Flat warts are caused by infection of the upper skin layers with human papillomavirus (HPV), usually low‑risk types. Most people carry HPV, but warts only appear when additional factors like reduced immunity, skin damage, or poor skin care make it easier for the virus to trigger growths.
Flat warts are considered safe in terms of cancer risk and almost never turn malignant. The main issues are cosmetic discomfort, possible bleeding or soreness if they are repeatedly traumatized, and the tendency to spread or multiply on the skin.
Flat warts can be removed with gentle methods like laser, liquid nitrogen (cryotherapy), radio wave surgery, or electrocoagulation. In some cases, surgical excision with histology is used, especially if the diagnosis is unclear. Self‑cutting, burning, or picking warts is unsafe and can cause bleeding, infection, scarring, and misdiagnosis. Even after removal, new warts can appear, so follow‑up and prevention are important.