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Wet weather woes

Given the recent wet conditions, an increase in greasy heel, rain scald, and similar conditions should come as no surprise, writes RACHEL ROAN.

Recent wet weather in Australia, particularly in the eastern states, has created the perfect conditions for greasy heal, rain scald and other similar scabby skin conditions. Broadly speaking, these ailments are a form of dermatitis; an infection of the dermis (the top layer of the skin). Reassuringly, equine veterinarian Dr Calum Paltridge says that although these ailments are common, they often aren’t serious and the treatment is straightforward.

Greasy heel

Greasy heel presents with a build-up of thick, crusty scabs on the pasterns

Greasy heel, also known as mud fever, is commonly caused by bacteria, mites, allergens, or a fungal infection. While the cause may vary, the condition presents with the same build-up of thick, crusty, and painful scabs on the pasterns. Horses with white socks and pink skin pigment are predisposed to infection, as are horses who have spent time in wet or humid conditions. “These conditions weaken the defence barriers of the skin, allowing entry to pathogens,” Calum explains. “For the most part, the cause is normal skin bacteria or bacteria from the environment, which can easily get past the defence barriers if the skin is continuously wet, cracked, or damaged. Once it’s in, it starts an infection in the skin.”

Antiseptic scrubs and washes, antiseptic and anti-inflammatory creams, or other topical treatments such as Prednoderm – which contains a mix of steroids and antibiotics – are on the list of treatment options. Calum says that in most cases, topical treatments are sufficient, and in healthy horses, greasy heel (and other forms of equine dermatitis) is usually self-limiting. However, there is potential for the condition to turn into cellulitis, a more serious infection. Unlike dermatitis, which is only skin deep, cellulitis is an infection of the soft connective tissue structures in the legs. Calum advises that best practice is to treat severe greasy heel in order to reduce the chance of it developing into cellulitis. “If it turns into a secondary infection like cellulitis, it will need a more intense treatment. In severe cases, the horse will need to go on systemic antibiotics to treat the infection, and bute to reduce pain and inflammation,” he adds.

To successfully treat greasy heel, removing your horse from muddy, wet conditions is crucial. Without stabling, or at least somewhere to keep your horse dry for a sustained period of time while the condition clears up, it is difficult to completely rid them of the infection and treatment time will be prolonged. “When it’s continuously wet, it doesn’t matter how good your management is. Greasy heel is very difficult to treat if horses are standing in mud for a large part of the day, for weeks on end,” Calum tells me.

In his experience, greasy heel seems to be more painful than rain scald, and ensuring you don’t get kicked while treating your horse can be a challenge. It’s important to recognise that even the quietest horse can become irritable and lash out, so approaching with care is strongly advised. “Scabs, pus discharge, hair loss, and a red, inflamed appearance are all signs of greasy heel,” Calum explains, and with this thick, scabby build-up, it’s difficult for topical treatments to reach the root cause unless the scabs are removed, which is painful but necessary.

In some cases, greasy heel can also cause swelling in the joints beneath the infected area, and your horse can show signs of tenderness or lameness in the affected legs. “If they get greasy heel over a moveable area like the back of a fetlock, it can be quite painful when their joints are moving and pulling at the skin.”

For advanced cases of greasy heel, Calum suggests the safest approach is for your vet to sedate your horse, so the affected area can be clipped back and thoroughly cleaned before continuing with the treatment. “Once sedated, we aim to remove the scabs and affected tissue to get it back to healthier tissue. Scab removal can often cause bleeding if it’s severe, so it may be kinder to do it over a couple of sessions instead of all at once.” By removing the scabs, cleaning the area with a solution to kill the bacteria, and opening it up to the air, you can target the infection directly and hopefully reduce healing time.

Rain scald

Rain scald affects a horse along their back, neck, and head.

Rain scald is an easily identifiable type of dermatitis that affects a horse along their back, neck, and head. “Rain scald presents as chunks of hair coming off with scabs and pus underneath it,” Calum says. “It typically occurs where the saddle sits and it can cover quite large areas.” A horse suffering from rain scald will usually be too uncomfortable to be ridden if the saddle area is affected. To avoid exacerbating the problem, Calum’s advice is to treat the condition before attempting to ride your horse again.

A wet, humid environment creates the ideal conditions for rain scald to develop, and like most things, prevention is better than cure. During wet weather, it’s worth investing in a good quality, waterproof rug to help protect your horse. “If you have a cheap or poor quality rug that isn’t waterproof, and your horse is sitting there with a wet rug on, that will definitely predispose them to rain scald,” Calum tells me. “It’s the wet rug combined with the horse’s body heat that causes the problem.”

Similarly, leaving your horse to sweat on a warm day under a synthetic or canvas rug can also cause rain scald. I ask if washing your horse and rugging them before they’re dry would have the same effect: “Definitely. If you work your horse until it’s sweaty, wash it down and don’t thoroughly dry it before throwing a rug back on, they’ll be back in the paddock with a wet, humid environment on their back,” Calum says. “Most synthetic rugs don’t breathe well – they can be great if they’re waterproof and your horse is dry, but if the horse is damp before you rug, it can really trap the moisture.”

While rugging helps reduce the risk of developing rain scald, if your horse already has the condition it’s important to let the area breath. Unless they are being kept dry under a cotton rug, rugging can actually increase the severity of the symptoms. In Calum’s experience, rain scald will heal best if the coat is clipped, exposed to air and sunlight, and allowed to dry out. Similar to greasy heel, topical treatments can improve the symptoms.

If your horse has rain scald it’s important to let the area breath (Images by Paula Campion).

Change in the weather

In most cases, dry, cold weather will improve cases of greasy heel and rain scald. “If the weather dries out, a healthy horse will usually come good without treatment,” Calum explains. “Treatment can definitely speed the healing process and reduce the level and length of discomfort your horse endures, but for the most part, if you leave it alone it will usually sort itself out.”

On a final note, it’s important to distinguish between rain scald and Queensland Itch, which are sometimes confused. Rather than a form of dermatitis, Queensland Itch is a hypersensitive reaction to insect bites, which causes an allergic reaction followed by intense itching. “They drive themselves mad scratching,” Calum says. “Although rugging can help prevent this, it’s really hard to deal with in areas along the coast. The only solution is to avoid contact with insects by moving the horse further inland to colder climates,” he adds.

Dr. Calum Paltridge (BVSc (Hons) MANZCVS) is the owner and veterinarian at Thunderbolt Equine Veterinary Services in Armidale, NSW.