Multiple Cutaneous Abscesses Revealing Disseminated Nocardiosis in a Patient With Chronic Rheumatoid Arthritis

The patient was transferred from the dermatology department to the infectious diseases unit. Fiberoptic bronchoscopy with bronchoalveolar lavage and transbronchial biopsy confirmed pulmonary nocardiosis. Treatment with a combination of endovenous carbapenem and fluoroquinolone antibiotics for 1 month led to complete resolution of both the cutaneous lesions and the single brain abscess. Improvement of pulmonary involvement was noted on radiology, but another course of endovenous treatment with antibiotics was required, followed by oral amoxicillin–clavulanic acid (2 g daily) for 3 months. The patient underwent maintenance antibiotic therapy for 1 year without relapse and is considered to be cured.

Comment

Cutaneous nocardiosis occurs either as part of a disseminated infection or as a primary skin inoculation, usually following trauma or exposure from working outdoors.^2,9,21,22 Nocardial mycetoma, also known as actinomycetoma, is a chronic condition that mainly affects the lower extremities but also can affect the hands and forearms; it is frequently reported in tropical regions,²³ but disseminated forms are rare and undervalued, especially in European countries. A certain rise in incidence has been reported in Europe as a consequence of immune suppression, and pulmonary disease is the most common presentation in these patients.^1,2,6-12 One-third of patients have disseminated disease with high morbidity and a high mortality rate.²⁰ Major case collections in Italy have been studied by a collaborative hospital network of 11 cities,^10,11 confirming difficulty of diagnosis and underestimation, prevalence of N asteroides as a pathogen, resistance to several antimicrobials, and a high relapse index. Diagnosis remains challenging, as clinical suspicion is not frequently supported by histology and/or microbiology because of difficulty in bacteria isolation. Molecular methods are not routinely available in Italy, and only stringent efforts and cooperation from different university departments has allowed final identification of nocardiosis.

The sporotrichoid pattern of the lesions on the right leg was unique; it is considered the rarest presentation of cutaneous nocardiosis.²⁴ Our first suspicion was sporotrichosis, an infection that is especially common in farmers in Italy,^25,26 but the microbiologist’s evaluation of the bacterial pure cultures growing on skin specimens was negative for deep fungal infections. Further identification and confirmation by polymerase chain reaction assay of N asteroides required several weeks. Meanwhile, the chest radiograph followed by CT scans of the lungs and brain led to the diagnosis of a disseminated infection. Documentation of lung involvement 1 year prior to the development of the cutaneous lesions excluded primary cutaneous nocardiosis with secondary dissemination as reported in other immunocompromised patients, including those undergoing long-term treatment with corticosteroids.^15-19 Continuous follow-up and physician awareness of possible unusual infections is mandatory in patients undergoing immunosuppressive therapy. Our patient had a 20-year history of rheumatoid arthritis but was otherwise healthy with no signs of lung distress, fever, or general malaise. His only concern was leg impairment following acute development of painful lesions discharging pus over 1 month.

Conclusion

This case report highlights the role of the dermatologist as the first-line physician involved in the diagnosis of rare and potentially severe infections. Cooperation with the microbiologist, pathologist, and other internal medicine specialists is crucial; however, sometimes it is just the clinical suspicion and the perseverance of the dermatologist that ultimately leads to the correct diagnosis, which often is otherwise unspecific, undervalued, and misdiagnosed as more common diseases.