A computer model of the surface of HPV-11, a leading cause of genital warts. Image: Scripps Research Institute
Human papillomavirus (HPV) is a hot topic these days thanks to the advent — and attendant controversy — of Gardasil, the vaccine that protects against four strains of this sexually transmitted virus. Discourse centers around HPV-16 and HPV-18, the two HPV strains that together are responsible for 70 percent of cervical cancers and 90 percent of anal cancers. However, Gardasil also protects against HPV-6 and HPV-11, two HPV strains that aren’t associated with cancer but rather with 90 percent of genital warts. While genital warts don’t have the potential to cause cancer and death, they can be very upsetting to the people who develop them.
Every year in the United States, about $200 million is spent to treat genital warts.
Many strains of human papillomavirus can cause warts, and not all of them are sexually transmitted. For instance, HPV-1, HPV-2, and HPV-4 cause warts on the hands and feet and are spread by skin-to-skin contact. About 40 strains of HPV can be transmitted sexually — they are called “mucosal” strains because of their affinity for mucous membranes such as the skin found in the genital, anal, and oral regions. Ninety percent of cases of genital warts are caused by two strains of HPV: HPV-6 and HPV-11. Genital warts are highly contagious and can be transmitted by any type of sexual activity.
Let’s start with a quick overview of genital warts. While it’s quite possible for someone infected with a wart-causing strain of HPV to be completely asymptomatic, the physical appearance of warts can take several forms. They can appear in the genital area, in or around the anus, and (very rarely) in the mouth, lips, palate, or throat. They can also rarely be found on the cervix and vaginal walls. They are soft to the touch and can be raised, flat, or bumpy. They may or may not be itchy or painful. Genital warts can be small or quite large. As you can see, there are a wide variety of ways they can manifest themselves, despite being caused by one type of virus. There are four types:
- condylomata acuminata, which have a “cauliflower-like” appearance
- papular warts, which are dome-shaped papules 1-4 millimeters in diameter
- keratotic warts, which have a thick, “crust-like” layer
- flat-topped papules, which can look like a freckle or might be slightly raised from the surface of the skin
Genital warts usually develop within six weeks to six months after exposure, but could take longer to appear. If our immune systems are healthy, our bodies may be able to fight off the virus — our immune systems are normally able to clear 90 percent of genital-wart infections within two years of exposure. Unfortunately, if the immune system can’t fight off the virus, the infection will become chronic, in which case warts can resurface throughout one’s lifetime. The warts can be removed by a doctor, but you could still transmit the virus to others and you might experience a recurrence of the warts. Smokers’ immune systems are less likely to be able to fight off the infection, and in the case of a chronic infection, smokers’ warts are more likely to return even after being removed by a health care provider. Continue reading