What would cause your foot to swell and turn the bottom of your foot and your toes purple & go cold & numb & tingle?

Many things: To name a few co-morbidities that are at play: chf, venous stasis, dependent edema, neuropathy, auto-immune ties in with chronic diarrhea +- reynaud's syndrome, deep venous thrombus......The list could go on. The short......See your doctor soon.

Other extremities: Reynaud's? Is it all extremities? Just one foot? More info would be helpful.

Vascular issue: A vascular issue such as arterioschlerosis or peripheral vascular disease can cause the above symptoms. This happens when an artery becomes occluded and the areas downstream do not receive enough blood/nutrients. Another possibility is raynaud's disease which leads to focal abnormalities in the blood vessels that leads them to have spasms and the symptoms you descibe. You should have a dr. Evaluat.