6. Bacterial Infection
Bacterial infections are unusual causes of swollen ankles. The bacteria can accumulate and infect the soft ankle tissues or the joint itself. The infection of the ankle soft tissue is known as cellulitis. It usually appears in the form of blisters. The rash is always red, tender, and feels hot around the affected area. Even though cellulitis is not contagious, it usually spreads rapidly and can affect the whole leg within 24 hours.
The bacterium that causes this type of ankle infection enters the body through cuts or skin tears. People who have cuts, insect bites, or fungal infections are likely to have cellulitis. Other factors that can put you at risk of having cellulitis infection are the use of immunosuppressive medication, being overweight, have a history of edema, or have had lymph node surgery. If you have cellulitis symptoms you should quickly get treatment; untreated cellulitis can severely damage nerves.