A 49-Year-Old Male with Progressive, Non-Healing Cutaneous Ulcers

Case at a Glance

A 49-year-old male presented with a two-month history of three progressively worsening cutaneous lesions on his body. What initially appeared as simple boils evolved into deep, painful, and exudative ulcers. The lesions failed to respond to multiple courses of empirical oral and topical antibiotics, prompting an extensive diagnostic workup that revealed a complex anaerobic infection, though the definitive diagnosis remained elusive.

Patient's Story

The patient, a 49-year-old male, was in his usual state of health until late April when he developed three skin lesions that resembled boils or severe folliculitis. He and his spouse initially managed these at home with over-the-counter antiseptics, including chlorhexidine gluconate, hydrogen peroxide, and alcohol. Instead of resolving, the lesions worsened over several weeks, eroding into deep, painful ulcers that continuously oozed serosanguinous fluid, causing significant distress and impacting his quality of life.

Initial Assessment

The patient first sought medical attention from his primary care physician (PCP) approximately one month after the initial onset. The working diagnosis was a bacterial skin and soft tissue infection. Given the appearance of the lesions, an empirical treatment approach was initiated. The patient was prescribed a 7-day course of doxycycline hyclate. When this failed to produce any improvement, he was subsequently prescribed topical mupirocin for 10 days, which also proved ineffective.

The Diagnostic Journey

With the patient's condition deteriorating, the diagnostic approach was escalated. A third visit to the PCP in early June led to a broader antibiotic regimen of doxycycline monohydrate and cephalexin, both for 10 days. A standard wound culture was performed, which surprisingly returned with no growth.

Due to the lack of response and the negative culture, further investigations were ordered during a fourth visit. While awaiting results, the patient was started on amoxicillin-clavulanate. A fungal culture came back negative. However, a specialized deep/non-healing wound panel using advanced techniques identified a polymicrobial anaerobic infection, detecting Peptostreptococcus anaerobius, Peptoniphilus asaccharolyticus, Finegoldia magna, and Anaerococcus prevotii.

Following these results, the patient was referred to a dermatologist and started on metronidazole to target the anaerobic bacteria. The dermatologist, upon initial examination, expressed uncertainty regarding the underlying etiology. She recommended applying a non-prescription polysporin ointment and scheduled a follow-up for a skin biopsy for histopathological examination. At the time of this report, the patient had been on metronidazole for five days with no discernible clinical improvement, and the ulcers remained painful and exudative.

Final Diagnosis

Pending. The current evidence points to a complex polymicrobial anaerobic cutaneous infection. However, the failure to respond to appropriate anaerobic coverage (metronidazole) and the atypical presentation raise suspicion for an underlying inflammatory, vasculitic, or malignant process. A definitive diagnosis is contingent upon the results of the planned skin biopsy.

Differential diagnoses include:

• Pyoderma Gangrenosum (which can be secondarily infected)
• Atypical mycobacterial or deep fungal infection (despite negative initial cultures)
• Cutaneous vasculitis
• Cutaneous malignancy (e.g., squamous cell carcinoma)

Treatment Plan

The immediate treatment plan focuses on both antimicrobial therapy and obtaining a definitive tissue diagnosis.

1. Antimicrobial Therapy: Continue the course of metronidazole as prescribed, pending further clinical evaluation.
2. Wound Care: The use of Polysporin was deemed insufficient. Expert consultation suggested a need for proper wound care, potentially involving debridement and specialized dressings under the guidance of a wound care specialist.
3. Diagnostic Plan: The most critical next step is the scheduled skin biopsy. This procedure is essential to obtain tissue for histopathology and potentially for specialized tissue cultures (e.g., for mycobacteria and fungi) to rule out other underlying causes.

Outcome and Follow-up

The patient's condition remains unresolved, with persistent symptoms causing significant morbidity. The clinical course highlights a challenging diagnostic dilemma where initial empirical treatments were ineffective. The key recommendation from consulting physicians was to proceed urgently with the biopsy to guide further management. A referral to a dedicated wound care specialist was also strongly advised to optimize local wound management, control exudate, manage pain, and prevent further tissue damage while the diagnostic process continues.