ridecamp@endurance.net: [endurance] "Mud Fever"
[endurance] "Mud Fever"
Patricia Dowling DVM (dowling@sask.usask.ca)
Tue, 03 Oct 1995 14:54:38 -0700 (PDT)
Mud fever (aka scratches, grease heel, rainrot, rain scald)
is caused by Dermatophilous congolensis - a gram positive,
facultative anaerobic actinomycete (easiest to think of it
as a higher bacteria - not quite a fungus). It is part of
the normal flora on horse skin, and does not cause problems
until the skin is damaged and moisture is present. Moisture
then causes the bacteria to release motile zoospores that
invade damaged skin and initiates the characteristic skin
lesions. Treatment guidelines:
1) many cases spontaneously cure if the area can be kept dry
2) keeping the skin dry is very important
3) crust removal and topical therapy is very useful. I've
had good success with nitrofurazone ointment alone or in
combination with corticosteroids for swollen, painful
lesions. On legs, it speeds up recovery to keep the affected
areas covered to provide a continuous contact of the
ointment and to keep the lesions dry.
4) systemic treatment may be necessary in severe cases.
Since this is a higher bacteria, it will respond to
antibiotics. Penicillin is recommended in most texts, but
for those who don't like injecting their horses, in my
clinical experience, Trimethoprim/sulfas are equally
effective.
Some horses are far more prone to flare ups than others. One
can keep lubricating things on the pasterns to prevent
chapping and cracking of the skin from wet pastures -
vaseline, mineral oil, etc work well. Avoid washing muddly
legs - brush dry instead.
Trisha Dowling, DVM, MS, Dip ACVIM,ACVCP
Associate Professor, Veterinary Clinical Pharmacology
Western College of Veterinary Medicine