How effective is topical 5-fluorouracil for actinic keratosis?

Actinic keratosis is a rough, sun-damaged patch made of abnormal surface cells. 5-fluorouracil acts on cells that are dividing quickly, so treated areas may become red, irritated, scaly, crusted and tender. The visible reaction can look worse before the skin repairs itself.

The medicine is often useful when several nearby spots or a wider sun-damaged area need treatment, but it is not a universal choice. A thick, painful, bleeding or rapidly changing lesion may need a different procedure or a biopsy because it could have progressed beyond a surface lesion.

Follow the prescribed application schedule exactly and apply only to the instructed skin. Wash your hands afterwards, keep the medicine away from eyes and mucous membranes, and protect the treated area from sunlight. Avoid picking flakes or adding harsh products while the reaction is active.

Ask when to stop, what soothing care is allowed, and whether work or outdoor activities need adjustment. Attend follow-up after the skin has healed. Persistent roughness, a new lump or a lesion that does not respond may require examination rather than repeated self-treatment.

Call the prescriber for severe pain, extensive blistering, pus, fever, spreading redness, eye exposure or an unexpected reaction outside the treatment area. Arrange prompt review for bleeding, a firm lump, increasing thickness or a sore that fails to heal.

Ask which patches are suitable, what reaction is expected, how to protect the area outdoors, what to do after a missed application, and how clearance will be checked.