Differential Diagnosis for Flat Deep Spots on Feet and Ankles in Prior Meth Users

• Single most likely diagnosis:
  • Methamphetamine-induced skin lesions: This condition is commonly seen in individuals with a history of methamphetamine use. The lesions are often described as flat, deep spots and can be found on the feet, ankles, and other areas of the body. The exact mechanism is unclear, but it's thought to be related to the drug's effects on blood vessels and skin health.
• Other Likely diagnoses:
  • Cellulitis: A bacterial skin infection that can cause redness, swelling, and deep spots on the skin, particularly in areas like the feet and ankles.
  • Abscesses: Pus-filled pockets that can develop in the skin, often as a result of bacterial infection, and can appear as deep spots.
  • Poor circulation-related ulcers: Methamphetamine use can lead to poor circulation, increasing the risk of developing ulcers on the feet and ankles.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Necrotizing fasciitis: A rare but life-threatening bacterial infection that can cause deep tissue damage and necrosis, often starting with symptoms like redness, swelling, and pain in the affected area.
  • Gangrene: A condition characterized by tissue death due to lack of blood supply, which can be a complication of poor circulation or infection.
• Rare diagnoses:
  • Pyoderma gangrenosum: A rare skin condition characterized by the development of large, painful ulcers, often on the legs.
  • Vasculitis: Inflammation of the blood vessels, which can cause a range of symptoms including skin lesions and ulcers.