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One of the common reason of one sided ankle swelling is incompetent veins (varicose veins). A stagnated blood flow in the veins can also cause blister, which is recurrent, does not heal. Following measures can help in healing of blister and swelling;
1) Avoid prolonged standing or walking for long distances in a single stretch.
2) Whenever she sits; keep legs elevated on a chair or a sofa or stool. Do not hang the legs, otherwise gravity will increase the swelling.
3) Exercises / physical therapy
a) Lie down straight and raise leg and feet for 10-20 seconds. Repeat this for ten times (twice a day whole set).
b) When she sits; pull the feet towards her for 10-20 seconds. Repeat it for ten times twice a day.
4) Raise leg end of the bed by 6 inches.
She would need a colored doppler study to confirm the diagnosis.
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