Grease Heel in Horses

Grease heel is a condition that affects horses by causing inflammation, scabbing, and cracked skin around the lower legs and heels. Most commonly seen in the spring and fall, grease heel typically develops when horses stand in muddy or wet conditions that harbor bacteria. This leads to dry skin that eventually becomes cracked, then emits a thick fluid that can appear greasy. Any breed of horse can develop grease heel in wet weather, but those that spend time in dewy pastures or areas that stay damp are at higher risk (making regular stall maintenance especially important during rainy seasons). Horses that are more prone to sunburns or solar dermatitis, like those with white socks or pasterns, may also be more likely to develop greasy heel. Grease heel is unsightly, and while it's not immediately dangerous, it can cause your horse to become lame and risk serious infections if left untreated. When this condition is caught early, persistent home treatment can be effective.

What Is Grease Heel?

Grease heel is a type of dermatitis caused by bacteria that leads to inflammation on the skin of horses, typically affecting the heels or lower legs after the horse is exposed to wet weather conditions. Since its common names tend to be regional, horse owners may also hear this condition referred to as dermatitis verrucosa, seborrheic dermatitis, mud fever, scratches, dew poisoning, or greasy heel. Grease heel may begin low on the horse's body and concentrated around the heels, but it can also spread up the legs to affect the cannon area.

Symptoms of Grease Heel in Horses

Grease heel appears on the lower legs as patches of scurf beneath the hair. Your horse will experience itchiness and irritation, and the following symptoms may present as well:

Itchiness and Irritation

The hair itself will start to look thin or matted. Under the scurf, the skin will be itchy and irritated. If the grease heel is mild, it may only look dry and have dandruff. It may not be as obvious on horses with a lot of feathering on their lower legs. 

Cracked, Red Skin

When greasy heel isn't caught early, the skin on your horse's heels will become more inflamed and cracked. Cracked skin in the lower legs can be difficult to heal since the area is always flexing as the horse walks. The pain from the inflamed skin can cause the horse to appear lame.

Discharge From Affected Areas

As the condition progresses, a thick, mucous-like fluid will begin to emit from the affected area. This symptom is how the name "grease heel" was coined, as it can appear greasy over irritated skin. The lesions may become crusty as the fluid dries onto the affected areas.

Granulomas

Left untreated, the skin can become deeply cracked and eventually infected. Granulomas may develop in more serious cases. This type of scar tissue and equine cellulitis consists of inflammation in the deeper layers of skin, resulting in heat and swelling in the legs.

Causes of Grease Heel

The same conditions that cause rain scald also cause grease heel: microbes that thrive in mud and wet areas. Grease heel is typically caused by the same bacteria that's seen in rain scald cases, but if it's left untreated, other bacteria can also infect your horse. The following are common causes of grease heel:

• Muddy outdoor conditions: If pastures and paddocks are muddy, it may be hard to provide a place where the horse’s hoofs and legs aren’t wet. When the horse’s legs are constantly damp, the microbes that cause grease heel can thrive. Grease heel may be more prevalent in the spring when pastures are muddy from snowmelt and rain, and again in the fall when the weather is wet.
• Damp stalls: Damp stalls are especially a risk if ammonia from urine builds up, which can cause and exacerbate grease heel.
• Sun exposure: Horses with white legs and pink skin are more likely to be bothered by grease heel than darker-skinned horses. Sunburns irritate the skin, which makes it easier for this condition to develop.
• Living conditions: Leg boots can contribute to the buildup of sweat, which allows bacteria to develop in the damp area. It's essential for horse owners to fit leg boots properly and clean them thoroughly. t

Diagnosing Grease Heel in Horses

If you suspect that your horse may be developing grease heel, schedule a veterinary appointment as soon as possible to properly diagnose the affected area and begin treatment. Your vet will likely examine the horse and determine whether its living conditions are the cause of the problem. If they know your horse's history, your vet may be able to complete the diagnosis with a simple examination, but they may also test for bacteria. These tests typically consist of an acetate tape impression or samples from the horse's hair that can be examined under a microscope.

Treatment

Mild grease heel can be treated at home by brushing away any dirt and dead hair, washing the affected area with antiseptic or anti-fungal soap, and working a topical through the hair onto the skin (like an antiseptic cream or zinc oxide paste). Some horse owners claim that creams designed to treat yeast infections are effective, but zinc oxide creams and lotions are also a great option. Look for diaper creams such as Ihle’s Paste or Desitin with a high quantity of zinc oxide. Keep the area clean and dry, and continue treating it until the condition is gone.

If the grease heel is severe, owners may need to wrap the area to prevent dirt from sticking to the cream. However, wraps and bandages can hold in moisture, so they should be replaced often with the horse's skin dried thoroughly between uses. Your veterinarian might recommend using a drying spray like Cetrigen each day to keep moisture at bay until the area heals fully.

If the grease heel covers a large area, has become badly cracked or there is any evidence of swelling or infection, call your veterinarian. Granulomas caused by grease heel can be removed by a veterinarian.

Any brushes or equipment used on a horse with grease heel should be sterilized before use on another horse. It may be helpful to keep a separate set of brushes for each horse being treated to prevent cross-contamination. Wash your hands after treating your horse to avoid spreading grease heel and other skin conditions to others.

Prognosis for Horses With Grease Heel

In most cases, grease heel can be treated with simple at-home care steps by owners. Most horses affected by this condition should make full recoveries once the bacteria is successfully removed. Horses should be stabled during treatment to prevent any new bacteria from developing and for owners to closely observe the treatment process, making any adjustments as necessary. Once your horse has recovered, preventative care is important to avoid future infections.

How to Prevent Grease Heel

Grease heel may appear to disappear or be slightly better during dry weather, but it can flare up quickly when the weather turns damp again. Thankfully, owners can utilize a few simple prevention methods:

Maintain Proper Living Conditions

Keep your horse in clean, dry conditions. Clean the stalls and don’t allow dampness or ammonia from urine to build up. Keep paddocks and pastures free of manure build-up, and improve drainage if mud becomes a problem. Avoid turning horses out in dewy pastures when grease heel is a high risk.

Groom Frequently

Frequent grooming can remove the dirt and dander that give the microbes a home. Wash your horse’s legs down after exercise to remove sweat, and ensure they are always dried thoroughly. During wet weather, owners can also apply creams like Sudocrem to the lower legs to waterproof these areas (though care should be taken to wash and dry the legs first; otherwise, bacteria may be trapped inside).

Use Sunscreen on At-Risk Horses

If your horse has white socks or pasterns, an especially helpful prevention method is to apply sunscreen to these white areas on a regular basis. A thin coating can be used every one to two days.