Differential Diagnosis for Pain in Toenail Bed with Red Line Going Down Middle of Toenail

• Single Most Likely Diagnosis
  • Onychomycosis with secondary bacterial infection: This condition is characterized by a fungal infection of the toenail, which can lead to pain in the toenail bed. The red line going down the middle of the toenail could be a sign of a secondary bacterial infection.
• Other Likely Diagnoses
  • Paronychia: An infection of the skin around the nail, which can cause pain, redness, and swelling in the toenail bed. The red line could be a sign of an abscess or pus accumulation.
  • Onychocryptosis (Ingrown Toenail): A condition where the toenail grows into the surrounding skin, causing pain, redness, and swelling. The red line could be a sign of inflammation or infection.
  • Subungual hematoma: A collection of blood under the toenail, which can cause pain and a red or purple discoloration.
• Do Not Miss Diagnoses
  • Osteomyelitis: A bone infection that can cause pain and redness in the toenail bed. Although less likely, it is a serious condition that requires prompt treatment.
  • Cellulitis: A bacterial skin infection that can cause redness, swelling, and pain in the affected area. If left untreated, it can lead to serious complications.
  • Squamous cell carcinoma: A type of skin cancer that can cause pain and a red or ulcerated lesion in the toenail bed. Although rare, it is a potentially life-threatening condition.
• Rare Diagnoses
  • Melanonychia: A condition characterized by a pigmented streak in the toenail, which can be a sign of melanoma. Although rare, it is a potentially life-threatening condition.
  • Subungual melanoma: A type of skin cancer that occurs under the toenail, which can cause pain, bleeding, and a red or black discoloration.
  • Psoriatic nail dystrophy: A condition characterized by thickening, pitting, and discoloration of the toenail, which can cause pain and a red line going down the middle of the toenail.