Actinic keratosis on the scalp

The patch may be easier to feel than see: fingertips can notice a sandpaper-like area, adherent scale or a small crust. Its colour may be pink, red, tan or close to the surrounding skin. Several spots can merge across a chronically exposed scalp, while hair can hide their edges and make self-monitoring difficult.

Actinic keratosis reflects ultraviolet injury in surface skin cells. It is premalignant rather than automatically cancerous, but some lesions can develop into squamous cell carcinoma. Examination helps separate it from dermatitis, psoriasis and other scaly scalp disorders.

Ask a dermatologist to inspect the whole scalp under good light, including areas covered by hair. Note tenderness, bleeding and the date you first detected the texture. Do not peel off scale before the visit, as the intact surface can provide useful diagnostic information.

A small number of distinct lesions may be treated individually, including with cryotherapy. When there are many changes over an exposed zone, a field treatment such as a prescribed cream or photodynamic therapy may be considered. Expect the clinician to explain redness, crusting, washing, hair care and sun avoidance during recovery.

Bring forward the assessment for a lesion that grows, becomes distinctly raised or hard, stays sore, bleeds repeatedly or forms an ulcer that fails to close. These are reasons for prompt evaluation, not proof of cancer. Severe swelling, spreading redness, discharge or fever after treatment should be reported because the scalp may need assessment for infection or an excessive reaction.

Discuss whether the pattern calls for spot treatment or treatment of the full exposed field. Ask how to manage shampooing and headwear, whether any thick area needs biopsy, what reaction is expected, and when you may safely restart usual scalp products.