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

Summary

A 28-year-old woman developed a serious fungal infection (histoplasmosis) after dental surgery that was initially misdiagnosed as a bacterial infection. Although she was treated with an antifungal medication called itraconazole, her condition worsened with larger lung lesions appearing. When switched to a stronger intravenous antifungal called liposomal amphotericin B, she rapidly improved and fully recovered, demonstrating the importance of adjusting treatment when patients don’t respond as expected.

Background

Histoplasmosis, caused by Histoplasma capsulatum, typically presents as pulmonary infection but can disseminate with oral lesions common in immunocompromised individuals. Disseminated histoplasmosis with oral lesions is rare in immunocompetent patients. Preferred treatments include 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 that developed following dental surgery and initially misdiagnosed as actinomycosis. The case highlights treatment failure with itraconazole despite dose optimization and successful response to liposomal amphotericin B.

Results

Despite itraconazole therapy at doses up to 600 mg daily with therapeutic drug levels, the patient’s condition deteriorated with disease progression on imaging. Switching to intravenous liposomal amphotericin B 200 mg daily for 6 weeks led to marked improvement, resolution of lung nodules, and negative antigen testing. The patient achieved full recovery with 12-month itraconazole maintenance therapy.

Conclusion

This case emphasizes the importance of timely recognition of histoplasmosis in immunocompetent individuals and the need for treatment adjustment in cases not responding adequately to itraconazole therapy. Liposomal amphotericin B proved effective in refractory cases, highlighting the need for individualized treatment plans and improved access to therapeutic drug monitoring.
  • Published in:Current Medical Mycology,
  • Study Type:Case Report,
  • Source: PMID: 41122116, DOI: 10.22034/cmm.2025.345248.1613
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