Differential Diagnosis for Inability to Walk Due to a Pimple Under the Foot

• Single Most Likely Diagnosis:
  • Plantar wart: This is a common condition that can cause significant pain when walking, especially if the wart is located on a weight-bearing area of the foot. The description of a "pimple" could be misleading, as plantar warts can appear as small, hard bumps on the skin.
• Other Likely Diagnoses:
  • Ingrown toenail: An ingrown toenail can cause pain and swelling, which might be described as a pimple, especially if there's an associated infection.
  • Infected sebaceous cyst: A sebaceous cyst on the foot can become infected, leading to pain and swelling that might prevent walking.
  • Abscess: A localized collection of pus under the skin can cause significant pain and might be described as a pimple, especially if it's small.
• Do Not Miss Diagnoses:
  • Osteomyelitis: Although less common, an infection of the bone can present with localized pain and swelling, which might initially be mistaken for a skin lesion like a pimple. Missing this diagnosis could lead to serious complications.
  • Cellulitis: A bacterial skin infection that can spread rapidly and cause serious illness if not treated promptly. It might initially present with localized redness and swelling that could be mistaken for a pimple.
• Rare Diagnoses:
  • Erythema nodosum: A condition characterized by the sudden formation of painful nodules under the skin, often on the legs. It could potentially be described as a pimple if the nodules are small.
  • Panniculitis: Inflammation of the subcutaneous fat, which can cause painful nodules or plaques under the skin. It's less common and might be considered if other diagnoses are ruled out.