Differential Diagnosis for Warm Erythematous and Swollen Leg
Single Most Likely Diagnosis
- Cellulitis: This is the most common cause of a warm, erythematous, and swollen leg. Cellulitis is a bacterial infection of the skin and subcutaneous tissues, typically caused by Streptococcus or Staphylococcus species. The presentation of warmth, redness, swelling, and tenderness is classic for cellulitis.
Other Likely Diagnoses
- Deep Vein Thrombosis (DVT): DVT can cause a warm, swollen, and erythematous leg due to the obstruction of blood flow. Risk factors such as recent surgery, immobilization, cancer, or genetic predispositions increase the likelihood of DVT.
- Phlebitis: Inflammation of a vein, often caused by a blood clot, can lead to warmth, swelling, and erythema of the affected leg.
- Lymphangitis: An infection of the lymphatic vessels can cause a warm, swollen, and erythematous leg, often with streaks of redness extending from the site of infection towards the lymph nodes.
Do Not Miss Diagnoses
- Necrotizing Fasciitis: A life-threatening infection of the fascia, which can present similarly to cellulitis but requires urgent surgical intervention. Signs of necrotizing fasciitis include severe pain out of proportion to the appearance of the skin, crepitus, and systemic signs of infection.
- Gas Gangrene: A severe infection caused by Clostridium species, characterized by rapid progression of swelling, pain, and crepitus, with potential for systemic toxicity.
- Septic Thrombophlebitis: A condition where a blood clot in a vein becomes infected, leading to systemic sepsis and potentially life-threatening complications.
Rare Diagnoses
- Erythema Nodosum: An inflammatory condition characterized by tender, erythematous nodules, often on the lower legs. It can be associated with various underlying conditions, including infections, autoimmune diseases, and medications.
- Thrombophlebitis of a superficial vein: Inflammation of a superficial vein, which can cause localized warmth, swelling, and erythema, but is less common and typically less severe than DVT.
- Kawasaki Disease: A rare condition that mainly affects children, causing inflammation in the walls of medium-sized arteries throughout the body, and can present with fever, rash, swelling of the hands and feet, and other systemic symptoms.