Have you started or changed any medication recently? I changed blood pressure tablets from Atenolol to Amlodipine and eventually noticed swollen ankles gradually worsening over 10-12 weeks. When I mentioned it to my specialist, I was changed to Slocinx XL (Doxazosin) where in the space of less than two days my feet, ankles and calves swelled (along with urticarial) and I clearly had an allergic reaction. The second reaction was obvious to me, but the first was so gradual that I simply didn't link the medication and reaction.