What is mud fever?
Mud fever is a bacterial condition which typically affects the lower legs of horses. It is also known by several other names, including pastern dermatitis, greasy heels and cracked heels.
The bacteria most commonly involved is called Dermatophilus congolensis, which is common in wet environments. However, it is now known that other bacteria, such as Staphylococcus and pseudomonas species, as well as mites and fungi can cause the condition.
On normal healthy skin “commensal’ microorganisms will be living without causing an issue. However, when the skin is compromised and damaged, such as after being wet for a long time, the outer epidermal layer will no longer be able to protect the layers beneath, allowing for bacteria to cause an infection and inflammatory reaction.
What causes mud fever?
There are many things that can damage the outer layer of the skin and cause a horse to develop mud fever:
- Prolonged damp, mild conditions
- Standing in deep mud
- Broken or damaged skin
- Skin conditions including chorioptes mites, fungal infections, photosensitisation and autoimmune disorders
- White limbs are often more commonly affected
- Regular washing of limbs without drying them afterwards
- Excessive sweating under tack or rugs
What are the clinical signs?
- Crusty scabs with ulcerated, moist lesions beneath
- Matted hair, or loss of hair with raw skin beneath
- Creamy white, yellow or green discharge between the skin and scab
- Occasionally deep fissures within the skin
- Heat, pain and swelling
- It may possibly be associated with lameness
- In very severe cases, the horse may be lethargic or depressed
- Mud fever can occur in other areas of the body, such as on the back where it is called rain scald
Treatment
- Keep the skin clean and dry
- Gently remove scabs to allow treatment of the affected areas
- Clip the leg to help get on top of the infection and to reduce the scabs
- Clean the area with a mild disinfectant such as dilute Hibiscrub or iodine, then rinsed with water before thoroughly drying
- Apply stable bandages to dry legs to provide support and reduce lower limb swelling
- Most veterinary practices can provide creams with anti-inflammatory and antibiotic properties which are very effective
- Individual treatment for underlying causes such as mites or fungal infection may be required
How to prevent mud fever
- For horses who are particularly prone, you may need to completely avoid turnout in muddy conditions
- Good paddock management – rotate fields to reduce poaching and put hardcore down in places where horses congregate, such as gateways and water troughs. Fence off particularly muddy areas
- Regular grooming with a soft bristled brush to remove mud
- If it is necessary to wash your horses legs, ensure that they are dried thoroughly afterwards
- Apply barrier creams which create a layer between your horse’s legs and the mud.
- Daily inspection of your horse’s legs to pick up small problems as early as possible
There are also specialised mud boots available, however these must be fitted correctly to avoid rubs and sores which may cause more of a problem.