Back of the head of a male patient with alopecia totalis. This is a rare form of alopecia where hair falls out over the entire body. Such loss occurs when all the hairs simultaneously enter the resting phase and then fall out about three months later. Causes include various forms of stress, such as surgery or prolonged illness. Many anticancer drugs used in chemotherapy also can cause this condition. Regrowth occurs when the underlying cause is corrected.