STI Clinical Hints


Male urethritis

  • Treat empirically. Don’t wait for results.
  • Use doxycycline 100 mg bd for 7 days. Add ceftriaxone 500 mg stat, dissolved in 2 ml 1% lignocaine,, together with I g oral azithromycin only if gonorrhoea (TG) is suspected ie thick, purulent discharge.
  • Consider herpes (TG) or adenoviral urethritis (TG) when dysuria is severe.

Vaginitis and vaginal discharge

  • Candidiasis  and Trichomoniasis (TG) are almost always associated with vulvar itching and/or irritation.
  • Exclude a retained tampon or other foreign body in cases of malodorous discharge.
  • Think of herpes in cases of vulvitis with inguinal lymphadenitis. Candidiasis is unlikely to be associated with regional lymph node inflammation.


Sexual health screening

  • A syphilis epidemic is occurring in gay men and heterosexual males and females in Victoria
  • Congenital syphilis cases have occurred in Victoria: all antenatal women should be screened for syphilis
  • Blood tests alone are inadequate for STI screening.
  • A first-void urine sample (men and women) or high vaginal swab (women) should always be sent for chlamydial and gonococcal testing.
  • A first-void urine sample does not have to be the first urine of the day.
  • Never order an HIV test without accompanying syphilis serology
  • Gay men should have a throat and anal swabs for gonococci and chlamydia.
  • Hepatitis C serology is unnecessary, except in injecting drug users and HIV positive men.
  • Tests for Ureaplasma urealyticum and Mycoplasma (TG) hominis should NOT be performed.
  • When ordering Hepatitis B serology, there is no point ordering just HBsAg unless the patient is jaundiced or acute viral hepatitis is suspected.
  • If ordering Hepatitis B serology to determine immunity, order anti-HBc and anti-HBs. If anti-HBc is reactive and Anti-HBs is negative, then ask the lab to do HBsAg
  • In interpreting syphilis serology, the TPPA is a reliable indicator of exposure to syphilis.
  • Any person with a reactive TPPA and no convincing history of treatment should be treated for syphilis.
  • Syphilis should be treated with benzathine penicillin – not other forms of penicillin.
  • Avoid herpes serology as a screening test, and be careful when interpreting results. HSV EIA serology is prone to frequent false positives and negatives.

Genital ulceration

  • In any painful breach of the genital skin, consider genital herpes.
  • Most first presentations of herpes are recurrences of prior asymptomatic infection, rather than being recently acquired.
  • A negative swab for PCR does not exclude a diagnosis of herpes, especially if the lesions are more than a few days old.
  • Herpes does not prevent normal vaginal delivery.
  • Kenacomb ointment should be avoided on the genitals. It may prolong herpetic ulceration and may cause contact dermatitis.

Genital lumps

  • Do not confuse normal anatomical variants for genital warts.Such normal findings include pearly penile papules, Tyson's glands, vestibular papillae and sebaceous glands (Fordyce spots).
  • Warts typically have a verrucous surface, and tend to be centrally distributed in the anogenital region.
  • Molluscum contagiosum lesions are smooth, round and centrally umbilicated. They tend to be distributed more peripherally than warts, on buttocks, thighs and pubic area.
  • Warts (TG) do not cause cancer. 
  • Topical treatments work best on non-keratinized warts.