What to expect from topical 5-fluorouracil for Bowen's disease

Bowen's disease is an early form of squamous cell carcinoma in situ, meaning abnormal cells are confined to the outer skin layer. 5-fluorouracil interferes with those abnormal cells when applied to the prescribed patch. The area may look worse before it looks better because inflammation brings the treatment reaction to the surface. The visible border may not show the full extent of abnormal skin, which is why diagnosis, treatment instructions, and review should come from a dermatologist.

Follow the exact schedule and apply only to the marked or described area. Wash hands before and after use, avoid the eyes and mouth, and keep the medicine away from other people and pets. Do not pick scale, shave over the patch without guidance, or add dressings and creams that were not recommended. Gentle cleansing and protection from sunlight can make care easier. Arrange time for the skin to look inflamed, and keep the follow-up appointment so the dermatologist can assess healing and decide whether further treatment is needed.

Contact the treating team if pain, swelling, blistering, drainage, or redness becomes difficult to manage, or if irritation spreads beyond the intended area. Seek urgent help for facial swelling with breathing difficulty. A persistent thickened, bleeding, ulcerated, or growing patch after treatment needs prompt review; do not assume it is only leftover irritation.

Why is topical treatment suitable for my lesion, and what other options were considered? What reaction should I expect, how should I care for the area, and what signs mean I should pause? How will you confirm that the patch has healed appropriately?