Pastern dermatitis, mud fever, greasy heels, cracked heels and scratches are common terms used to describe a variety of inflammatory skin conditions affecting the lower legs, pasterns and heels of horses.
They are discussed here by Dr Chris Baldwin BVetMed(hons) MRCVS of Sussex Equine Hospital, based at Ashington, in our latest equine veterinary feature.
It is important to remember that they are terms describing a clinical symptom and are not a specific singular disease entity. For this reason, if your horse has this condition and it is not responding to your usual treatment always consult your vet for advice as it may be more involved than you think.
The group of clinical symptoms associated with mud fever include scabs, oozing, ulceration and hair loss at the back of the pasterns, heels and sometimes extending up the lower limb. It usually affects non-pigmented (white) legs worse than coloured skin.
Horses with a long history of the problem usually develop chronically thickened and folded skin at the back of the pasterns, which in turn, makes them more prone to redeveloping the condition.
The cause of the disease is often multi-factorial and is particularly associated with warm wet weather. The skin becomes broken and fragile either due to prolonged periods of being wet, or secondary to scratching due to leg mites, or any trauma to the skin such as from boot rubs or sharp vegetation.
This allows access for bacteria and the subsequent development of a skin infection. The most common bacterial involved is Dermatophilus which is the same bacteria that causes rain scald. However, some cases involve other bacteria and can also be associated with dermatophytosis (fungal infection). Other conditions that can cause identical symptoms are photosensitisation secondary to liver disease, pastern folliculitis, pastern leucocytoclastic vasculitis and eosinophilic dermatitis to name a few.
Treatment of mud fever depends entirely on the cause. If there is no immediate concern that one of the more serious conditions is involved, most horses are usually treated by trying to clean and dry out the affected areas. This usually involves stabling or moving out of the wet muddy environment, clipping the hair and removing the scabs and crust so that topical antibacterial, antifungal, antibiotic and anti-inflammatory treatments can effectively be applied to the area. Some horses may also require oral antibiotics in addition to oral anti-inflammatories such as steroids.
However, if your horse is not responding as expected to the treatment, further diagnosis may be required, this might involve your vet taking swabs for bacterial and fungal culture, blood tests to check for other more serious health issues and even biopsies of the affected area.
Ultimately if in any doubt call your own vet to organise a consultation to fully assess and discuss the nature of your horses’ condition as soon as possible.
Dr. C. Baldwin, BVetMed, MRCVS