Inflammatory conditions of the pastern will be appearing with increasing frequency during the summer season. But as a diagnosis, “pastern dermatitis” leaves much to be desired. When this alone is noted on a biopsy report, it leaves the clinician and client with little useful knowledge.

Causes of Inflammatory Conditions of the Pastern


  • Dermatophilus congolensis
  • Staphylococcus aureus
  • Spirochetosis
  • Any cause of pyoderma


  • Pythium spp.
  • Malassezia spp.
  • Phaeohyphomycosis
  • Zygomycosis


  • Chorioptes mites
  • Pelodera strongyloides
  • Strongyloides westeri

Non-infectious causes

  • Contact irritant
  • Hypersensitivity
  • Drug reaction
  • Trauma
  • Photosensitization
  • Pastern leukocytoclastic vasculitis
  • Photoaggravated vasculitis
  • Pemphigus foliaceus
  • Chronic progressive lymphedema


Other names for this condition, with slightly varying clinical appearances, include scratches, mud fever, grease heel, dew poisoning, grapes, canker, and verrucous pododermatitis. But again, these colorful descriptors do not indicate the root of the problem. For that, pathologists rely on a series of modifiers describing the more subtle histologic (microscopic) variations on the theme of “dermatitis,” and, jus