What the Muck Is That? Winter Skin Diseases

Prepare for phantom itching.

Each week we investigate one equestrian conundrum in “What the muck is that?” This week we take a look at winter skin diseases including ringworm, lice, and mites.


Ringworm is a fungal infection of the skin and hair, occurring more often in the fall and winter when horses are kept indoors away from fresh air and sunlight.

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What to look for:

  • Hives that develop into scaly, crusty, round areas of hair loss
  • Not usually itchy or painful.
  • Most common in areas under the saddle or girth as well as on the face and neck.

How to treat it:

  • Quarantine
  • Daily bathing
  • Sanitizing equipment, stalls and other things the infected horse may have come in contact with.
  • Diluted solutions of chlorhexidine, povidone iodine, lime sulfur and bleach are commonly used.

Lice are tiny insects that spend their entire life cycle on the host. They thrive in cold weather when hair is long.

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What to look for:

  • Using a magnifying glass, look for lice in the horse’s mane.
  • The lice will be on the skin between the hairs.
  • The hair will pull out easily where lice have been feeding.
  • Often there is greasy skin and heavy dandruff.

How to treat it:

  • Apply lice spray or dust.
  • Two weeks later, repeat the process.
  • Brushes, blankets, and tack used on the infested horse also should be treated.

Mites are tiny parasites active during cold, wet weather.


What to look for:

  • Skin inflammation
  • Dandruff
  • Hair loss
  • Pustules or Bloody Crusts
  • Nodules that feel like birdshot
  • Leg mange

How to treat it:

  • Veterinarian examination to take skin scrapings and observe under a microscope for diagnosis.
  • Mites can be eliminated with sprays and insecticides, but treatment is dependent on the type of mite.
  • Affected horses should be isolated.

Go Riding!


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