Genital warts are a sexually transmitted infection caused by certain types of human papillomavirus . They may be flat or project out from the surface of the skin, and their color may vary; brownish, white, pale yellow, pinkish-red, or gray. There may be a few individual warts or several, either in a cluster or merged together to look cauliflower-shaped. They can be itchy and feel burning. Usually they cause few symptoms, but can occasionally be painful. Typically they appear one to eight months following exposure. Warts are the most easily recognized symptom of genital HPV infection.