Brief Answer:
Unilateral Foot swelling needs work up. Likely musculoskeletal sprain

Detailed Answer:
Thank you for asking

I read your question and i understand your concern. Unilateral foot swelling is mostly a local pathology and could have multiple causes. Ankle joint issues, ligament sprains, some fracture at ankle joint can cause foot swelling. Lymphedema or prolonged sitting or legs hanging can cause feet to swell.

if the swelling is above feet and involve legs upto knee joint then other possibilities like deep vein thrombosis, venous insufficiency, bakers cyst and ruptured cysts, infections, gastrocnemius muscles injuries etc can be considered.

To me its likely a musculoskeletal sprain involving ligaments and small joint of feet. Get an MRI, rest for a while, take ibuprofen and keep the leg elevated. Wear a compression stocking and use some muscle relaxants. Foot massage and physiotherapy exercises will also help.

Talk to your podiatrist or orthopaedic doctor and let them sort out other possibilities for it and clinically correlate your symptoms.

I hope it helps. Take good care of yourself and dont forget to close the discussion please.

Regards
Khan

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