine skin disease.