08/11/2025
** Mud Fever: Washing legs as a treatment for mud fever does more harm than good in most cases unless you have a solarium or a horse that loves hairdryers**
Last week I read 127 comments about how to treat mud fever, 114 of which recommended washing and scrubbing legs twice a day for 7-14 days with various fancy lotions and potions. This advice worries me a lot, since without the proper aftercare (ability to totally dry the area and keep it dry), washing will contribute to the persistence and potential worsening of mud fever if the wet-dry cycle is not broken effectively.
Horseās skin is made up of several complex structures which can be categorized simply into the outer epidermis and the inner dermis. Under normal healthy circumstances, the epidermis is thin, yet tough and able to protect the horse against the external environment, however with extremes in environmental conditions (e.g. increase in moisture), injuries (e.g. scratches) and external parasites (e.g. mites) the epidermis can be weakened and allow a wide range of microorganisms (e.g. bacteria and fungi) which normally co-exist, harmlessly on the skin (commensal skin flora), or in the the environment to pe*****te to the layers below resulting in mud fever (if on the legs), or rain scald (if on the body).
Wet ground conditions are the number one cause of mud fever (not the mud per se), whilst humid conditions are the number one cause of rain scald (you don't need rain for rain scald to occur). The key to resolving both is to stop the wet-dry cycle from continuing. In the case of mud fever, washing affected legs will keep the wet-dry cycle going and every time the legs are washed without effective drying (towel drying is not enough) the epidermis is prevented from healing and or damaged further. Excessive leg washing can even cause mud fever to occur in the first place. Some of the photos I saw posted this week were clear examples of where horses legs have been repeatedly washed and the ātreatmentā has made the situation considerably worse. What happens then is people will resort to filling up a bucket of warm water with diluted (or worse, neat) hibiscrub (or similar) and then throw it down the legs since the mud fever has become so painful.
Rather than washing the legs which maintains the wet-dry cycle, the most effective method is to massage antimicrobial barrier creams into the affected area twice a day with two aims in mind; firstly to soften the scabs to encourage them to fall off (if you massage for only a few minutes the scabs will begin to soften), and secondly to provide a waterproof barrier until the epidermis heals. This process should be repeated until all the scabs have come away and the skin beneath heals. If the mud fever was triggered by mite bites or associated scratching, then anti parasitic treatments should be used alongside the barrier cream. Remember that the microorganisms which cause mud fever are found naturally on your horsesā skin and within the surrounding environment and therefore the only way to resolve mud fever is to use methods which allow the skin to repair its natural protective layer and which break the wet-dry cycle.
If you have been battling what seems a never ending war and you are sure the wet-dry cycle has been broken yet the area is still not healing, your horse might have rare a condition called leucocytoclastic vasculitis which is an immune dysfunction which presents just like mud fever. This condition exclusively affects white legs and will need steroids to resolve.
Photo credit: Jo Fairbrother
