Differential Diagnosis for Unilateral Lower Limb Swelling
Single Most Likely Diagnosis
- Cellulitis: This is the most likely diagnosis given the presentation of unilateral lower limb swelling, as cellulitis is a common cause of limb swelling and is often unilateral. It is an infection of the skin and subcutaneous tissues, usually caused by streptococcal or staphylococcal bacteria.
Other Likely Diagnoses
- Deep Vein Thrombosis (DVT): DVT can cause unilateral limb swelling due to obstruction of blood flow. It is a significant consideration, especially if there are risk factors such as recent surgery, immobilization, or cancer.
- Lymphedema: This condition involves the abnormal collection of protein-rich fluid in the interstitial tissue, leading to swelling of the limb. It can be primary (inherited) or secondary (due to surgery, infection, or other causes).
- Trauma or Injury: Direct trauma to the limb can cause swelling due to inflammation, hematoma, or other soft tissue injuries.
Do Not Miss Diagnoses
- Necrotizing Fasciitis: Although less common, this is a life-threatening condition that requires immediate attention. It is characterized by necrosis of the fascia and subcutaneous tissue, often due to a severe bacterial infection.
- Compartment Syndrome: This is a condition where increased pressure within a muscle compartment leads to muscle and nerve damage. It is a medical emergency that can result from trauma, fractures, or severe swelling.
- Malignancy: Certain types of cancer, such as lymphoma or soft tissue sarcomas, can cause limb swelling. While less common, these diagnoses should not be missed due to their significant implications.
Rare Diagnoses
- Filariasis: In endemic areas, filariasis (caused by parasitic worms) can lead to lymphedema and limb swelling.
- Pseudolymphoma: A rare condition that mimics lymphoma but is often benign, it can cause limb swelling among other symptoms.
- Lipedema: A chronic condition characterized by the abnormal growth of fat cells in the legs, leading to swelling and pain. It is often mistaken for lymphedema but has distinct characteristics.