Is Vasculitis/ Ischemia Foot Could Get Triggered In An Individual

Is Vasculitis/ Ischemia foot could get triggered in an individual with high sugar if he has visited a water park or swimming pool recently. My question may appear silly, but One of my friend's sister living in Mumbai India got the disease. Doctors are not able to find the exact reason what triggered it. I recently visited them and found the family not able to find real cause of the disease. She was living absolutely normal life before this. Pl.let us know probable cause and cure. Thanks.