Veterinary advice should be sought before applying any treatment or vaccine.


Pastern Dermatitis, Mud Fever, Mud Rash, Cracked Heels, Dew Poisoning, Greasy Heel, Bacterial Dermatitis

Pastern dermatitis is a collective term for an intractable, painful, exudative dermatitis affecting the back of the hose's pasterns. It is most frequently found on the non-pigmented (white-skinned) areas.
Where to look for scratches on horses
There are three different forms of pastern dermatitis with the mildest form the most common.
  • Mild form: Matted hair, minor swelling, scaling and crusting of skin
  • Exudative: Skin redness, skin erosion, hair loss, serous to purulent crusting of skin, vasculitis
  • Chronic Form: excessive granulation tissue (fibroblastic proliferation) that becomes cornified, nodular proliferations of hyperkeratosis and lichenification, painful lesions, lameness


Hard, crusty lesions
When pulled away, hair pulls with it
Variable itching
Oozing serum or blood
Painful to the horse


  • History
  • Clinical signs
  • Physical exam
  • Skin surface cytology
  • Skin scrapings
  • Dermatophyte culture



Avoid turning horse out before the morning dew has dried
Keep horse's legs clean and dry during wet weather conditions
Avoid turning horse out in muddy, wet, or sandy pastures
Keep lower leg hairs short by periodically clipping
Topical Therapies
Scrub legs with antibacterial shampoo (active ingredients include benzoyl peroxide (3%), chlorhexidine (2%) and ethyl lactate), applied daily for 7 to 10 days, then 2 to 3 times weekly.
Apply zinc oxide between wash sessions to help soften.
Do not pull scabs.


  • Changing the horse's turnout schedule so that they aren't outside during dew formation in the early morning
  • Regularly drying off legs with a towel after baths
  • Maintaining pastures so that grass is not excessively long and/or any photosensitivity causing weeds are not present
  • Minimizing prolonged exposure to muddy conditions or wet bedding
  • Keep lower leg hairs short by clipping


Scientific Research

General Overviews

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Risk Factors

  • Long, thick hair (feathering) on their lower legs
  • Frequently standing in muddy pastures or wet bedding
  • Exposure to certain irritant plants in the pasture
  • Exposed to frequent wet environments
  • Turned out in pastures with long grass in the early mornings, when dew forms.
  • Recent trauma to lower limbs