I’m a man in my 30s, and for almost a year I’ve been dealing with persistent white and sometimes yellowish flakes on my scalp. Some days it looks like simple dandruff, and other days the skin feels a bit greasy and itchy, especially around the sides of my scalp. I’ve been confused about whether this is regular dandruff or something stronger like seborrhoeic dermatitis. It’s embarrassing when flakes fall onto my dark shirts.