Most sexually transmitted genital ulcers in the UK are caused by Herpes simplex virus (HPA, 2005). Treponema pallidum is another common cause. Dark-ground microscopy, serological testing for syphilis and Herpes simplex culture can be performed to aid diagnosis. Nucleic acid amplification tests are also available for both organisms. Other sexually transmitted infective causes such as lymphogranuloma venereum, Haemophilus ducreyi and donovanosis should be considered, and a good travel history of both the patient and their partners is helpful. Other non-infective causes of genital ulcer disease include Behcet's disease and Crohn's disease.
Herpes simplex virus typically presents as multiple painful vesicles or pustules, which break down to form erosive ulcers. These are generally painful and may coalesce to form larger areas of painful ulceration. True primary episodes are generally more severe than subsequent episodes, and are often associated with systemic symptoms. Many people, however, are unaware they are infected, as they do not experience symptoms. Asymptomatic shedding of Herpes simplex virus has been shown to occur and is probably an important means of trans-mission.An understanding of asymptomatic shedding can facilitate acceptance of what may become a chronic recurring condition. Differential diagnoses include primary syphilis, candidiasis, contact dermatitis and fixed drug reaction.
The ulcer of primary syphilis (chancre) occurs 14 to 21 days following exposure. A painless papule appears at the site of inoculation. This grows to 0.5 to 1.5cm, ulcerates and becomes a chancre (Musher, cited in Holmes, 1999). The chancre of primary syphilis is typically a single, painless ulcer with an indurated margin and a clean base. However, they may also be multiple, painful, purulent and destructive (BASHH, 2002). They occur typically in the genital, perineal or anal area and are associated with inguinal lym-phadenopathy. Any part of the body can, however, be affected, and oral lesions are not uncommon if oral sex has occurred.
Genital lesions are typically seen on the penis of men and the labia, fourchette or cervix of women. Chancres of the anus or rectum also occur. Thorough sexual history-taking will lead to appropriate physical examination and subsequent observation of lesions. Dark-ground microscopy can be performed to visualise Treponema pallidum, though this should not be attempted from oral lesions to avoid confusion with a similar non-pathogenic organism that may be found in the mouth. Syphilis serology should be performed and repeated at three months if negative.
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