biotin deficiency, vitamin A excess, magnesium deficiency are good possibilities.
Accutane side effects
list biotin deficiency and hypervitaminosis A (too much vitamin A). Accutane is a form of vitamin A. Biotin deficiency causes hair breakage. Too much vitamin A causes many symptoms but include increased changes in skin, hair, and nails, dizziness, fatigue, blurred vision, elevated cerebrospinal fluid pressure (intracranial head pressure).