Causes of one sided non pitting edema right foot and ankle, no known injury, no pain? no change for 10 days. otherwise healthy. thanks.

LE edema: Seek immediate medical attention in an ER. It could be a clot in your leg or can be a mass(growth) in your abdomen/pelvis(ovary colon) compressing your veins, right heart disease/ emphysema with liver issues or just liver issues . You need to follow up immediately in the an ER ( so appropriate imaging can be done emergently) .

Be aware: This could be a sign of a blood clot - a so called deep vein thrombosis, although this type of swelling tends to be pitting. Nonpitting edema tends to be from lymphatic obstuction or from deposition of certain substances like you see with hypothyroidism(though this tends to be bilateral - on both sides). Nonetheless, you should get this looked at by a doctor sooner rather than later.