When people ask what causes Alopecia, they have to keep in mind what Alopecia really is. Alopecia is the medical term for hair loss. But that hair loss can be very broad. You can have Androgenetic Alopecia, which is male pattern baldness. You can have Alopecia Areata which is autoimmune area of hair loss where you get that small patch. Alopecia Totalls and Alopecia Universalis which are other forms of Alopecia Areata but of more diffuse, for example affecting the entire scalp, or, in the case of Alopecia Universalis there is complete loss of hair everywhere on the body, scalp and face. In retrospect, it is important to understand which type of Alopecia you are referring to in order to get the proper treatment. So, understand that you need to see a hair loss specialist and then you can be on your way to getting your hair back.