Guidance updated on histoplasmosis

The Infectious Diseases Society of America (IDSA) has issued two updates to its clinical practice guideline on the management of histoplasmosis.

The first update was published July 8 by Clinical Infectious Diseases and covers treatment of asymptomatic Histoplasma pulmonary nodules, or histoplasmomas, which are defined by evidence of recent-onset or active infection.

The IDSA panel suggests against routinely providing treatment for histoplasmosis to prevent reactivation in adults and children with asymptomatic noncalcified pulmonary nodules related to histoplasmosis with no evidence of other active sites, or in asymptomatic patients with known untreated prior infection (conditional recommendation, very low certainty of evidence). Patients who are at higher risk for disseminated or severe histoplasmosis, especially those with immunocompromising conditions, should be closely monitored for clinical or radiological change, or treatment should be considered, the update said. Patients with only calcified pulmonary nodules should not be treated.

The second update was published July 10 by Clinical Infectious Diseases and covers treatment of mild and moderate acute pulmonary histoplasmosis. Mild disease is defined by symptoms that don't interfere with normal activities, while moderate disease is defined by symptoms that may interfere significantly and require low-flow oxygen supplementation and/or hospitalization, the update said.

The IDSA panel suggests against routine antifungal treatment in immunocompetent adults and children with mild acute pulmonary histoplasmosis (conditional recommendation, very low certainty of evidence). Treatment may be considered in immunocompetent patients with mild acute pulmonary histoplasmosis who have prolonged illness, progression of pulmonary infiltrates, or enlarging hilar or mediastinal adenopathy, the panel noted.

For immunocompetent adults and children with moderate acute pulmonary histoplasmosis, the IDSA panel suggests either antifungal treatment or no antifungal treatment, considering the severity and duration of signs/symptoms, as well as potential harms of antifungal treatment (conditional recommendation, very low certainty of evidence). The panel noted that this is a heterogeneous group of patients and that longer illness, progression of pulmonary infiltrates, enlarging hilar or mediastinal adenopathy, and more severe signs or symptoms favor treatment. Drug-drug interactions, other benefits and harms, and financial burden should also be considered in treatment decisions, the panel said.

The IDSA panel suggests antifungal treatment in immunocompromised adults and children with mild or moderate acute pulmonary histoplasmosis who are at moderate to high risk of progression to disseminated disease (conditional recommendation, very low certainty of evidence). Treatment may not be warranted in those whose disease is asymptomatic or mild and who have less severe immunocompromise, the panel said.

Itraconazole is preferred when treatment is indicated, and those who receive it should also receive therapeutic drug monitoring, according to the statement.

In all cases, for both histoplasmomas and mild and moderate acute pulmonary histoplasmosis, treatment of pregnant patients should only be considered after careful weighing of potential benefits and harms of treatment, ideally with specialists in maternal-fetal medicine and infectious diseases. If treatment is necessary, azoles should be avoided in the first trimester when possible and liposomal amphotericin B should be used instead, according to both updates.