Dr. Emily Iker, M.D., is the Director of Lymphedema Center in Santa Monica, and a lymphedema patient herself. Iker says that lymphedema causes your arms or legs to get swollen, and it often only occurs in one limb. Lymphedema happens because of some form of blockage in your lymphatic system, which is part of your immune system, she says. This means lymph fluid can’t drain properly, and the fluid buildup leads to swelling. She says that there are two kinds of lymphedema, primary and secondary. Primary means it happens on its own, and is sometimes diagnosed on babies or kids. But secondary, which is more common, occurs when lymphedema is caused by another condition, such as cancer. We don't know for sure which Ayala has.