Management of asymptomatic coccidioidomycosis in patients with rheumatic diseases

Coccidioidomycosis is an endemic fungal infection common in the southwestern United States. Some rheumatology clinics periodically screen patients with coccidioidal serology, resulting in the identification of patients who are serologically positive but without clinical symptoms. The management of such patients is unclear. A retrospective study was conducted between 2007 and 2015 at two arthritis centers in Tucson, Arizona. The asymptomatic patients were identified who were receiving disease-modifying antirheumatic agents and had a positive coccidioidal serology. Serological testing including IgM and IgG was performed by enzyme immunoassay (EIA), immunodiffusion (IDTP and IDCF), or complement fixation. Out of 71 patients who were identified with positive coccidioidal serologies, 19 were asymptomatic. 18/19 patients continued antirheumatic therapy, 13 without interruption. 13/19 patients received no antifungal treatment, including 10 who remained on antirheumatic treatment. The other six were started on fluconazole, ranging from 8 to 73 months (median 30.5 months). After a median follow-up of 43 months, no patient developed clinically active coccidioidomycosis. Overall, 14 had only a positive EIA serological test. These results suggest that continued antirheumatic therapy is safe in asymptomatic patients with positive coccidioidal serological tests and that routine implementation of antifungal treatment may not always be warranted. The findings also raise concern regarding the utility of routine serological testing of asymptomatic patients residing in the coccidioidal endemic area, mainly using the EIA test.