Differential Diagnosis for Pimple on Dorsal Distant Index with Clear Drainage and Pain

• Single Most Likely Diagnosis
  • Paronychia: This is an infection of the skin around the nail, which can cause pain, swelling, and pus. The clear drainage and painful nature of the pimple are consistent with this diagnosis, especially given its location on the dorsal distant index finger.
• Other Likely Diagnoses
  • Folliculitis: An inflammation of the hair follicles, which can cause pimples or pustules, often accompanied by pain and sometimes drainage. This could be a consideration if the lesion is related to a hair follicle.
  • Abscess: A localized collection of pus that can cause pain, swelling, and sometimes drainage. While it might not be the first consideration for a small pimple, if the lesion is fluctuant and painful, an abscess could be a possibility.
• Do Not Miss Diagnoses
  • Herpetic Whitlow: A viral infection caused by herpes simplex virus, leading to painful, fluid-filled blisters on the fingers. Although less common, missing this diagnosis could lead to inappropriate treatment and potential spread of the virus.
  • Osteomyelitis or Septic Arthritis: Although rare, if the infection spreads to the bone or joint, it could lead to serious complications. Pain and swelling, especially with systemic symptoms like fever, would warrant further investigation.
• Rare Diagnoses
  • Erysipelas: A type of skin infection that can cause redness, swelling, and pain, typically affecting the upper dermis. It's less common on the fingers but could be considered with appropriate clinical context.
  • Sporotrichosis: A fungal infection that can cause skin lesions, often acquired through skin prick injury from a contaminated source like soil or plants. The diagnosis might be considered in individuals with a history of such exposure.