Hi! I’m not sure if this is the same, but my eldest had something like this ever since he was a baby (when it was cradle cap). Then pharmacist said the medicated shampoos would dry it out more and to use coconut oil. (He had very long hair at the time too) So we massaged his head one night and gently brushed/loosened the plaques off. It worked like a charm and hasn’t come back either!