What are the causes of unilateral pedal (foot) and ankle edema (swelling)?

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Last updated: February 10, 2025 • View editorial policy

Differential Diagnosis for Unilateral Foot and Ankle Swelling

Single Most Likely Diagnosis

  • Cellulitis: This is a common and likely cause of unilateral foot and ankle swelling, often resulting from a bacterial infection of the skin and soft tissues. It is characterized by redness, warmth, swelling, and pain in the affected area.

Other Likely Diagnoses

  • Deep Vein Thrombosis (DVT): DVT can cause unilateral swelling of the foot and ankle due to a blood clot in the deep veins, which can lead to obstruction of blood flow.
  • Trauma or Injury: A recent injury, such as a sprain or fracture, can cause swelling in the foot and ankle.
  • Lymphedema: This condition involves the abnormal accumulation of protein-rich fluid in the interstitial tissue, leading to swelling, often affecting one limb.
  • Gout or Pseudogout: These conditions can cause sudden, severe swelling and pain in the foot and ankle, often affecting the big toe.

Do Not Miss Diagnoses

  • Compartment Syndrome: A serious condition that occurs when pressure within the muscle compartments increases, leading to inadequate blood supply to the tissues. It requires prompt diagnosis and treatment to prevent permanent damage.
  • Osteomyelitis: A bone infection that can cause swelling, pain, and redness in the affected area, which can lead to serious complications if left untreated.
  • Necrotizing Fasciitis: A life-threatening infection that affects the tissue beneath the skin and surrounding muscles and organs, requiring immediate medical attention.

Rare Diagnoses

  • Erythromelalgia: A rare disorder characterized by burning pain, heat, and redness in the hands and feet, which can also cause swelling.
  • Klippel-Trenaunay Syndrome: A rare congenital condition that affects blood vessels, soft tissues, and bones, leading to swelling, pain, and other symptoms in the affected limb.
  • Lipedema: A rare condition characterized by the abnormal accumulation of fat in the legs, which can cause swelling, pain, and other symptoms.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.