HI I Have Recently Been Developing Small White Spots On

HI I have recently been developing small white spots on my shins, front of thighs, forearms, and back of upper arms. Some are as white as confetti. Most are smaller and not totally de-pigmented. My doctor diagnosed it as vitiligo and seemed quite sure about it. But I really dont't that's what it is. I sense the spots are coming from a vitamin deficiency, idiopathic guttate hypomelanosis, fungal or something else. What do you think?