What to know about a badly itchy scalp

Look for flakes, thick plaques, sores, bumps, broken hairs or attached nits, and consider whether a new hair product preceded the itch. These clues guide the right next step.

Loose white or oily flakes with scalp irritation can occur with dandruff or seborrheic dermatitis. Sharply defined, thicker scale may accompany scalp psoriasis. Tender or pus-filled bumps can reflect folliculitis, while irritation around the hairline may follow dye, fragrance or styling products.

Head lice cause scalp itching and may leave nits firmly attached near the roots; ordinary flakes brush away more easily. Scratching can create small wounds and secondary infection regardless of the original cause.

Pause recently introduced dyes, sprays, oils or fragranced products. Wash with lukewarm water, rinse thoroughly and avoid using fingernails to lift scale. A pharmacist or clinician can help select a medicated shampoo based on whether the pattern fits dandruff, inflammation or another diagnosis.

If lice are suspected, confirm live lice before treatment and check close household contacts. Follow the product instructions carefully; repeated or mixed treatments can irritate the scalp without improving an incorrect diagnosis.

Arrange prompt care for spreading redness, warmth, swelling, pus, fever or significant tenderness. Sudden patchy hair loss, broken hairs with scaling, or a boggy swollen area also needs examination rather than repeated cosmetic treatment.

Schedule a non-urgent review when the itch repeatedly disrupts sleep, persists despite gentle care, or returns as soon as medicated shampoo is stopped. Bring the products you use so possible irritants can be identified.

Ask whether testing is needed for fungus or product allergy, how medicated shampoo should contact the scalp, whether prescription lotion is appropriate, and how to protect hair while the underlying inflammation is treated.