Sexually Transmissible Infections in Clinical Practice

18. A Gay Man with a Genital Ulcer

Alexander McMillan1, 2  


Department of Genitourinary Medicine, NHS Lothian, Edinburgh Royal Infirmary, Edinburgh, Uk


University of Edinburgh, Edinburgh, Uk

Alexander McMillanFormerly, Consultant Physician, part-time Senior Lecturer



James is a 22-year-old man who attends you as a Sexual Health physician. He tells you that he had noticed a sore on his penis for about 5 days, and that this sore is increasing in size. You know that he has sex with men because he had asked you to undertake an HIV antibody test a year before for visa purposes, and he told you then that he was a sexually active gay man. You arranged for hepatitis A and B vaccination at that time, and a Health Adviser provided advice on risk reduction for the sexually transmitted infections.

James is a 22-year-old man who attends you as a Sexual Health physician. He tells you that he had noticed a sore on his penis for about 5 days, and that this sore is increasing in size. You know that he has sex with men because he had asked you to undertake an HIV antibody test a year before for visa purposes, and he told you then that he was a sexually active gay man. You arranged for hepatitis A and B vaccination at that time, and a Health Adviser provided advice on risk reduction for the sexually transmitted infections.

18.1 What Further History Would You Wish to Elicit?

Specific enquiry should be made about the following:

·               Is the “sore” painful or tender?

·               Does it bleed easily?

·               Has he had similar lesions in the past?

·               Is there associated inguinal lymph node enlargement and if so, is uni- or bilateral, and are the enlarged glands painful or tender?

·               Does he have lesions elsewhere on his body?

·               What is his general health like?

·               Has he taken any prescribed or illicit drugs within the preceding month, and if so when were these used?

·               Has he had any sexually transmitted infections in the past?

The taking of a detailed sexual history is paramount (seeCase 4).

James tells you that the sore is somewhat tender but does not bleed; he has had some discomfort in the right groin that he attributes to a groin strain sustained while playing football. He has not previously noticed any genital lesions. His general health is good, and he has not been aware of any sores elsewhere on his body or of skin rashes. He has not used any prescribed medication for at least 5 years, but over the past 3 years he has taken ecstasy about twice monthly when he has been clubbing. He has not been treated for any sexually transmitted infections in the past. He completed the course of hepatitis A and B vaccination and had been shown to have had a good antibody response.

James does not have a regular partner, but he has had sex with eight different men in the preceding 3 months. Most men he has met through the Internet, and he is able to contact three of them if necessary. All his recent partners have lived in the United Kingdom. His most recent sexual contact had been 1 week previously just before the sore developed. He tells you that he has both receptive and penetrative anal intercourse and that condoms are used consistently for anal sex. Although he performs and receives fellatio, he rarely uses condoms for oral sex.

18.2 What Do You Do Next?

You perform a detailed examination of the anogenital region. It is convenient to begin the examination by inspection of the lower abdomen for rash that may indicate early secondary syphilis (in about a third of patients, the primary lesion of syphilis is still present). Palpate the inguinal lymph nodes. In primary syphilis (chancre), there is usually bilateral inguinal lymph node enlargement; the glands are discrete, rubbery, and unless the chancre is secondarily infected, non-tender. In primary genital herpes, there is usually uni- or bilateral tender enlargement of the inguinal lymph nodes. Lymphogranuloma venereum (caused by the lymphogranuloma venereum genotypes of Chlamydia trachomatis) and chancroid (caused by Haemophilus ducreyi) are associated with tender and, usually, unilateral inguinal lymph gland enlargement and abscess formation.

The external genitalia are then inspected. During the examination, you should note the following:

·               The anatomical site of the lesion or lesions.

·               Whether the ulceration is single or multiple. For example, the lesions of genital herpes and chancroid are usually multiple, but primary syphilis generally presents as a single ulcer.

·               Are the lesions tender, as may be found in genital herpes and chancroid?

·               Is the lesion indurated, as is the case in typical primary syphilis? Note that this feature is often absent in extragenital chancres, such as in the anal canal.

·               Does the lesion bleed easily? Chancroid is associated with multiple ulcers that bleed easily, whereas the primary lesion of syphilis tends not to bleed.

James has bilateral, non-tender inguinal lymph node enlargement. He has a single non-tender ulcer, measuring about 1 cm in diameter on the right side of the frenum (Fig18.1 ). It has a dull-red surface. When you palpate the lesion, you find that it is indurated 1 and that pressure produces serous exudate. There is no associated skin rash.


Figure 18.1.

Solitary parafrenal ulcer.

18.3 What Is the Most Likely Diagnosis?

The most likely diagnosis is primary syphilis. In recent years, there has been an increase in the incidence of early syphilis particularly among men who have sex with men, attending sexually transmitted infections clinics in the United Kingdom, continental Europe, Australia, and the United States. Although unprotected insertive and receptive anal intercourses are risk factors for acquisition of syphilis, in many cases the infection has been transmitted through unprotected oral–genital intercourse. Syphilis is caused by the spirochaete Treponema pallidum that is found in the fluid that exudes from the primary lesion or the moist mucosal or skin lesions of secondary syphilis (the dry skin lesions are not infectious). The organism invades the skin or mucous membrane where it initiates an inflammatory reaction in the dermis or submucosa that results in endarteritis with thrombosis and necrosis of the overlying epidermis or mucosal surface. Untreated, the primary lesion heals within 3–8 weeks. The primary lesion may be found on any part of the external genitalia, the uterine cervix, the anal canal, and the rectum. Lesions in the anal canal tend to be painful, tender, bleeding easily, and not indurated: thus in this anatomical site, primary syphilis resembles a traumatic anal fissure. Chancres may also occur on the lips, in the buccal cavity, tongue, tonsil, and pharynx.

18.4 How Would You Confirm the Diagnosis?

The diagnosis of primary syphilis can be made by dark field microscopy of the serum that exudes from the ulcer base. T. pallidum has a slender structure, with tight spirals and a characteristic motion.2Alternatively, T. pallidum can be detected by a polymerase chain reaction to detect specific DNA. Serological tests are used to confirm the diagnosis, but it should be borne in mind that in very early primary infection, the most commonly used screening tests – the treponemal enzyme immunoassay (EIA) or the Venereal Diseases Research Laboratory (VDRL) (or the Rapid Plasma Reagin test [RPR]) – may give negative results. It is therefore important to alert the laboratory that the patient may have primary syphilis so that more sensitive (but not routine) tests can be undertaken.

The serum from the ulcer on James’ penis failed to show T. pallidum. The serological results are as follows:

·               Screening EIA test: NEGATIVE

·               VDRL test: NEGATIVE

·               Treponema pallidum particle agglutination test (TPPA): POSITIVE (titer 1280)

·               Anti-treponemal IgM EIA: POSITIVE

These results confirm the clinical diagnosis.

18.5 What Is the Antimicrobial Agent of Choice, How Would You Administer It, and What Possible Reaction to Treatment Would You Warn Him of?

Table 18.1 shows the drug regimens used in the management of early infectious syphilis.

Table 18.1.

Drug regimens in the treatment of early syphilis.

Benzathine penicillin 2.4 MU in a single intramuscular dose, or repeated 7 days later


Procaine penicillin G 600–750 mg once daily by intramuscular injection for 10 days


Doxycyclinea 100 mg twice daily by mouth for 14 days


Erythromycina 500 mg four times daily by mouth for 14 days


aMay be used in patients with a history of penicillin hypersensitivity.

Penicillin is the treatment of choice. T. pallidum has not developed resistance to penicillin. The reason for prolonged treatment is that penicillin only acts on metabolically active organisms, and T. pallidum has a long generation time (30–33 h). James opts for benzathine penicillin.

You have ascertained from the history that James is not hypersensitive to penicillin; nevertheless it is useful to invite him to remain in the clinic for about 30 min to ensure that there is no hypersensitivity reaction to the drug. James, however, may develop the Jarisch–Herxheimer Reaction (JHR); just over half of patients with primary infection develop this reaction. In primary syphilis the effects are usually mild. The reaction develops within 4 h of starting treatment, becomes most intense at 6–8 h, and resolves within 24 h.

The clinical phases are the following:





The JHR that occurs only with the first injection of penicillin is probably the result of cytokine activation following release of endotoxin from the injured treponemes.

18.6 What Else Would You Do?

In the control of syphilis, partner notification is paramount. Because of the long pre-patent period, sexual partners over the preceding 3 months should be notified. Because of the strong association between syphilis and HIV, it is worthwhile discussing HIV antibody testing. There is good epidemiological evidence that syphilis is associated with an increased risk of transmission or acquisition of HIV. This evidence is supported by the observation that the virus can be detected in the serum that exudes from the ulcerated lesions of primary or secondary syphilis.

James should also be offered testing for other STIs (see Case 4).

James should be followed up clinically and with serological testing 3, 6, and 12 months after treatment to ensure cure. The VDRL test is likely to remain negative, the anti-treponemal IgM EIA will become negative, the titer in the TPPA may decrease, but it is probable that the test will remain positive, possibly for many years.

18.7 What Is the Natural History of Untreated Early Syphilis?

Untreated, a proportion of patients develops benign tertiary syphilis (gumma formation), neurological (general paralysis of the insane, tabes dorsalis, or a combination of these conditions – taboparesis), or cardiovascular disease: about 15, 10, and 8% respectively.

The risk of neurosyphilis is increased some four-fold in HIV-infected patients, particularly when the CD4+T-cell count is <350 per mL3.



Indurated = hard; sometimes likened to cartilage or a button under the skin. Note that induration is not an invariable finding.


The published sensitivity of dark field microscopy varies between 79 and 97%. Both the sensitivity and specificity are dependent on the experience of the microscopist. Because of interference from commensal spirochaetes that are found in the normal flora of the genital and rectal mucosa, DGM is considered to be less reliable in examining rectal and non-penile genital lesions. DGM is not suitable for examining oral lesions because of the many commensal treponemes that occur in the mouth. DGM can be applied to the moist mucous lesions (condylomata lata or mucous patches) of secondary syphilis but as serological tests are virtually 100% sensitive at this stage there is little need for it.

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