Clinical Scorecard: Disseminated Sporotrichosis Presenting as Tuberculosis in an Immunocompetent Patient: Challenges in Regions Endemic to Tuberculosis

At a Glance

Key Highlights

• Disseminated sporotrichosis can resemble tuberculosis and create diagnostic challenges, particularly in tuberculosis-endemic regions.

• Empirical treatment with isoniazid, rifampicin, pyrazinamide, and ethambutol did not improve the patient’s progressive lesions.

• Fungal culture grew pigmented colonies identified as Sporothrix schenckii complex after repeated staining failed to visualize organisms.

• Current guidelines cited by the authors recommend itraconazole as first-line therapy, with amphotericin B considered for induction in severe cases.

• A total treatment duration of at least 12 months is generally recommended for disseminated infection.

Guideline-Based Recommendations

Diagnosis

• Maintain a high index of suspicion for disseminated sporotrichosis when granulomatous disease resembles tuberculosis or other infections.

• Fungal culture is considered the diagnostic gold standard, although results may require 1 to 2 weeks.

Management

• Itraconazole is recommended as first-line therapy, while amphotericin B should be considered for induction in severe cases.

• At least 12 months of total therapy is generally recommended for disseminated sporotrichosis.

Monitoring & Follow-up

• In this case, intravenous antifungal therapy was continued until improvement was documented, after which treatment was transitioned to oral itraconazole.

• Follow-up included assessment of cutaneous lesions, respiratory symptoms, and CT findings. At 2 months, lesions had healed and pulmonary abnormalities had markedly improved; at 12 months, no active skin lesions or respiratory symptoms remained.

Risks

• Diagnostic bias toward tuberculosis may delay recognition of sporotrichosis in tuberculosis-endemic settings.

• Amphotericin B deoxycholate was associated with acute kidney injury in this patient, requiring a switch to liposomal amphotericin B.

Patient & Prescribing Data

The patient was a 78-year-old man with treated diffuse large B-cell lymphoma in complete remission for 10 years and no overt immunodeficiency identified on evaluation. He reported substantial contact with 16 stray cats, although infection in the cats was not microbiologically confirmed.

He initially received amphotericin B deoxycholate at 0.7 mg/kg/d but developed acute kidney injury after 4 days, prompting a switch to liposomal amphotericin B at 3 mg/kg/d for the remainder of a 14-day induction course. Treatment was then transitioned to oral itraconazole at 400 mg/d and continued for a total of 12 months.

Clinical Best Practices

• Broaden the differential diagnosis when disseminated granulomatous disease resembles tuberculosis, particularly in tuberculosis-endemic settings.

• Obtain a comprehensive exposure history, including possible animal contact, because identifying risk factors may help recognize sporotrichosis.

• For severe disseminated infection, the cited guidelines support amphotericin B induction followed by itraconazole, with treatment generally continued for at least 12 months.

Related Resources & Content

• Clinical Practice Guidelines for the Management of Sporotrichosis: 2007 Update by the Infectious Diseases Society of America — Kauffman CA, Bustamante B, Chapman SW, Pappas PG; Clinical Infectious Diseases; 2007; 45(10):1255-1265.

• Human Sporotrichosis: Recommendations From the Brazilian Society of Dermatology for the Clinical, Diagnostic and Therapeutic Management — Orofino-Costa R, Freitas DFS, Bernardes-Engemann AR, et al; Anais Brasileiros de Dermatologia; 2022; 97(6):757-777.

• Sporotrichosis: An Overview and Therapeutic Options — Mahajan VK; Dermatology Research and Practice; 2014; 2014:272376.

• Cutaneous Disseminated and Extracutaneous Sporotrichosis: Current Status of a Complex Disease — Bonifaz A, Tirado-Sanchez A; Journal of Fungi; 2017; 3(1):6.