Swollen Foot More Condition_symptoms What Could Be Causing A Cold, Blue Swollen Foot On One Side?

What could be causing a cold, blue swollen foot on one side? - swollen foot more condition_symptoms

My father is 69 years. He recently developed swollen; touch blue and cool his left foot. This is) only the left foot and the foot (healthy leg. It is sensitive when it is pushed forward. It has a little swelling. I looked at the symptoms, but can not find, what with all the symptoms match. I thought of a deep venous thrombosis or thrombophlebitis, but it would take until hot, not cold. Hot foot it for the infections ... not cold.