Human Papillomavirus (HPV)


HPV stands for human papillomavirus. HPV is a collection of 150 related viruses that can cause a variety of different problems of the genital and anal skin. It is the most common sexually transmitted infection (STI) and can cause genital and anal warts, a precancerous change called anal intraepithelial neoplasia (AIN), and anal cancer.


HPV is an STI that is passed from skin-to-skin contact through vaginal, anal or oral sex with someone who has the virus. HPV infection can also occur without sexual intercourse, as any direct contact with affected skin or bodily fluid from an infected person can cause HPV infection. HPV is very common and most people get infected with HPV at some point in their lives.


In most cases HPV infection does not result in any signs or symptoms at all. HPV infection can lead to a variety of different problems in and around the anus. These include anal warts, precancerous changes in the skin (AIN), or in rare cases anal cancer.

  • Anal warts (condyloma acuminata) are small white or flesh-colored growths that can occur on the skin around the anus and inside the anal canal. They can range from very small to large and extensive. Warts are usually painless and may be noticeable just as bumps on the skin. They may cause itching, bleeding or mucus discharge from the anus.
  • AIN is a precancerous change in the skin or lining of the anus that can be flat like a plaque or raised like a mass. AIN is also painless and often does not cause symptoms.
  • Anal cancer is cancer of the skin around the anus and the lining of the anal canal. Anal cancer can cause anal pain, bleeding, mucus discharge and accidental bowel leakage.



HPV is diagnosed by the presence of the wart, an anal swab for abnormal cells (pap) or on sampling of the skin (biopsy). During examination your doctor will look at the skin around the anus and may use a lighted instrument called an anoscope to look at the lining inside the anus. This exam also includes checking the genital and groin area for any skin changes. If there are any changes in the skin or anus, your doctor may take a biopsy. This may be performed in the office or in the operating room.


Your doctor may use a lighted instrument called an anoscope to look at the lining inside the anus.


Here are some ways to prevent HPV infection:

  • Do not have sexual contact with people who have anal (or genital) warts.
  • Limit sexual contact to a single partner.
  • Abstinence (Do not have any sexual contact).
  • Always use condoms—this reduces but does not eliminate the risk.
  • Sexual partners should be checked for HPV and other STIs even when there are no symptoms.
  • Vaccination is recommended in men and women under 26 years of age to prevent infection.

Cancer prevention: Removal of anal warts can prevent them from developing AIN and cancer. HPV-positive patients at high risk of developing AIN and anal cancer can be screened by anal cytology (anal pap) or high-resolution anoscopy. AIN and anal cancer can occur even in the absence of warts.


External warts can be treated by applying medication or surgical removal. Internal anal warts typically do not respond to medications, so surgery for internal anal warts is required.

Treatment options for warts include:

Topical medication

  • Freeze the warts (liquid nitrogen)
  • Chemical destruction of the warts (Trichlorocetic acid, podophyllin)


  • Laser Ablation therapy (burning)
  • Cauterization (burning)
  • Excision (removal)

When there are many warts, your surgeon may perform the surgery in stages. An internal examination will also be performed so that any lesions on the inside can also be found and treated.

AIN is typically treated by laser ablation or cautery to destroy the precancerous areas.


Treatment of anal warts and AIN can stop the progression to anal cancer. Unfortunately, even with the best treatments, high-grade (AIN III) lesions come back in more than 50% of patients. Close monitoring after any treatment for AIN III is a must. Some patients will require repeated treatment of new or persistent anal warts or AIN III lesions.


download-(1).pngOverall the risk of developing anal cancer remains very low, but without treatment HPV can progress to anal pre-cancer and eventually anal cancer. AIN I and II can progress to AIN III which can progress to anal cancer. The average time AIN III can take to turn into cancer is about five years.

Certain strains of the HPV virus increase this risk of developing AIN and cancer. Certain patient factors can increase the risk as well: HIV infection, immune suppression, and men who have anal sex with men are at highest risk. Women who have been diagnosed with cervical dysplasia or cancer are also at risk.

For this reason it is important to see your doctor on a regular basis so that they can check for early changes and prevent cancer. If you have any of these factors that increase your risk it is important to work with your doctor to ensure that your risks are decreased as much as possible.


Colon and rectal surgeons are experts in the surgical and non-surgical treatment of diseases of the colon, rectum and anus. They have completed advanced surgical training in the treatment of these diseases, as well as full general surgical training. Board-certified colon and rectal surgeons complete residencies in general surgery and colon and rectal surgery, and pass intensive examinations conducted by the American Board of Surgery and the American Board of Colon and Rectal Surgery. They are well versed in the treatment of both benign and malignant diseases of the colon, rectum and anus and are able to perform routine screening examinations and surgically treat conditions, if indicated to do so.


The American Society of Colon and Rectal Surgeons is dedicated to ensuring high-quality patient care by advancing the science, prevention and management of disorders and diseases of the colon, rectum and anus. These brochures are inclusive but not prescriptive. Their purpose is to provide information on diseases and processes, rather than dictate a specific form of treatment. They are intended for the use of all practitioners, health care workers and patients who desire information about the management of the conditions addressed. It should be recognized that these brochures should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtain the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all the circumstances presented by the individual patient.