Differential Diagnosis for Middle Toe Nail Bed Redness and Pain

• Single most likely diagnosis:
  • Subungual hematoma: This condition is characterized by a collection of blood under the nail, often due to trauma, which can cause pain and redness, especially if the hematoma is located in the middle of the toenail bed.
• Other Likely diagnoses:
  • Onychomycosis (fungal infection of the nail): While more commonly associated with changes in nail texture and color, advanced cases can lead to inflammation and pain.
  • Paronychia: An infection of the skin around the nail, which can extend under the nail and cause redness and pain in the nail bed.
  • Ingrown toenail: A condition where the nail grows into the surrounding skin, causing pain, redness, and swelling, potentially affecting the nail bed.
• Do Not Miss diagnoses:
  • Osteomyelitis (bone infection): Although less common, an infection of the bone beneath the nail can cause severe pain and redness, and if missed, can lead to serious complications.
  • Cellulitis: A bacterial skin infection that can spread and cause severe illness if not treated promptly.
  • Diabetic neuropathy or ulcer: In patients with diabetes, unmanaged foot ulcers or neuropathy can lead to severe infections or gangrene if not addressed.
• Rare diagnoses:
  • Melanoma: A type of skin cancer that can present as a pigmented lesion under the nail, known as subungual melanoma, which is rare but critical to diagnose early.
  • Glomus tumor: A rare, benign tumor of the nail bed that can cause pain and changes in nail color, often described as excruciating pain with pressure or temperature changes.
  • Squamous cell carcinoma: A type of skin cancer that can rarely occur under the nail, presenting with pain, redness, and changes in the nail or surrounding skin.