**8. Anal warts**

Anal warts, also known as condyloma acuminata, are growths of tissue localised in the area around and inside the anus, usually caused by human papillomavirus (HPV).

The Human Papilloma Virus (HPV) used to be thought as one of the most common sexually transmitted diseases (STds) [140]. The estimated incidence of HPV infection is high, with 14 million persons infected annually and 79 million persons with prevalent infection [141]. Its family (Papillomaviridae) consists of more than 120 viruses presenting a tropism toward either the cutaneous or mucosa epithelium, however the vast majority (90%) of anal warts are caused only by two low-risk HPV subtypes: 6 and 11 [142]. Further HPV-associated diseases include other mucocutaneous warts as well as cervical, anal, vaginal, vulvar, penile, and oropharyn-geal cancers.

Anogenital warts (AGWs) diagnosis is most often based on their clinical appearance, and tests for the presence of HPV are not recommended for their diagnosis. They firstly appear as tiny spots or growths, whose dimensions may rapidly increase even covering the anal area. Usually, they do not cause any pain or discomfort. Some patients may experience itching, bleeding, mucus discharge, or a feeling of a lump or mass in the area. Histologic examination of biopsy specimens can be performed to rule out intraepithelial or invasive squamous cell carcinomas (SCCs), which can coexist with or appear similar to AGWs.

Therapeutic options for the treatment of anal warts range from topical medical therapies to surgery. Many treatment modalities for anal warts are primarily focused on destroying or removing the warts locally rather than eliminating the infection [143]. There are several factors that influence the choice of treatment modality, such as location of the warts (all intra-anal or rectal warts should be managed by a specialist), number of lesions, patient's ability to apply prescribed creams or gels, patient's preference, cost of the treatment and patient's immunosuppression status.

Treatment plans can be classified either as patient self-administered modalities (for warts locat-ed on the perianal skin only) or treatment administered by a professional (for lesions in an intra-anal or rectal mucosa location).

Patient-applied treatment consists of topical medications includig podophyllin, trichloroacetic acid, bichloroacetic acid, sintecatechins and imiquimod or 5-fluorouracil that can be safely applied at home. Recurrence rates after topical medications widely range from 6.5–55%, being sinecatechins the most effective treatment with eradication rate similar to other topically applied treatments, but the lowest recurrence rate [144–146]. Moreover, patient-applied treatment side effects, which are similar for all the ointments and include redness, irritation or a burning sensation, are reported by only 1 out of 3 treated patients.

Following the center for disease control and prevention recommendations, treatments administered by a medical provider include 80–90% trichloroacetic acid (TCA) application, cryotherapy with liquid nitrogen or surgery/electrosurgery [147]. Just as for haemorrhoids, all of the procedures can be offered in an outpatient setting only to patients having small perianal warts, once the conservative treatment fails. Larger lesions require surgery performed in an operating theatre.

TCA has an erosive and chemically destructive activity; its application on AGWs burns and cauterises skin lesions. Its destructive activity may extend to nearby healthy skin, thus care must be taken during application. It is not recommended for intra-anal use. Success rates are satisfactory, ranging from 70 to 81% [148, 149], but recurrence rate is high: 36% [149].

Cryotherapy seems to be the best therapeutic. The treatment consist of freezing lesions using a liquid nitrogen cooling probe, which results in necrosis and further clearance of destroyed tissue. Complications can include the destruction of healthy skin, and ulcers or scar formation. Even if eradication and recurrence rates are similar to TCA (86% and 39% respectively) [148, 149], cryotherapy is usually preferred because it is cost effective, minimally invasive, painless and can be applied to intra-anal warts.

#### *Ambulatory Surgery for Perianal Disease DOI: http://dx.doi.org/10.5772/intechopen.97119*

Surgical excision is the oldest approach, but for patients suffering from a giant condyloma (Buschke-Loewenstein tumour) it may be the treatment of choice [150, 151]. A more contemporary surgical approach, electrosurgery, is a very effective technique with a clearance rate of 94% [152] but can be painful and requires local or intravenous anaesthesia, thus cannot be performed in an ambulatory setting.

Whether specialist–applied treatment is performed in the operating room or in an ambulatory setting, it usually has satisfactory eradication rates, but also high recurrence rate, ranging from 25 to 40% [152] discouraging clinical use. Actually, all of these modalities are targeted to remove warts locally and do not destroy all the very small or subclinical lesions in the surrounding healthy-looking skin, thus increasing the risk of recurrence.
