Pathergy, Pathergy Reaction, Pathergy Test

  • Definition
  1. Pustule, Blister or ulceration in response to minor Skin Trauma
  • Technique
  1. Pustule or ulceration forms within 24-48 hours in response to minor Skin Trauma (e.g. SQ Injection)
  2. Minor induced Skin Injury
    1. Subcutaneous saline injection (small volume) or
    2. Skin prick with small gauge sterile needle
  3. Observe Skin Trauma site
    1. Positive if small red Pustule or Skin Ulcer (2 mm) forms within 24-48 hours of minor Skin Trauma