Up close: Compare descriptions of scalp conditions

It isn't always easy to tell what's causing your scalp problems. While dandruff is responsible for most flaky irritated scalps, two less common conditions also cause persistent flaking and scalp irritation: scalp psoriasis and seborrhoeic dermatitis. Symptoms such as flaking and itching may also be caused by overshampooing, allergic reactions to hair products, or low humidity.

• Mild to moderate dandruff: typically waxy white or grey flakes

• Seborrhoeic dermatitis: typically greasy, yellowish and crusty patches, often with redness, mainly found on the scalp near the forehead

• Scalp Psoriasis: typically sharply defined red patches covered by flakey white scales or silvery plaques