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A case report of disseminated histoplasmosis not responding to primary treatment by itraconazole

Summary

A healthy 28-year-old woman developed a serious fungal infection caused by Histoplasma capsulatum after dental surgery. The standard antifungal medication (itraconazole) did not work for her, even at high doses. Doctors successfully treated her with a more powerful antifungal drug called liposomal amphotericin B, which cleared the infection completely. This case shows the importance of adjusting treatment when patients don’t respond to initial therapy.

Background

Histoplasmosis, caused by Histoplasma capsulatum, is a systemic fungal infection that typically presents as pulmonary infection but can disseminate. Oral lesions occur in 25-45% of immunocompromised individuals but are rare in immunocompetent patients. Standard treatment includes itraconazole for mild cases and liposomal amphotericin B for severe forms.

Objective

To report a case of disseminated histoplasmosis in an immunocompetent 28-year-old female patient that failed to respond to itraconazole therapy and required alternative treatment.

Results

Despite itraconazole therapy at doses up to 600 mg daily, the patient’s condition deteriorated with disease progression on imaging and elevated urinary Histoplasma antigen levels. Switching to liposomal amphotericin B (200 mg IV daily for 6 weeks) resulted in marked clinical improvement, resolution of lung nodules, and negative antigen testing.

Conclusion

This case highlights the importance of recognizing disseminated histoplasmosis in immunocompetent patients and timely adjustment of treatment when inadequate response to itraconazole occurs. Individualized treatment plans and access to therapeutic drug monitoring are essential for better patient outcomes in refractory cases.
  • Published in:Current Medical Mycology,
  • Study Type:Case Report,
  • Source: PMID: 41122116; DOI: 10.22034/cmm.2025.345248.1613
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