Differential Diagnosis for Left Ankle and Foot Symptoms
Single Most Likely Diagnosis
- Ankle Sprain: The presence of tenderness with palpation anterolaterally, mild swelling, and the absence of gross deformity or trauma suggest a possible ankle sprain, which is a common injury. The anterolateral location is consistent with an inversion-type sprain, the most common type of ankle sprain.
Other Likely Diagnoses
- Peroneal Tendinitis: Given the tenderness on the anterolateral aspect of the ankle, peroneal tendinitis is a plausible diagnosis. This condition involves inflammation of the peroneal tendons, which run along the outside of the ankle.
- Psoriatic Arthritis: The presence of dried skin from psoriasis lesions and the absence of other clear trauma or infection signs suggest that psoriatic arthritis could be a contributing factor, especially if the patient has a history of psoriasis. This condition can cause joint pain, swelling, and stiffness.
- Ankle Synovitis: Inflammation of the synovial membrane surrounding the ankle joint could explain the mild swelling and tenderness without significant trauma history.
Do Not Miss Diagnoses
- Deep Vein Thrombosis (DVT): Although less likely given the lack of significant swelling or erythema, DVT is a critical diagnosis not to miss due to its potential for severe complications, including pulmonary embolism. The presence of +2 dorsalis pedis pulse makes this less likely but does not rule it out entirely.
- Osteomyelitis or Septic Arthritis: These infections, although less common in the absence of clear trauma or systemic signs of infection, are critical to consider due to their potential for severe morbidity. The lack of erythema, bruising, or significant pain reduces the likelihood but does not eliminate these possibilities.
- Compartment Syndrome: This is a medical emergency characterized by increased pressure within a muscle compartment, which could present with pain out of proportion to the physical findings. The absence of significant pain or paresthesias makes this less likely, but it should always be considered in the differential for limb pain and swelling.
Rare Diagnoses
- Erythromelalgia: A rare disorder characterized by burning pain, heat, and redness in the hands and feet. The absence of erythema and the specific location of pain make this less likely.
- Complex Regional Pain Syndrome (CRPS): A condition characterized by chronic pain, inflammation, and hypersensitivity after an injury or trauma. The lack of significant trauma history and the absence of widespread pain or sensory changes make this a less likely diagnosis.
- Gout or Pseudogout: These conditions involve sudden, severe joint pain and swelling, often without a clear history of trauma. The absence of significant pain, especially in the mid or forefoot, and the lack of erythema or bruising make these diagnoses less likely.