Chancroid and Donovanosis

Overview

Genital ulcer diseases (with syphilis, herpes, LGV). Compare: pain, edge, base — narrows differential before labs.

Chancroid

Organism: Haemophilus ducreyi. Small fastidious Gram-negative coccobacillus. Gram stain: “SCHOOL OF FISH”/railroad track pattern (parallel chains/clusters) — distinctive, inconsistent.

Clinical: incubation 4-10d. PAINFUL, soft/non-indurated (“soft chancre” — contrast syphilis hard chancre) ragged-edge ulcer, grey-yellow friable bleeding base. PAINFUL unilateral inguinal LAD (substantial minority) → fluctuant suppurative bubo → ruptures = SINGLE draining sinus (contrast LGV’s MULTIPLE sinuses). Cofactor for HIV transmission (ulcerated bleeding lesion = exit+entry portal).

Diagnosis: CHALLENGING. Culture needs special media, poor sensitivity. No widely-used FDA NAAT. Often PRESUMPTIVE CLINICAL diagnosis after excluding syphilis (dark-field/serology) + HSV (PCR/culture).

Treatment: single-dose azithromycin or ceftriaxone (or multi-dose cipro/erythromycin). Fluctuant bubo: needle aspiration (I&D avoided, delayed healing risk).

Donovanosis (Granuloma Inguinale)

Organism: Klebsiella granulomatis (ex-Calymmatobacterium granulomatis). Intracellular Gram-negative. DIFFICULT to culture — real diagnostic limitation.

Clinical: slow progressive, PAINLESS, beefy-red ulcer, granulation-tissue base, BLEEDS EASILY on contact. (Distinctive combo: painless BUT bleeds — differs from syphilis chancre which doesn’t bleed this way.) LITTLE/NO regional LAD (unlike other genital ulcer diseases) — instead PSEUDOBUBOES (subcutaneous granulomatous extension mimicking LAD, NOT actual lymph node). Untreated: relentless progression, tissue destruction, disfiguring scarring/lymphedema (months-years). Rare: malignant transformation (SCC) in very long-standing lesion.

Diagnosis: culture impractical. DIRECT MICROSCOPY (tissue smear/biopsy) — DONOVAN BODIES: dark-staining intracellular encapsulated rods within large mononuclear cells, “CLOSED SAFETY PIN” appearance (bipolar staining). Wright/Giemsa stain, essentially diagnostic.

Treatment: PROLONGED — azithromycin/doxycycline/co-trimoxazole, MINIMUM 3 weeks, continue until FULL re-epithelialization. Shorter course risks relapse.

Comparison Table

Two Genital Ulcer Diseases

Chancroid and donovanosis are two of the classic “genital ulcer disease” causes taught together with syphilis, herpes, and lymphogranuloma venereum — the useful organizing exercise across all of them is comparing the ulcer’s pain, edge, and base, since these bedside features narrow the differential meaningfully before any laboratory result returns.

Chancroid

The Organism

Haemophilus ducreyi is a small, fastidious, Gram-negative coccobacillus, related to (but genitally distinct in disease from) the respiratory Haemophilus species. On Gram stain of ulcer material it characteristically shows organisms arranged in parallel chains or clusters described as a “school of fish” or “railroad track” pattern — a distinctive, if inconsistently seen, morphological clue.

Clinical Manifestations

After a short incubation (typically 4–10 days), chancroid produces one or more painful, soft (non-indurated — hence the name “soft chancre,” in deliberate contrast to syphilis’s hard/indurated chancre), ragged-edged genital ulcers with a base classically covered in grey-yellow, friable, easily bleeding exudate. Painful, unilateral inguinal lymphadenopathy develops in a substantial minority, which can progress to a fluctuant, suppurative bubo — and, if this bubo ruptures spontaneously, it forms a single draining sinus, a distinctive point of contrast with the multiple draining sinuses characteristic of lymphogranuloma venereum’s suppurative lymphadenopathy. Chancroid is also epidemiologically significant as a genuine cofactor for HIV transmission, since the ulcerated, bleeding lesion provides both an exit and entry portal for the virus during sexual contact.

Laboratory Diagnosis

Diagnosis is genuinely challenging, since H. ducreyi culture requires special enriched media and has poor sensitivity even under ideal conditions, and no FDA-cleared NAAT is in wide routine use in most settings — meaning chancroid is frequently diagnosed presumptively, on clinical grounds, after excluding syphilis and HSV (by dark-field/serology and PCR/culture respectively) in a patient with a compatible painful ulcer, rather than by direct laboratory confirmation.

Treatment

Single-dose azithromycin or ceftriaxone (or a multi-dose course of ciprofloxacin or erythromycin) are effective; fluctuant buboes may need needle aspiration for symptomatic relief, though incision and drainage is generally avoided given delayed healing risk.

Donovanosis (Granuloma Inguinale)

The Organism

Klebsiella granulomatis (formerly classified as Calymmatobacterium granulomatis) is an intracellular Gram-negative bacterium, genuinely difficult to culture on standard media — a real diagnostic limitation, since it means the organism’s own growth cannot serve as the routine confirmatory test the way it does for many other bacterial STIs.

Clinical Manifestations

Donovanosis produces a slowly progressive, painless, beefy-red ulcer with a granulation-tissue-like, friable, easily bleeding base that bleeds readily on contact — a genuinely distinctive combination (painless yet notably bleeds easily) worth holding onto, since the painlessness alone would suggest syphilis, but syphilis’s chancre does not characteristically bleed this way. Unlike the other genital ulcer diseases, donovanosis characteristically causes little to no regional lymphadenopathy — instead, subcutaneous spread near the groin can produce pseudobuboes (a swelling that mimics true lymphadenopathy but is actually granulomatous extension of the primary lesion itself, not a lymph node at all). Untreated, the disease is slowly and relentlessly progressive, causing extensive tissue destruction and disfiguring genital scarring/lymphoedema over months to years, and, rarely, can undergo malignant transformation to squamous cell carcinoma within a very long-standing lesion.

Laboratory Diagnosis

Because culture is impractical, diagnosis rests on direct microscopy of a tissue smear or biopsy, demonstrating Donovan bodies — the organism visible as characteristic dark-staining, intracellular, encapsulated rod-shaped bacteria within large mononuclear cells, described as resembling a “closed safety pin” from the appearance of the bipolar-staining bacterial body — a distinctive, essentially diagnostic finding on Wright or Giemsa stain of crushed tissue.

Treatment

Prolonged therapy — azithromycin, doxycycline, or co-trimoxazole for a minimum of three weeks, and continued until the lesion has fully re-epithelialized — reflecting the disease’s genuinely slow, indolent natural course; a shorter course risks incomplete clearance and relapse.

Quick Comparison

Short Notes (1)

Multiple Choice Questions (1)