Sexually transmitted diseases (STDs) are common and they can involve the anus and rectum in both men and women. In this article, the main bacterial and viral STDs that affect the anus and rectum are discussed, including their prevalence, presentation, and treatment.
Key points
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Patients with acute proctitis who have recently practiced anal receptive intercourse and who have anorectal exudates on examination or polymorphonuclear leukocytes detected on Gram stain should be treated with a 1-time intramuscular dose of ceftriaxone 250 mg and doxycycline 100 mg orally twice a day for 7 days while awaiting laboratory results.
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Patients with painful perianal ulcers or rectal mucosal ulcers should be presumptively treated for herpes simplex virus (HSV) and lymphogranuloma venereum chlamydia until diagnosis is established.
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The classic anoscopic examination for gonorrhea includes thick purulent discharge that is expressed from the anal crypts with pressure on the anus.
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Chlamydia serovars D through K are those responsible for urethritis, cervicitis/pelvic inflammatory disease, neonatal disease, and can cause proctitis. Serovars L1, L2, and L3 can cause lymphogranuloma venereum.
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Syphilis typically presents with sores that appear at the location where it entered the body. Extragenital or anal chancres (in contrast with genital lesions) are generally painful and resolve after 3 to 6 weeks whether treated or not. Lymphadenopathy may be present.
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HSV proctitis is suggested by the presence of severe anorectal pain; sacral parasthesias; diffuse ulceration of the distal rectal mucosa; and, at times, difficulty urinating.
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The sexually transmitted diseases discussed are generally treated the same in a human immunodeficiency virus–positive patient. The US Centers for Disease Control and Prevention recommends close follow-up of lesions and symptoms because the risk of recurrent or persistent disease may be higher.
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Acquired immunodeficiency syndrome ulcers are generally higher in the anal canal with a broad base and ulceration that may involve the muscle. Severe pain is common.
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Anogenital warts, or condyloma accuminata, are caused by human papillomavirus (HPV) 6 or 11 in 90% of cases.
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Ninety-five percent of anal cancers are linked to HPV.
Sexually transmitted and infectious diseases of the anus and rectum
General Presentation and Initial Management
Anal or perianal ulcers and proctitis are the most common manifestations of anorectal sexually transmitted infections that bring a patient to the attention of a colon and rectal surgeon. Principles based on prevalence of disease can aid in the work-up and treatment. In the United States, most young, sexually active patients with anal or anal canal ulcers have herpes simplex virus (HSV). Although syphilis is another consideration, the incidence is less common. Even more infrequent are chancroid and donovanosis ulcerations. Diagnosis based on a patients history and physical examination can be inaccurate, thus it is recommended by the US Centers for Disease Control and Prevention (CDC) that all patients who have anal or perianal ulcers be evaluated with serologic tests for syphilis and a diagnostic evaluation for herpes either by culture or polymerase chain reaction (PCR). Human immunodeficiency virus (HIV) testing should be performed on all patients with anal or perianal ulcers who are not already known to be infected. Proctitis from sexually transmitted infections occurs predominantly among those involved in anal receptive intercourse. This inflammation of the rectum can be associated with rectal discharge, pain, and tenesmus. The most common sexually transmitted pathogens involved are Neisseria gonorrhoeae , Chlamydia trachomatis , Treponema pallidum , and HSV. Proctitis from HSV can be especially severe in patients with HIV.
Because results from testing can take more than 48 hours, it is often necessary to begin empiric treatment. Patients with acute proctitis who have recently practiced anal receptive intercourse and who have demonstrable anorectal exudates on examination or polymorphonuclear leukocytes on Gram stain should be treated with a 1-time intramuscular (IM) dose of ceftriaxone 250 mg and doxycycline 100 mg orally twice a day for 7 days while awaiting laboratory results. For patients with painful perianal ulcers or rectal mucosal ulcers, presumptive treatment of HSV and lymphogranuloma venereum (LGV) chlamydia should be initiated.
Reporting
To assist local health authorities in partner notification, assess morbidity trends, and help with appropriate allocation of resources, timely reporting of STDs is necessary. In every state, the following cases should be reported: syphilis, gonorrhea, chlamydia, chancroid, HIV, and acquired immunodeficiency syndrome (AIDS). Requirements for reporting other STDs vary by state.
Prevention
The most reliable way to avoid transmission of STDs is to abstain from oral, vaginal, and anal sex or to be in a long-term, mutually monogamous relationship with an uninfected partner. For persons who are being treated for an STD, counseling that encourages abstinence from sexual intercourse until completion of the course of medication is crucial.
Barriers, such as male latex condoms, are highly effective in preventing the sexual transmission of HIV when used correctly. Condoms can also reduce the risk for other STDs, including chlamydia, gonorrhea, and trichomoniasis. Although data are more limited, consistent and correct use of latex condoms also reduces the risk for genital herpes, syphilis, and chancroid when the infected area or site of potential exposure is covered. Condoms lubricated with spermicides are no more effective than other lubricated condoms in protecting against the transmission of HIV and other STDs. Furthermore, spermicides containing nonoxynol-9 can damage the cells lining the rectum, which may provide a portal of entry for HIV and other sexually transmissible diseases. Therefore, it should not be used as a microbicide or lubricant during anal intercourse by men who have sex with men (MSM) or by women.
Sexually transmitted and infectious diseases of the anus and rectum
General Presentation and Initial Management
Anal or perianal ulcers and proctitis are the most common manifestations of anorectal sexually transmitted infections that bring a patient to the attention of a colon and rectal surgeon. Principles based on prevalence of disease can aid in the work-up and treatment. In the United States, most young, sexually active patients with anal or anal canal ulcers have herpes simplex virus (HSV). Although syphilis is another consideration, the incidence is less common. Even more infrequent are chancroid and donovanosis ulcerations. Diagnosis based on a patients history and physical examination can be inaccurate, thus it is recommended by the US Centers for Disease Control and Prevention (CDC) that all patients who have anal or perianal ulcers be evaluated with serologic tests for syphilis and a diagnostic evaluation for herpes either by culture or polymerase chain reaction (PCR). Human immunodeficiency virus (HIV) testing should be performed on all patients with anal or perianal ulcers who are not already known to be infected. Proctitis from sexually transmitted infections occurs predominantly among those involved in anal receptive intercourse. This inflammation of the rectum can be associated with rectal discharge, pain, and tenesmus. The most common sexually transmitted pathogens involved are Neisseria gonorrhoeae , Chlamydia trachomatis , Treponema pallidum , and HSV. Proctitis from HSV can be especially severe in patients with HIV.
Because results from testing can take more than 48 hours, it is often necessary to begin empiric treatment. Patients with acute proctitis who have recently practiced anal receptive intercourse and who have demonstrable anorectal exudates on examination or polymorphonuclear leukocytes on Gram stain should be treated with a 1-time intramuscular (IM) dose of ceftriaxone 250 mg and doxycycline 100 mg orally twice a day for 7 days while awaiting laboratory results. For patients with painful perianal ulcers or rectal mucosal ulcers, presumptive treatment of HSV and lymphogranuloma venereum (LGV) chlamydia should be initiated.
Reporting
To assist local health authorities in partner notification, assess morbidity trends, and help with appropriate allocation of resources, timely reporting of STDs is necessary. In every state, the following cases should be reported: syphilis, gonorrhea, chlamydia, chancroid, HIV, and acquired immunodeficiency syndrome (AIDS). Requirements for reporting other STDs vary by state.
Prevention
The most reliable way to avoid transmission of STDs is to abstain from oral, vaginal, and anal sex or to be in a long-term, mutually monogamous relationship with an uninfected partner. For persons who are being treated for an STD, counseling that encourages abstinence from sexual intercourse until completion of the course of medication is crucial.
Barriers, such as male latex condoms, are highly effective in preventing the sexual transmission of HIV when used correctly. Condoms can also reduce the risk for other STDs, including chlamydia, gonorrhea, and trichomoniasis. Although data are more limited, consistent and correct use of latex condoms also reduces the risk for genital herpes, syphilis, and chancroid when the infected area or site of potential exposure is covered. Condoms lubricated with spermicides are no more effective than other lubricated condoms in protecting against the transmission of HIV and other STDs. Furthermore, spermicides containing nonoxynol-9 can damage the cells lining the rectum, which may provide a portal of entry for HIV and other sexually transmissible diseases. Therefore, it should not be used as a microbicide or lubricant during anal intercourse by men who have sex with men (MSM) or by women.
Most common pathogens and treatments
Gonorrhea
Over the past few years, reported cases of gonococcal disease have increased in both men and women across all ethnic groups and in all regions of the United States. The CDC states that in 2011 there were 321,849 cases reported in the United States, which is a 4% increase since 2010. Rates among women continue to be higher than those among men, and the age group most frequently affected is 15 to 44 years.
Anorectal gonococcal disease is most common among MSM and women. Transmission is typically by oral-anal or anoreceptive intercourse, although women may also develop anorectal infection by spread from cervical or urethral gonorrhea because they frequently harbor disease in both areas.
Although most women and approximately half of men with anorectal gonorrhea are asymptomatic, patients may experience tenesmus, anorectal pain, constipation, or mucopurulent discharge. To differentiate this from different causes of proctitis, work-up should include a history involving sexual practices, external anal examination, and anoscopy. In general, findings are nonspecific, including erythema and friable mucosa. The classic anoscopic examination for gonorrhea includes thick purulent discharge that is expressed from the anal crypts with pressure on the anus. If anorectal exudate is detected or if a Gram stain of the anorectal secretions shows polymorphonuclear leukocytes, the CDC recommends initiation of treatment with ceftriaxone and doxycycline while awaiting final culture results.
Infection with N gonorrhoeae can Facilitate HIV Transmission with more than a 3-Fold Increase in HIV Transmission Among MSM
Testing for N gonorrhoeae has historically been performed with culture, which has the advantage of identification of the bacteria as well as analyzing antibiotic sensitivities. The culture should be taken by a cotton swab inserted 3 to 4 cm into the rectal vault. This swab is then placed on agar, most commonly Thayer-Martin, because it prevents the overgrowth of other endogenous flora. The specimen must then be transported and stored in a CO 2 -rich environment. The sensitivity of culture for anorectal gonorrhea is poorly reported and ranges from 27% to 85%.
Newer tests with promise are classified as nucleic acid amplification tests (NAATs). The transcription-mediated amplification shows greater sensitivity (100%) compared with culture (66.7%–71%) and similar specificity (>95% vs 99% for culture). This test does not require the careful handling required for culture and can detect gonorrhea and chlamydia simultaneously. In less than 48 hours it can give results, but it is more expensive and cannot provide information on antibiotic susceptibility. There are currently no FDA-approved commercial tests for nongenital testing, but there are 19 states and 12 commercial laboratories that are Clinical Laboratory Improvement Amendments (CLIA) certified and listed in conjunction with the CDC who have standardized methods of testing with good results. In high-risk populations, specifically MSM, the CDC recommends that men who have had receptive anal intercourse during the preceding year be tested for rectal infection with N gonorrhoeae and C trachomatis and states that an NAAT of a rectal swab is the preferred approach.
N gonorrhoeae has shown the ability to develop antimicrobial resistance. In the late 1990s and 2000s fluoroquinolone resistance became widespread leaving cephalosporins as the only recommended antibiotic class for first-line treatment. More recently the minimum concentration of cefixime used to treat gonorrhea has increased, suggesting that its efficacy may be decreasing. For this reason, the CDC’s recommendations for treatment were updated to no longer recommend cefixime. They now include combination therapy with ceftriaxone 250 mg IM and either azithromycin 1 g orally as a single dose, or doxycycline 100 mg orally twice daily for 7 days. This treatment regimen ensures the treatment of both gonorrhea and chlamydia because they are frequent concomitant pathogens. Treatment does not differ in HIV-positive patients.
Chlamydia
With an estimated 2.86 million infections occurring annually in the United States, chlamydia is the most frequently reported bacterial sexually transmitted infection. Chlamydia is most prevalent among sexually active young persons aged 14 to 24 years and non-Hispanic black people. Rectal chlamydia is also common among MSM, with a positivity rate in a screening population of 3% to 10.5%.
There are multiple distinct variations within the species of C trachomatis . Grouped into serovars, D through K are those responsible for urethritis, cervicitis/PID, and neonatal disease, and they can also cause proctitis. Chlamydia can infect the rectum in both men and women, either through receptive anal sex or via spread from the cervix and vagina in women with chlamydia. Although rectal chlamydia is often asymptomatic, similar to gonorrhea it can cause symptoms of proctitis including rectal pain, discharge, or bleeding. The incubation period for Chlamydia is 5 to 14 days.
Testing for Chlamydia should be performed if suspicion arises based on history and examination. Findings for symptomatic proctitis from serovars D to K are similar to gonorrhea, including friable mucosa and mucus discharge. Annual rectal screening has only been shown to be advantageous in MSM who are sexually active. MSM who have multiple or anonymous partners should be screened every 3 to 6 months.
Obtaining a diagnosis for rectal chlamydia can be challenging. Culture is limited to research and reference laboratories because of the technical expertise and expense required. Serology can support the diagnosis, but is not standardized, performed infrequently, and requires a high level of expertise to interpret. There is also a paucity of data for men with rectal infections, which may affect the test’s performance. Antigen detection by swab has generally shown good sensitivity and specificity for urogenital chlamydia; however, for rectal swab, the limited data suggest a sensitivity of less than 50%. Several studies have shown that NAATs on rectal specimens are more sensitive than culture in detecting rectal chlamydia and still have high specificity. In particular, the use of a transcription-mediated amplification method seems to show consistently strong results. Although uniformly validated rectal NAAT is not available, as stated before, some laboratories in the United States have met testing validation requirements under the CLIA regulations and perform NAATs on rectal specimens.
Treatment of Chlamydia proctitis serovars D to K (non-LGV) includes either azithromycin 1 g orally once, or doxycycline 100 mg orally twice a day for 7 days. Either regimen has a greater than 97% efficacy of eradicating the bacteria after 1 week. Abstaining from sex for 1 week after initiation of treatment decreases transmission, and treatment of partners decreases reinfection.
LGV
LGV disease is also caused by the species C trachomatis ; however, the serovars are most commonly L1, L2, or L3. The most common clinical manifestation overall is unilateral tender inguinal or femoral lymphadenopathy. Among those with rectal exposure via anal receptive sex, LGV can result in proctocolitis causing mucoid or bloody rectal discharge, fevers, anal pain, or tenesmus. It is an invasive, systemic infection and can lead to colorectal fistulas and strictures if not treated early. Examination may reveal inguinal lymphadenopathy, genital ulcers, or rectal ulcers. Diagnosis is generally based on clinical suspicion and can be verified by NAAT. PCR-based genotyping can also be used to differentiate LGV from non-LGV chlamydia, but, in the absence of specific LGV diagnostic testing, those with a clinical syndrome suspicious for LGV should be treated. Treatment includes doxycycline 100 mg orally twice daily for 21 days. An alternative regimen is erythromycin base 500 mg orally 4 times a day for 21 days. Although treatment cures the infection, there may be resultant scarring from the tissue’s reaction to the infection.
Syphilis
Syphilis, caused by T pallidum , is a systemic disease that has been divided into a series of overlapping stages. Each year, the CDC estimates that approximately 55,000 people in the United States present with new syphilis infections. Of those diagnosed in 2011 (the most recent year with available statistics), 30% were in the earliest and most infectious stage of syphilis. Seventy-two percent of cases of primary and secondary syphilis were diagnosed in MSM. Transmission occurs by direct contact with an infectious lesion. The early lesions are very infectious, with an estimated transmission rate of one-third of patients exposed.
On average, it takes a week for symptoms to appear after infection, but it can take as long as 90 days. Initially 1 or multiple sores appear at the location where syphilis entered the body. Extragenital or anal chancres are generally painful and resolve after 3 to 6 weeks whether treated or not. Lymphadenopathy may be present. Weeks to a few months later, approximately one-quarter of untreated patients develop secondary syphilis, manifested as a systemic illness including rash, fevers, malaise, and diffuse lymphadenopathy. Secondary syphilis may also include mucous membrane lesions of the anus and rectum and proctitis. Condyloma lata, or large, raised, gray or white lesions may also develop in areas including the groin. Untreated, a patient goes into a latent stage without signs or symptoms. Fifteen percent of these patients develop late-stage syphilis, which can occur 10 to 30 years after the initial infection, and can develop paralysis, dementia, damage to multiple organs, and resultant death.
Syphilis is linked to HIV infection because the presence of open sores makes it easier to transmit and acquire. If exposed when syphilis sores are present, the risk of acquiring HIV is 2 to 5 times higher than if uninfected with syphilis.
In the past, diagnosis of syphilis was by visualization of the spirochete via darkfield microscopy; however, this is technologically difficult. Venereal disease research laboratory (VDRL) and rapid plasma reagin (RPR) (nontreponemal tests) are often used for screening because they are simple and inexpensive. They are not as specific for syphilis and, if reactive, the patient should undergo a treponemal test to confirm the diagnosis. Treponemal tests include fluorescent treponemal antibody absorption tests (FTA-ABS) and other immunoassays that detect antibodies that are specific for syphilis.
Syphilis generally responds well to curative treatment in its early stages. A single IM dose of 2.4 million units of benzathine penicillin G cures a person who has had syphilis for less than a year. For those with syphilis for longer than a year, additional doses are needed. For patients allergic to penicillin, the data are limited, but in nonpregnant patients doxycycline 100 mg orally twice daily for 14 days or tetracycline 500 mg 4 times daily for 14 days are acceptable alternatives. All patients with syphilis should undergo testing for HIV. For follow-up, clinical and serologic evaluation should occur at 6 and 12 months after treatment. Those with symptoms that persist or recur, or those with a nontreponemal titer that is 4 times baseline, should be considered treatment failures or to be reinfected. Repeat testing for HIV and treatment with benzathine penicillin G for 3 doses once a week is the treatment. Sexual partners should be deemed at risk and testing with presumptive treatment should be considered.
Donovanosis (Granuloma Inguinale)
Klebsiella granulomatis (formally known as Calymmatobacterium granulomatis ) is an intracellular bacterium that can cause ulcerative disease of the genitalia and anus. Although uncommon in the United States, it is endemic in some tropical and developing areas of the world. It manifests most commonly with genital ulcerative lesions, but they may also occur on the anus. The lesions are described as beefy red because of their vascularization, and bleed easily. Sclerotic lesions can develop on the anus and cause stenosis. Regional lymphadenopathy or subcutaneous granulomas (pseudobuboes) may also occur.
Testing for donovanosis is difficult because the organism is difficult to culture. Diagnosis requires visualization of dark-staining Donovan bodies on biopsy. Healing generally proceeds inward from the ulcer margins and prolonged therapy is usually necessary to permit reepithelialization of the ulcers. Even after apparently effective therapy, relapse can occur 6 to 18 months later. Recommended regimen by the CDC includes doxycycline 100 mg orally twice a day for at least 3 weeks and until all lesions have completely healed. Alternatives consist of azithromycin, ciprofloxacin, erythromycin, or trimethoprim-sulfamethoxazole. If improvement is not evident within the first few days of therapy, the addition of an aminoglycoside such as gentamicin should be considered.
Chancroid
Haemophilus ducreyi is the causative organism behind the ulcerating STD known as chancroid. It has become more and more infrequently reported in the United States, with only 24 cases in 2010 occurring in 9 states. Although this likely reflects a decline in incidence, it is also a difficult bacterium to culture, so it may be underdiagnosed. It is most common in parts of the Caribbean and Africa. The transmission is through breaks in the skin during sexual contacts. Hours to days after exposure, a person may develop a tender papule with erythema that goes on to develop into a pustule then an ulceration. In general, these are painful and, although most common on the genitalia, can occur in the perianal region.
As mentioned earlier, the test for chancroid is difficult and involves identifying H ducreyi . Gram stain may show gram-negative rods in small groups with a sensitivity of 40% to 60%. A special culture media, not widely available, is needed to attempt culture. With this, the sensitivity is still less than 80%. There are a few laboratories that offer PCR testing, but this is not widely available either.
For this reason, a probable diagnosis followed by treatment should be made based on the following criteria: presence of one or more painful genital ulcers; no evidence of T pallidum infection; regional lymphadenopathy that is typical of chancroid; and ulcer exudate that is negative for HSV.
Treatment is with azithromycin 1 g orally, ceftriaxone 250 mg IM once, ciprofloxacin 100 mg orally twice a day for 3 days, or erythromycin base 500 mg orally twice a day for 3 days. Successful treatment cures the infection, prevents transmission, and resolves the symptoms. In advanced cases, scarring can result. The patient should be reexamined in 3 to 7 days to ensure improvement.
HSV
Two types of HSV have been identified as causing genital herpes, HSV-1 and HSV-2. Herpes is a chronic, lifelong viral infection. HSV-2 is thought to cause most cases of recurrent genital herpes, but an increasing proportion of anogenital herpetic infections have been attributed to HSV-1. The CDC estimates that 776,000 people in the United States each year develop new herpes infections. One in 6 people aged 14 to 49 years have genital HSV-2 infection. Transmission is via anal, vaginal, or oral sex. The virus can be released from skin that does not appear to have a lesion.
Most people with HSV are asymptomatic or mistake the lesions for another skin condition. It is estimated that 81% of infected individuals are unaware of their diagnosis, which increases the rate of transmission because the infector is ignorant of the disease. Incubation period ranges from 2 to 12 days after exposure. Clinical manifestations include one or more vesicles on or near the anus, genitals, or mouth ( Fig. 1 ). These vesicles break and leave painful ulcers that may take several weeks to heal. The first outbreak is often associated with a longer duration of the lesions and may involve systemic symptoms such as fever, lymphadenopathy, or body aches. Recurrences are typically shorter in duration and less severe. The number of outbreaks tends to decrease over time and is less frequent among those with HSV-1 than for those with HSV-2. Acute HSV infection can also manifest as proctitis. HSV proctitis is suggested by the presence of severe anorectal pain, sacral parasthesias, diffuse ulceration of the distal rectal mucosa, and at times difficulty urinating. Nearly half of patients with HSV proctitis also get tender inguinal lymphadenopathy. It is acquired by anorectal intercourse and in homosexual men is second only to gonorrhea as a cause of proctitis.
