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Sexually transmitted infections (STIs) often present with mucocutaneous symptoms and signs in the anogenital region and as such, the management has traditionally been provided by dermatologists. This specialty which is termed venereology has continued to be practised by dermatologists in Europe and Asia in comparison to other countries such as Australia and the UK where it has evolved into a specialty on its own.

STIs are endemic worldwide and continue to be a major public health concern in particular because they have been shown to increase the transmission as well as the acquisition of HIV infection. Asia and the Western Pacific region combined have been shown to house the largest numbers of curable bacterial STIs of all the global regions. The relative ease and affordability of international as well as domestic travel enables the rapid transmission of STIs. Cultural and religious influences unique to individual countries in Asia may sometimes propagate STI transmissions. They range from social taboos to misconceptions about STIs and misguided sexual health campaigns to poorly developed sex education programs in schools, all of which can lead to unsafe sexual practices and poor sexual healthseeking behaviors. As a consequence, there continues to be a concerted effort by international as well as regional organizations, working closely with local health authorities to promote safer sex practices to stop the spread of STIs and HIV infection in Asia.

A number of dermatological conditions can present in the anogenital region alone, or in association with lesions on other parts of the body. The presence of cutaneous pathologies occurring on the genitalia often provokes a reflex association with STIs. Dermatologists, by virtue of their training, are equipped to make the distinction between STIs and non-STI genital dermatoses, and provide reassurance to patients. The clinical presentation of STIs helps direct the physician on the appropriate microbiological investigations that are needed to confirm the diagnosis prior to definitive treatment.

The initial section of this chapter covers the STIs, while the next section covers the non-STI genital dermatoses. Skin disorders in HIV-infected persons are covered in Chapter 26.


STIs can be broadly categorized into several main groups based on their clinical presentation. They include genital ulcers, discharges, growths, and parasitic skin infestations.

Genital Ulcers

Syphilis (chancre of primary syphilis) and genital herpes are the two most significant ulcerative STIs and may be indistinguishable clinically (Figures 25–1, 25–2, 25–3, 25–4, 25–5, 25–6, 25–7, 25–8, 25–9, 25–10, 25–11, 25–12, 25–13, 25–14, 25–15, 25–16, 25–17, 25–18, 25–19, 25–20, 25–21).

Figure 25-1

Primary syphilis—penile chancre

The primary stage of syphilis is characterized by the appearance of an indurated and painless, typically solitary, ulcer on the genitalia known ...

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