What should you know about constant itchy scalp?

Flaking with greasy or dry scale commonly occurs with dandruff or seborrheic dermatitis. Thick, sharply defined scale may occur with scalp psoriasis, which can extend beyond the hairline. Small tender spots or pus-filled bumps can indicate folliculitis. Head lice cause itching and may leave nits firmly attached near the hair roots, especially behind the ears and at the nape. A new dye, shampoo, oil, or styling product can trigger contact irritation. Scratching can break the skin and invite infection, so the scalp appearance matters more than itch intensity alone.

Check the scalp in bright light, separating the hair around the ears and nape, and ask someone to help if needed. Pause recently introduced products and avoid scratching, picking, or sharing combs, hats, and brushes. A pharmacist or clinician can advise whether medicated shampoo is suitable and how long to leave it on. If live lice or firmly attached nits are found, use a recommended head-lice treatment exactly as directed and follow the product instructions for repeat application. Do not combine multiple treatments without advice.

Arrange an appointment if itching lasts despite removing a suspected irritant, if there are recurring flakes or plaques, or if bumps cause hair loss or scarring. Seek prompt care for spreading redness, severe pain, pus, fever, or a swollen neck. A clinician should assess sudden patchy hair loss, bleeding from scratching, or a rash involving the face and ears.

Does the scalp look more like dandruff, seborrheic dermatitis, psoriasis, folliculitis, or lice? Which shampoo or treatment fits my scalp? Could a product be causing the irritation, and what should I use instead?