Dandruff is a kind of skin disorder that affects the scalp. Dandruff is a condition in which white, dry flakes of dead skin are shed from the scalp. Normally dead skin cells are shed from the scalp, but it results in dandruff only when the scalp starts shedding thick layers of these dead skin particles. Seborrheic dermatitis or Seborrhoea is a disorder of the sebaceous glands which affects the scalp. Seborrhoea produces severe dandruff and a red, itchy scalp. Dandruff rarely causes hair loss or baldness. However, severe seborrheic dermatitis may cause patchy baldness.