Anal Warts (HPV)

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What are anal warts (HPV)?


Warts are small bumps in the genital area and the anus, raised or flat, or like lentils or cauliflowers. They are caused by human papilloma virus (HPV) infection.

HPV is a very common virus spread during sexual activity or direct skin touching. HPV is usually transmitted through sexual intercourse or directly by hand contact.  70% of women and 24% of straight men have anal HPV infection. The frequency of HPV infection is 60% in gay and 90% in HIV seropositive gay.


There are around 40 HPV types. They cause warts, cancer and precancerous dysplasias in female external genitalia, penis, anus, mouth and tonsils. Anal warts are not limited to the outer skin only but can also be found inside anus. Inside anus, HPV infects only skin cells but not cells of the bowel. Therefore, HPV does not extend over a distance of 5-7 cm from anal opening. In case of skin perianal warts, the internal anal canal should also be examined with high resolution anoscopy and acetic acid. Warts are easily diagnosed by direct eye and proctoscopy. The dysplasias that amy progress to cancer cannot be diagnosed visually. Acetic acid and magnification (high resolution anoscopy) are necessary for detection of dysplasias. Colonoscopy does not help for diagnosis of anal warts or dysplasias. HPV may infect anus by direct sexual intercourse with various objects but also by hand transmission from penis or vagina. Condom use is always necessary during anal intercourse but does not completely protect from HPV infection.


HPV infection, anal warts, anal dysplasias and anal cancer are more common in men and the women who have had more than 15 sexual partners or anal intercourse. Anal cancer is more frequent in women with external genital cancer or dysplasias. Weak immune system is also a very important risk factor for anal warts, dysplasias or cancer. Weak immune system occurs in HIV infection, in long-term treatment with steroids or other medications in transplanted patients, autoimmune disease or inflammatory bowel disease. Smoking worsens HPV infection and its progression to cancer. Anal cancer frequency in gay is equal to cervical cancer frequency before cervical cytology (test-pap).


Anal warts are often perceived as small palpable nodules or because of itching.  They may take a large extent and appear as large irregular surfaces. Precancerous dysplasias do not cause any symptoms and cannot be easily detected because they are soft and flat. Dysplasias are diagnosed only with high-resolution proctoscopy. This examination should be done in high-risk groups mentioned above. Dysplasias can be detected also with anal cytology (a significant percentage is lost) and HPV test. 15% of anal dysplasias progress to anal cancer. Anal warts can be treated with ablation, laser, cryotherapy or creams.


Internal anal warts and dysplasias should be treated only with electroablation as severe bleeding may occur during laser treatment. Anal warts and dysplasias reappear frequently after any treatment. Therefore, a second examination 5-6 weeks post treatment is necessary. Steroid creams should be avoided because they weaken immune system and activate HPV.


A very important issue is HPV vaccination. The 9-valent HPV vaccine prevents 95% of HPV infections including most frequent HPV types and those types that cause cancer. HPV vaccination prevents anal cancer, cervix cancer and mouth cancer. HPV vaccination is provided to men and women up to 26 years and up to 45 years in gay and HIV seropositive. HPv vaccination does not only prevent HPV infection but may also contribute to the treatment of already existing HPV infections (warts, dysplasias) by boosting humoral immunity beyond limited local cellular immunity induced by HPV infection.