An itchy scalp can be caused by a variety of common factors including dandruff (seborrheic dermatitis), dry scalp, allergic reactions to hair products, scalp psoriasis, fungal infections like ringworm (tinea capitis), head lice, and even stress. Dandruff is the most common cause, involving flakes and inflammation of oil-secreting glands on the scalp that leads to itching and flaking. Allergic reactions or sensitivities to shampoos, conditioners, dyes, or styling products can also cause scalp irritation and itchiness. More serious causes like fungal infections or psoriasis may cause additional symptoms such as scaling, redness, or hair loss. Stress can contribute or worsen existing scalp conditions resulting in itching. Treatment depends on the underlying cause but often involves medicated shampoos, avoiding irritants, and sometimes prescription medications for infections or psoriasis.