Differential Diagnosis for Pain under Lateral Malleus
Single Most Likely Diagnosis
- Peroneal Tendinopathy: This condition is characterized by inflammation or degeneration of the peroneal tendons, which run along the lateral aspect of the ankle, directly under the lateral malleolus. Activities that involve repetitive ankle motion can lead to this condition, making it a common cause of pain in this area.
Other Likely Diagnoses
- Lateral Ankle Sprain: A common injury that occurs when the ankle rolls, causing stress and potentially tearing the ligaments on the outside of the ankle. Pain under the lateral malleolus is a frequent complaint.
- Subtalar Joint Pathology: Issues with the subtalar joint, such as arthritis or instability, can cause pain that is referred to the area under the lateral malleolus due to the joint's location and the distribution of pain from this area.
- Peroneal Nerve Entrapment: The peroneal nerve wraps around the lateral aspect of the fibula (near the lateral malleolus) and can become entrapped, leading to pain, numbness, or weakness in the area it supplies.
Do Not Miss Diagnoses
- Osteochondral Lesion of the Talus: A condition where a piece of cartilage and bone in the talus (ankle bone) becomes damaged. This can cause deep ankle pain and, if missed, can lead to further complications such as arthritis.
- Ganglion Cyst: A lump under the skin that occurs when fluid accumulates, potentially causing pain and discomfort. While not typically life-threatening, missing a ganglion cyst could lead to unnecessary prolonged pain and potential nerve compression.
- Infection or Abscess: Though less common, an infection in the soft tissues under the lateral malleolus could lead to serious complications if not promptly treated, including spread of infection or sepsis.
Rare Diagnoses
- Tumor (Benign or Malignant): Tumors, whether benign like a lipoma or malignant, can occur in the soft tissues around the ankle and cause pain. These are rare but important to consider to ensure proper diagnosis and treatment.
- Erythromelalgia: A rare disorder characterized by burning pain, heat, and redness in the hands and feet. It could potentially cause pain under the lateral malleolus, though this would be an unusual presentation.
- Complex Regional Pain Syndrome (CRPS): A condition characterized by persistent burning pain and inflammation after an injury, which could potentially involve the area under the lateral malleolus. It's rare and diagnosis can be challenging.