Mud fever, or pastern dermatitis, is a skin condition caused by a variety of bacteria which thrive in muddy, wet conditions.  The infection activates when the surface of the skin becomes damaged in some way eg by prolonged exposure to muddy, wet conditions. 

Could any horse get mud fever?

Many horses who live out in muddy fields never develop mud fever.  Therefore, why are some horses more susceptible to the condition than others?

Traditionally mud fever was blamed on a specific bacteria (Dermatophilus congolensis) however it is now recognised that many different factors can contribute to a horse developing symptoms of mud fever.  The outer epidermal layer of the skin acts as a physical barrier to the environment.  Therefore, any damage to this layer of skin can result in bacteria entering which can then cause an inflammatory reaction and potential infection.  The outer layer of the skin can be compromised for a variety of reasons eg mite infestation, incorrect usage of bandages/boots, wet and muddy conditions, constant washing of the legs, pastures with rough vegetation, lots of work in sandy arenas, certain soils and bedding.  It is also important to recognise that when a horse has a compromised immune system eg as a result of a disease such as Cushings, this will make them more susceptible to bacterial infections.

Does my horse have mud fever?

Initially, you may notice the skin at the back of the horse’s pastern becoming inflamed before spreading around and up the leg. The lesions will usually only go as far as the fetlock but in extreme cases the cannon can be affected as far as the knee or hock. In the beginning, there may be some hair loss and crusting but as the infection progresses, it becomes more pronounced within the horizontal skin folds. The lesions may produce a discharge which will dry forming thick crusts that harbor the bacteria within. In more severe cases, you may notice a swollen and hot lower limb.  It will progress to being very painful and therefore you may notice signs of lameness in your horse.

 

 

 

How is mud fever diagnosed?

If you notice that your horse has symptoms of mud fever, it is important your vet is called so that they can take a full history and undertake a thorough examination.  As mud fever can have a number of causes, the vet may wish to take hair samples, swab the area and/or take a skin scrape.  This can check for fungal or bacterial infections as well as for parasites such as mites. If the mud fever is not responding to treatment, a skin biopsy may be recommended.

 How can I prevent my horse from getting mud fever?

It’s important to try and prevent your paddock from getting badly churned up, as the bacteria are transmitted in the soil. If possible, periodically changing the place at which you enter the field and moving any water troughs can prevent one area of ground getting very damaged. If appropriate, you could also consider covering particularly muddy areas with straw or sand.  It is also much safer to allow your horse’s legs to dry naturally and then brush off the mud rather than washing them on a daily basis.

Prevention is better than cure however monitoring your horse closely and checking their legs on a daily basis should mean that any symptoms are noticed early.  This allows for an early diagnosis and treatment which should clear up any minor infection quickly.

 

How can I treat my horse for mud fever?

Treatment varies depending on the cause and severity of the mud fever.  There are a number of treatments available all with the aim of treating the underlying cause and allowing the skin’s natural barrier to heal.

Your vet would likely have prescribed or recommended an anti-bacterial barrier cream to use which is most suited to your horse.  This will need to be applied once your horse’s legs are clean and dry. Remember: always test a small patch of skin with the cream for 24 hours first to check your horse does not have an allergic reaction to any of the ingredients.In all cases it is very important to try and keep your horse’s legs as dry as possible. However you will need to wash the affected leg(s) with a warm, very dilute Hibiscrub solution – 0.1% solution is recommended – and rinse it off fully with warm, clean water. Never use cold water and do not apply neat hibiscrub to your horse’s skin.  The leg will need to be dried thoroughly (ideally a clean towel for each leg so as not to spread the infection around).  If you usually keep your horse’s feathers long, you may want to consider clipping them whilst the mud fever is treated.  As washing and drying the leg damages the skin, it is recommended this is only done every 4 days or so.  This will however depend on whether you are stabling your horse during the process or still turning them out.

Removing the scabs can be a controversial area therefore follow the recommendations of your own vet with regard to this.  In most cases, it is recommended that you remove any scabs which fall away easily but do not force the issue. 

If you are able to stable your horse then this is likely to reduce the healing time.  This is due to the fact you are removing them from the contaminated mud and also stopping the wet-dry cycle which damages the skin.

Other treatments such as antibiotics and pain relief/anti-inflammatories may be prescribed by your vet.

 

Key points for the successful management of mud fever

• Check your horse’s legs daily to monitor for any signs of mud fever.

• Do not wash your horse’s legs too often and keep them as dry as possible.

• If your horse has long feathers, consider clipping them.

• Stable your horse where possible while treating.

• Rotate and rest paddocks, change entry points and move water troughs to prevent particularly muddy areas developing.

• Make sure you use a warm dilute (0.1%) Hibiscrub solution to wash the affected area, rinse it fully with warm, clean water and dry it thoroughly

• Remove any scabs which fall away easily.

• Use a recommended barrier cream as advised.

• Always seek the advice from your vet!