Differential Diagnosis for Left Fingers Swelling, Warmth, and Redness

The patient presents with swelling, warmth, and redness of the left fingers, especially the thumb, along with pain on palpation, after having a cast on the left arm for 6 weeks. Here's a differential diagnosis organized into categories:

• Single Most Likely Diagnosis
  • Deep Vein Thrombosis (DVT): Given the recent immobilization due to the cast, DVT is a highly plausible cause. Immobility is a significant risk factor for DVT, which can cause swelling, warmth, and pain in the affected limb.
• Other Likely Diagnoses
  • Cellulitis: A common infection of the skin and subcutaneous tissues that could be facilitated by minor trauma or breaks in the skin, leading to redness, swelling, warmth, and pain.
  • Contact Dermatitis: An allergic reaction or irritation from the cast material could cause localized redness, swelling, and discomfort.
  • Compartment Syndrome: Although less common after the initial immobilization period, it's possible, especially if the cast is too tight, leading to increased pressure within the muscle compartments.
• Do Not Miss Diagnoses
  • Septic Arthritis or Osteomyelitis: Infections within the joint or bone, respectively, which could present with localized signs of infection such as redness, swelling, and pain, and are critical to diagnose early to prevent long-term damage.
  • Necrotizing Fasciitis: A severe infection of the fascia, which could rapidly progress and is life-threatening, presenting with severe pain, swelling, and redness.
• Rare Diagnoses
  • Erythromelalgia: A disorder characterized by burning pain, heat, and redness in the hands and feet, which could be considered if other diagnoses are ruled out.
  • Complex Regional Pain Syndrome (CRPS): A condition characterized by chronic pain, inflammation, and hypersensitivity, typically following an injury, which might present with swelling, redness, and pain in the affected limb.

Each of these diagnoses has a different set of implications for treatment and patient outcomes, emphasizing the importance of a thorough evaluation to determine the underlying cause of the patient's symptoms.