Differential Diagnosis for Unilateral and Bilateral Pedal Edema

Single Most Likely Diagnosis

• Lymphedema: This condition is characterized by the abnormal accumulation of protein-rich fluid in the interstitial tissue, leading to swelling of one or both legs. It can be primary (inherited) or secondary (acquired) due to surgery, infection, or trauma affecting the lymph nodes.

Other Likely Diagnoses

• Deep Vein Thrombosis (DVT): A blood clot in the deep veins of the legs can cause unilateral swelling, pain, and warmth. It's a common cause of unilateral pedal edema.
• Cellulitis: A bacterial infection of the skin and subcutaneous tissue, often causing redness, warmth, swelling, and pain, typically affecting one leg.
• Lipedema: A chronic condition characterized by the abnormal growth of fat cells in the legs, leading to swelling and pain, often affecting both legs.
• Chronic Venous Insufficiency: A condition where the veins have problems returning blood from the legs to the heart due to valve issues, leading to bilateral swelling, varicose veins, and skin changes.

Do Not Miss Diagnoses

• Compartment Syndrome: A serious condition resulting from increased pressure within a muscle compartment, which can lead to nerve and muscle damage. It's a medical emergency that can cause severe pain, swelling, and pallor in one leg.
• Necrotizing Fasciitis: A life-threatening infection that destroys the tissue under the skin, including fat and the tissue covering the muscles (fascia). It requires immediate medical attention and can present with severe pain, swelling, and skin changes, often in one leg.
• Osteomyelitis: An infection of the bone, which can cause pain, swelling, and redness in the affected limb, potentially leading to more severe complications if not treated promptly.

Rare Diagnoses

• Fabry Disease: A genetic disorder that can lead to the accumulation of a particular type of fat in the body's cells, affecting many parts of the body and potentially causing pedal edema among other symptoms.
• Pseudolymphoma: A rare condition that mimics lymphoma but is not cancerous, which can cause swelling and other symptoms in the legs.
• Sarcoidosis: An inflammatory disease that can affect multiple organs in the body, including the skin, and may cause swelling in the legs among its myriad of possible manifestations.
• Erythromelalgia: A disorder characterized by burning pain, heat, and redness in the hands and feet, which can also lead to swelling, though it's more commonly associated with other symptoms.