Differential Diagnosis for Swelling of Left Index Finger

• Single most likely diagnosis
  • Trauma or injury: This is the most common cause of finger swelling, often resulting from a blow to the finger, a cut, or a crush injury. The swelling can be due to bleeding into the soft tissues or inflammation.
• Other Likely diagnoses
  • Infection (cellulitis or abscess): Bacterial infections can cause swelling, redness, and warmth of the skin. This could be due to a break in the skin that allows bacteria to enter.
  • Arthritis (osteoarthritis, rheumatoid arthritis, or psoriatic arthritis): Various forms of arthritis can cause swelling in the fingers, including the index finger, due to inflammation of the joints.
  • Gout: A form of arthritis characterized by sudden, severe attacks of pain, swelling, redness, and tenderness, often occurring at the base of the big toe but can also affect other fingers.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Compartment syndrome: A serious condition resulting from increased pressure within a muscle compartment, which can lead to muscle and nerve damage. It requires immediate medical attention.
  • Necrotizing fasciitis: A severe infection that destroys the tissue under the skin, including fat and the tissue covering the muscles (fascia). It's a medical emergency.
  • Osteomyelitis: An infection of the bone, which can cause pain, swelling, and redness. If not treated promptly, it can lead to serious complications.
• Rare diagnoses
  • Sarcoidosis: A disease characterized by the growth of tiny collections of inflammatory cells (granulomas) in any part of the body — most commonly the lungs and lymph nodes — but can also affect the skin and joints.
  • Tendon or ligament injury: While not as common as other causes, injuries to the tendons or ligaments can cause swelling and pain in the affected finger.
  • Raynaud’s phenomenon: A condition that affects blood flow to the fingers and toes, and sometimes the ears, nose, and lips, causing them to turn blue or white in response to cold or stress, which might lead to swelling in some cases.