What Causes Rapid Weight Loss And Index Finger And Hand Turning Blue In Color?

Just foud out about a friend of mine who is in another country and has recently traveled to Viatnam. her index finger goes blue and so does her hand. She has been trying to lose weight and has stopped and has noticed rapid weight loss now. use to be able to run up and down 250 stairs now after one fligt gets short of breath. Wanted to know if u felt that this is lupus.