Differential Diagnosis for Patient with Red, Swollen, Painful Legs and Feet

Given the patient's history of neuropathy and presentation of red, swollen, painful legs and feet, with negative findings for DVT and normal uric acid levels, and lack of response to initial treatments, the following differential diagnoses are considered:

• Single Most Likely Diagnosis

  • Erythromelalgia: This condition is characterized by burning pain, heat, and redness in the hands and feet, which could be exacerbated by the patient's neuropathy. The lack of response to antibiotics, oral steroids, and topical hydrocortisone suggests a condition that may not be infectious or inflammatory in nature, making erythromelalgia a plausible diagnosis.

• Other Likely Diagnoses

  • Complex Regional Pain Syndrome (CRPS): Given the patient's history of neuropathy, CRPS is a possible diagnosis. It is characterized by chronic pain, inflammation, and hypersensitivity in one of the limbs after an injury or trauma, which could align with the patient's symptoms.
  • Peripheral Artery Disease (PAD): Although less likely given the absence of specific risk factors mentioned, PAD could cause pain and swelling in the legs, especially if the patient has a history of smoking or diabetes.
  • Chronic Venous Insufficiency: Despite the ultrasound ruling out DVT, chronic venous insufficiency could cause similar symptoms of swelling and pain, especially if there's a history of venous problems.

• Do Not Miss Diagnoses

  • Cellulitis with Atypical Bacteria: Although the patient did not respond to antibiotics, it's crucial to consider the possibility of an atypical bacterial infection that may require different antibiotic coverage.
  • Deep Vein Thrombosis (DVT) Missed on Ultrasound: Although the ultrasound was negative, the possibility of a missed DVT, especially in a non-compressible vein or in a patient with a high clinical suspicion, necessitates reconsideration or further imaging techniques like MRI.
  • Osteomyelitis: An infection of the bone, which could be a complication of neuropathy, especially if the patient has a history of foot ulcers or trauma.

• Rare Diagnoses

  • Sarcoidosis: A systemic disease that could cause skin lesions and neuropathy, although it would be less common and might require further diagnostic workup including biopsy.
  • Lymphoma: Certain types of lymphoma can cause skin and neurological symptoms, but this would be a rare and less likely diagnosis without other systemic symptoms.
  • Fabry Disease: A genetic disorder that can cause neuropathic pain, skin lesions, and vascular problems, but it's rare and typically diagnosed at a younger age.