Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Alopecia universalis ?
    ### Response:
    What causes alopecia universalis? The exact underlying cause of alopecia universalis (AU) is not currently known. AU is an advanced form of alopecia areata (AA), a condition that leads to round patches of hair loss. AA is thought to be an autoimmune condition in which an affected person's immune system mistakenly attacks the hair follicles.
    