What is the likely diagnosis, appropriate work‑up, and treatment for a circular ulcer with a dark‑red rim on the labia in a woman, especially if she has traveled to Leishmania‑endemic areas?

Cutaneous Leishmaniasis of the Labia: Diagnosis and Management

A circular ulcer with a dark-red rim on the labia in a woman with travel to Leishmania-endemic areas is highly suggestive of cutaneous leishmaniasis and requires tissue diagnosis through full-thickness punch biopsy from the indurated border, followed by multiple diagnostic modalities including microscopy, culture, and molecular testing. 1

Clinical Diagnosis

The presentation is characteristic of cutaneous leishmaniasis (CL) based on several key features:

• Lesion morphology: Well-defined, indurated borders with ulceration and chronicity are typical of CL 1
• Location: While genital lesions are rare, they have been documented and follow the same diagnostic principles as lesions elsewhere 2
• Painless nature: CL lesions are typically painless unless secondarily infected or over a joint 1
• Endemic exposure: Travel history to Leishmania-endemic areas (Americas, Middle East, North Africa, Asia) is essential context 1, 3

The incubation period is usually several weeks, with lesions beginning as papules that progress and often ulcerate 1. The dark-red rim suggests an active, indurated border where parasites are most likely to be found 1.

Diagnostic Work-Up

Specimen Collection

Obtain a full-thickness punch biopsy from the indurated edge of the lesion after thorough cleansing to remove cellular debris and exudates. 1

Critical technical points:

• Avoid epinephrine in local anesthesia for genital lesions (use lidocaine alone) 1
• Sample from the active-appearing indurated border, not the ulcer center, where histology shows fewer degradation changes 1
• Use sterile technique and avoid leaving residual iodine or alcohol that may interfere with culture 1
• The biopsy allows simultaneous testing for other diagnoses and multiple Leishmania detection methods 1

Laboratory Testing Strategy

Use multiple diagnostic approaches simultaneously to maximize detection: 1

1. Microscopy: Giemsa-stained tissue impression smears or scrapings to visualize amastigotes within macrophages 1

2. Molecular testing: PCR is the most sensitive test currently available and should be performed 1

3. Culture: Attempt parasite isolation in specialized media (NNN medium) for species identification through isoenzyme analysis or DNA-based assays 1, 2

4. Histopathology: Examine tissue sections for granulomatous infiltrate and amastigotes 2

5. Rapid point-of-care testing: The FDA-cleared CL Detect immunochromatographic assay can be used on tissue brushings from ulcerative lesions 1

Contact a leishmaniasis reference laboratory before collecting specimens for guidance on specimen handling and transport 1.

Species Identification Importance

Determining the specific Leishmania species is critical because:

• New World Viannia species (particularly L. braziliensis) carry substantial risk for mucosal leishmaniasis (ML), especially if acquired in the "mucosal belt" of Bolivia, Peru, and Brazil 1
• Species identification guides treatment decisions and monitoring requirements 1
• Genital lesions caused by L. (V.) braziliensis may be followed by mucosal involvement of nasal cavity and palate 2

Treatment Considerations

Critical Assessment for Mucosal Risk

All patients must be questioned and examined for mucosal symptoms and signs, even during initial evaluation, particularly if infected with Viannia species. 1

Examine the naso-oropharyngeal mucosa thoroughly for:

• Chronic nasal congestion or secretions
• Erythema, edema, infiltration, nodules, erosion, or ulceration 1

Treatment Approach Based on Complexity

Local therapy alone is NOT recommended for genital lesions due to:

• Genital location is specifically listed as a contraindication for local therapy (heat, cryotherapy, intralesional antimony) 1
• Risk of vascular compromise in this anatomically sensitive area 1
• Potential for New World species with mucosal dissemination risk 1

Systemic therapy is indicated because genital location represents "complex CL" requiring parenteral or oral treatment 1.

The treatment mainstay is pentavalent antimony (sodium stibogluconate), with alternatives including amphotericin B, pentamidine, paromomycin, and antifungals 3. Treatment duration is typically 10 mg/kg/day for 30 days for pentavalent antimony 2.

Common Pitfalls to Avoid

• Do not use epinephrine-containing local anesthesia on genital lesions during biopsy 1
• Do not rely on single diagnostic method: Use multiple approaches simultaneously as sensitivity varies 1
• Do not assume absence of mucosal disease: ML can develop without history of symptomatic cutaneous infection 1
• Do not use local therapy alone for genital lesions regardless of size 1
• Do not skip species identification: This determines mucosal risk and monitoring requirements 1

Long-Term Monitoring

Patients at risk for ML (based on species and geographic acquisition) require:

• Explicit questioning about persistent naso-oropharyngeal/laryngeal symptoms at all follow-up visits 1
• Thorough examination of naso-oropharyngeal mucosa even without symptoms 1
• Patient education about seeking immediate attention for persistent, atypical mucosal manifestations 1
• Monitoring for 6-12 months after exposure for development of new lesions or systemic symptoms 4