Chancroid and Other Genital Ulcers

Chancroid - Ducreyi's Painful Dagger

• Causative Agent: Haemophilus ducreyi (Gram-negative coccobacillus).
  • Microscopy: "School of fish" or "railroad track" appearance.
• Clinical Features: 📌 'Ducreyi makes you cry' (painful).
  • Ulcer: Painful, soft, non-indurated, ragged/undermined edges. Base often has grey/yellow exudate.
  • Bubo: Tender, unilateral, suppurative inguinal lymphadenopathy (bubo) in ~50% cases; may rupture.
• Diagnosis:
  • Primarily clinical + exclusion of other causes (syphilis, HSV).
  • Definitive: Culture (special media, difficult) or NAAT/PCR (most sensitive & specific).
  • Gram stain: Low sensitivity.
• Treatment (Single Dose Regimens Preferred):
  • Azithromycin 1g PO single dose.
  • Ceftriaxone 250mg IM single dose.
  • Alternatives: Ciprofloxacin, Erythromycin.

⭐ Co-infection with HIV is common, and chancroid ulcers facilitate HIV transmission.

Syphilitic Chancre - Treponema's Tricky Ulcer

• Organism: Treponema pallidum (spirochete).
• Clinical Features:
  • Typically single, painless, indurated ulcer ("Hunterian chancre") with clean base, raised firm (cartilaginous) borders.
  • Bilateral non-tender, rubbery lymphadenopathy.
  • Incubation: 9-90 days (average 3 weeks).
• Diagnosis:
  • Dark-field microscopy: Gold standard from lesion exudate (shows motile spirochetes).
  • Serology:
    • Non-treponemal (VDRL/RPR): May be negative in early primary syphilis.
    • Treponemal (FTA-ABS/TPPA): More specific, confirm reactivity.
• Treatment:
  • Benzathine Penicillin G 2.4 million units IM single dose.
  • 📌 Mnemonic: T. pallidum = Painless primary ulcer. Penicillin G is the cure.

⭐ A syphilitic chancre is highly infectious, even if painless.

Genital Herpes - Vexing Viral Vesicles

• Etiology & Presentation: Caused by Herpes Simplex Virus (HSV), predominantly HSV-2 > HSV-1. Characterized by multiple, painful vesicles on an erythematous base, progressing to shallow ulcers. Associated with dysuria and tender inguinal adenopathy. Recurrences are common, often heralded by a prodrome (e.g., tingling, burning).
• Diagnosis:
  • Primarily clinical.
  • Confirmation: Viral culture (from active lesions), PCR (most sensitive).
  • Supportive: Tzanck smear (reveals multinucleated giant cells; supportive, not specific).
• Management: Antivirals like Acyclovir, Valacyclovir, Famciclovir for episodic or suppressive therapy.
  • First episode: e.g., Acyclovir 400mg TID for 7-10 days.

⭐ Most genital herpes infections are transmitted by individuals unaware they have the infection or who are asymptomatic at the time of transmission.

Rare Rivals - LGV & Donovanosis

High‑Yield Points - ⚡ Biggest Takeaways

• Chancroid (H. ducreyi): Painful ulcer, suppurative buboes; "school of fish" microscopy. Rx: Azithromycin.
• Syphilis (T. pallidum): Painless, indurated chancre. Rx: Penicillin G.
• Genital Herpes (HSV): Painful vesicles then ulcers; recurrent. Rx: Acyclovir.
• LGV (C. trachomatis L1-L3): Transient ulcer, painful lymphadenopathy ("groove sign"). Rx: Doxycycline.
• Granuloma Inguinale (K. granulomatis): Painless, progressive, beefy-red ulcer; Donovan bodies. Rx: Azithromycin.
• Pain differentiates: Chancroid/Herpes (painful); Syphilis/LGV/Donovanosis (painless).
• Always test for HIV co-infection.