Most doctors aren’t considering fungal infections when patients come in with pneumonia-even though, for some, that’s exactly what’s going on. A new study reveals that fungal testing for community-acquired pneumonia remains surprisingly low across the U.S., with only about 5% of outpatients getting tested for common, perhaps serious fungal infections.
Low Rates of Fungal Testing in Pneumonia Cases
A recent analysis of health insurance claims shows that testing for fungal pneumonia is infrequent, and diagnoses of endemic mycoses are relatively rare.
- Among nearly 574,000 adults with pneumonia, just 5% underwent fungal testing.
- The median time to testing was three healthcare visits after the initial pneumonia diagnosis.
- Of those tested, 3% ultimately received a diagnosis of blastomycosis, histoplasmosis, or coccidioidomycosis.
- specific symptoms-like rash for coccidioidomycosis and unexplained weight loss for histoplasmosis-can help identify patients who may benefit from testing.
Fungal pneumonias-caused by blastomycosis, histoplasmosis, and coccidioidomycosis-are often misdiagnosed as more common bacterial or viral pneumonias, as symptoms often mimic other, more common causes of pneumonia. A retrospective study analyzing commercial health insurance claims from 2017 to 2023 sought to understand how often these tests are actually ordered and how frequently they yield a diagnosis. Researchers used data from the Merative MarketScan Commercial and Medicare Database.
The analysis included 573,994 adults diagnosed with unspecified community-acquired pneumonia in outpatient settings. Of those, 25,822-roughly 5%-received testing for the three fungal infections. Interestingly,testing didn’t usually happen right away. the median time to testing was three healthcare visits after the initial pneumonia diagnosis.
Diagnoses After Fungal Testing
Of the patients who *were* tested, 755 (about 3%) ultimately received a diagnosis of blastomycosis, histoplasmosis, or coccidioidomycosis. The study also pinpointed clinical clues that raised the likelihood of a positive diagnosis.
A: For coccidioidomycosis, a rash was a key indicator. For histoplasmosis, autoimmune inflammatory disease and unexplained weight loss were strong signals. These findings suggest that paying attention to specific symptoms could help doctors order the right tests sooner.
For coccidioidomycosis, the presence of a rash significantly increased the odds of a diagnosis. Other associated factors included swollen lymph nodes, muscle aches, and chest pain.Patients who had received antibiotics from more than one drug class were also more likely to be diagnosed with coccidioidomycosis, potentially indicating that initial treatments weren’t effective.
When it came to histoplasmosis, autoimmune inflammatory disease and chest pain were associated with higher diagnosis rates. Though, abnormal weight loss showed the strongest correlation, suggesting that systemic symptoms might be particularly helpful in distinguishing histoplasmosis from other types of outpatient pneumonia.
The authors concluded that testing rates for these endemic mycoses remain low in many areas of the U.S. they propose that greater awareness and earlier consideration of fungal causes of pneumonia could lead to fewer repeat doctor visits and a reduction in unnecessary antibiotic prescriptions, ultimately improving patient outcomes.
Reference: Benedict K et al. Blastomycosis, Histoplasmosis, and Coccidioidomycosis in Outpatient Community-Acquired Pneumonia. JAMA Network Open. 2026;9(1):e2553965.
