STDs (Anogenital Leisions)

• DDx: Anogenital lesions

  Viral:

  • Genital warts.
  • Genital herpes.
  • Molluscum contagiosum.

  Bacterial:

  • Syphilis
  • Tropical STIs: lymphogranuloma, chancroid.

  Others:

  • Scabies
  • Trauma
  • Cancer

• Genital warts

  Aka condyloma acuminata.

  Pathogen

  Usually human papillomavirus (HPV) 6 or 11.

  Signs and symptoms

  • Painless, often multiple warts.
  • May be internal: cervix, anus.

  Investigations

  Clinical diagnosis. Biopsy only if there is doubt.

  Management

  Topical therapy options:

  • Podophyllotoxin cream (self-applied).
  • Imiquimod (self-applied).
  • Trichloroacetic acid.

  Other options:

  • Cryotherapy
  • Surgical excision.

  Complications

  Squamous cell carcinoma: cervical or anal.

• Genital herpes

  Pathogen

  Herpes simplex infection: HSV2 (commoner) or HSV1.

  Presentation

  Time course and transmission:

  • The typical pattern is a primary infection followed by a chronic latent infection – with the virus lying dormant in ganglion cells – with intermittent reactivation.
  • Both primary infections and reactivations are often asymptomatic, but patients will be infectious during these periods. Subsequently, the virus is often transmitted by people unaware that they are infected.
  • 3-7 days incubation from exposure until primary infection, but individuals may not have their first symptomatic episode until years after first infection. This can cause confusion and distress in long-term relationships.

  Symptomatic primary infection:

  • Flu-like prodrome.
  • Vesicular lesions, with then burst and heal within 3 weeks.
  • Discharge and dysuria. Urinary retention may result from the dysuria.
  • Tenesmus
  • Tender inguinal lymphadenopathy.

  Symptomatic recurrences are usually milder, affecting one site and healing within 10 days.

  Investigations

  • Viral culture or DNA PCR (swab from base of ulcer).
  • Serology +ve week-months later: useful in hard to diagnose recurrent infection, or for asymptomatic partners.

  Management

  • 1st episode: aciclovir PO 5 days, analgesia (oral analgesia or topical lidocaine gel).
  • Recurrent: continuous aciclovir if severe or >6 episodes/year.
  • Preventing transmission to a new partner: use condoms, especially in the 12 months after the 1st attack. Long-term aciclovir or valaciclovir by the infected partner also reduces transmission.
  • In pregnancy, treat all episodes with aciclovir PO. Women with acquisition in 1st or 2nd trimester or recurrent herpes should then be offered daily suppressive treatment with aciclovir from 36 weeks, which should allow safe vaginal delivery. Women with acquisition in 3rd trimester should remain on aciclovir until delivery, which should be by C-section.

  Complications

  • Neurological: meningitis, encephalitis (HSV1), neuralgia.
  • Neonatal herpes: skin, eye, and mouth, or CNS.
  • HSV2 increases the risk of HIV infection.

• Syphilis

  Pathophysiology and epidemiology

  • Infection with the spirochete Treponema pallidum.
  • Most cases are in men who have sex with men.
  • 9-90 day incubation, usually 2-3 weeks.

  Signs and symptoms

  Primary syphilis:

  • Chancre: painless hard ulcer at infection site.
  • Inguinal lymphadenopathy.
  • Only the chancre site itself is infective.

  Secondary syphilis:

  • Occurs 6 weeks to 6 months after primary infection.
  • Rash: generalised and including the palms and soles.
  • Fever, headache, my/arthralgia.
  • Condylomata lata: highly-infectious wart-like lesions on genitals.
  • Resolves in 3-6 weeks.
  • Neurosyphilis generally only occurs at this stage if immunosuppressed.

  Tertiary syphilis:

  • Occurs 1-30 years after primary infection.
  • Gummatous syphilis: granulomas in bone and cartilage. May lead to saddle nose.
  • Neurosyphilis: dementia, tabes dorsalis (dorsal column loss).
  • Cardiovascular: vasculitis, stroke, aortitis and mycotic aneurysms.

  Latent phase:

  • Early: asymptomatic, <1 years from primary infection, may be infectious
  • Late: asymptomatic, >1 years from primary infection, not infectious.

  Investigations

  • Diagnosis usually with treponemal serology tests: enzyme immunoassay (EIA) IgM and IgG, with confirmatory T. pallidum particle agglutination (TPPA) test if +ve.
  • Non-treponemal tests – quantitative VDRL or rapid plasmin reagin (RPR) – then performed to determine stage and titre (i.e. disease activity).
  • Direct testing for the organism from mucosal swabs – e.g. dark field microscopy or PCR – can also be done but is not always available.
  • Lumbar puncture if there are neuro signs, to check CSF-VDRL and cell count.

  Management

  • Primary, secondary, and early latent: benzylpenicillin IM single dose. 2nd line azithromycin PO single dose, or doxycycline PO for 2 weeks.
  • Late latent: benzylpenicillin IM weekly for 3 weeks. 2nd line doxycycline PO for 4 weeks.
  • Neurosyphilis: procaine penicillin IM plus probenicid PO for 17 days. 2nd line doxycycline PO for 4 weeks.

  Congenital infection

  • Hepatosplenomegaly.
  • Neurological deficits.
  • Saddle nose.
  • Joint and bone disease.