How long does topical 5-fluorouracil take to work for actinic cheilitis?

Actinic cheilitis is sun-related damage affecting the lip, often with dryness, scaling, roughness, or colour change. 5-fluorouracil targets abnormal surface cells, so the treated area may become red, sore, scaly, or crusted as the medicine acts. This reaction can be expected, but its intensity and duration vary with the area treated, the product instructions, and individual sensitivity. Improvement is assessed after the prescribed course and recovery, not by stopping as soon as the lip looks irritated.

Apply only the amount and frequency prescribed, to the location your clinician identified. Wash hands after application, avoid licking the medicine, and protect the lips from sunlight as advised. Do not cover the area, add soothing products, or change the schedule without checking first. Keep follow-up because persistent actinic cheilitis may need reassessment, and a sore or thickened area may require a different evaluation.

Ask for prompt advice if swelling makes eating or drinking difficult, pain is severe, the reaction spreads beyond the intended area, or you develop pus, fever, or rapidly worsening symptoms. Seek urgent help for facial swelling with breathing difficulty. A lip area that remains ulcerated, bleeds, becomes thickened, or fails to heal after treatment should be reviewed rather than assumed to be treatment irritation.

Ask how to recognise the expected treatment reaction, when your course ends, which lip products are compatible, and what to do after a missed application. Confirm when the treated lip should be examined and how persistent crusting, ulceration, or thickening will be assessed.