Anal warts are usually small growths of abnormal tissue around the anus. The warts may appear as small nodules or have a coralline appearance. The lesions can be tan or pink in colour. The warts may be associated with bleeding from local irritation, itch, burning and the production of moisture.
The warts are a skin response to infection with human papillomavirus. This occurs through sexual activity. Most infections are due to HPV 6 and 11. These subtypes have little or no risk of causing anal cancer. About 10% of anal warts are due to subtypes 16 and 18 and this does lead to an increased risk of anal cancer.
The progression from particular subtypes of HPV infection to anal cancer is slow and not inevitable. There is usually the intervening stage of anal dysplasia where the anal skin is becoming unstable, abnormal and progressing towards a clear cancer. The stages of anal dysplasia are best kept under surveillance by specialist doctors who perform high resolution anoscopy (dedicated microscopic assessment of the anus) which allows identification and mapping of the suspect lesions.
The Gardasil vaccine is currently offered to young people before they become sexually active. The vaccine confers protection against subtypes 6, 11, 16 and 18. The benefit is most evident before exposure to HPV in younger patients. However, even after exposure to the HPV in older patients with development of warts, vaccination may delay or prevent progression to dysplasia and prevent disease from exposure to other subtypes of HPV.
Symptomatic or even unsightly anal warts may be excised under general anaesthetic. In this surgery, the anal warts evident at the time of examination are excised. This does not eradicate the actual virus and the disease may recur. Excision of anal warts can be painful and although the day surgery is relatively brief; pain relief, Sitz baths and laxatives are required. Follow up in the rooms several weeks after allows discussion of the pathology and a check of wound healing.