What Causes Swelling And An Itchy Rash Around The Ankles?

For the past 5 years usually in May-July one of my ankles swells up, I get a rash which is itchy and then it goes away. One doctor I saw measured it and my leg was 1/4 larger. He couldn t figure it out. The next year when it happened I didn t have insurance so I went to the emergency room. They took an ultrasound on my leg to see if it was a deep vein thrombosis. My mother died of a heart attack at 66 years old, my grandmother on her side died of a heart attack at 75. I saw a neurologist a year ago and because the swelling had gone done he told me I must have gotten better and sent me home. He told me to contact him when it happened again. I never called him because I m looking for a doctor who wants to invest a little time to figure this out. Any ideas? I am female, 55 years old, pretty healthy, I have Ankylosing Spondylitis and HLAB27.