This isn’t an exclusive treatise on this issue, but
hope this helps some…
WHAT IT IS: a Dermatitis
NAMES: Scratches, mud fever, mud rash, cracked heels, dew
poisoning. If it has an exudate (its weeping), its called Grease Heel.
PATHOPHYSIOLOGY: Infectious, or non-infectious disorders
that result in inflammation, ulceration, crusting, or grape-like skin (in
long-standing cases).
SOME CAUSES: it is a Syndrome, which means its causes are
multifactorial (as opposed to a specific diagnosis where theres 1 cause in all
horses).
Physical Irritants (most common
cause)
Chemical Irritants (ex: “soring”
in gaited horses)
Contact Allergy
Contact Photosensitization
Dermatophytes (chiggers, flies,
ticks, mites etc)
Immune system disorders
BREEDS/HORSES PREDISPOSED: Drafts (from their fetlock
feathers), Arabs (in sandy soil), white skin at the pastern area.
AN EXAMPLE OF HOW IT GETS STARTED: Anything that can cause a
break in the skin. Ex: horse is bitten by flies leaving minute openings in the
skin. Then, due to the normal un-sterile conditions of a pasture or stall,
bacteria get in the minute wound openings, setting up a bacterial infection.
Since the bacteria didn’t cause the primary inciting incident (in this
case, the biting flies did), their contribution to this cycle, is referred to
as a secondary bacterial infection.
FOCUS OF TREATMENT: determine & treat the underlying
cause(s), & keep the area dry & clean (for ex: wait until the pasture
morning dew is gone before letting the horse out).
