Explain the cause of cold feet?

Usually the. circulation is compromised. It can be small vessels or large vessels. small vessels go into a spasm and this is called raynauds. Larger vessels if occluded may need a stent or a bypass. (Large vessel disease is more serious.)
Cold feet. This is usually a circulation issue . Edema can be a factor as it can compress blood vessels . See your podiatrist for an evaluation and assistance.
Some various causes. With cold feet, we usually think of circulation as being a problem. But in most case i've seen that is not the case. If you have any swelling in your feet and ankles, this can cause your feet to be cold as well. If your feet sweat a lot this can also make your feet feel cold.