Healthcare Provider Testing Practices for Tinea and Familiarity with Antifungal-Drug-Resistant Tinea—United States, 2022

Tinea, a dermatophyte fungal infection, is a common outpatient complaint that is easily misdiagnosed by visual inspection. Antifungal-drug-resistant tinea is an emerging global public health problem, with several cases reported in the United States. We analyzed data from a Spring 2022 web-based survey of healthcare provider attitudes and practices. Among 1500 healthcare providers, only 20.1% reported typically using diagnostic testing for tinea, and 19.5% reported clinical experience with drug-resistant tinea. Drug-resistant tinea may be more widespread than previously recognized. However, the low frequency of diagnostic testing indicates potential misunderstanding or misdiagnosis of drug-resistant tinea and missed opportunities to detect drug-resistant cases.


Introduction
Tinea, also called ringworm or dermatophytosis, is a common infection of the skin, hair, or nails caused by dermatophyte fungi [1,2]. The infection can spread by fomites, between people, and between people and animals. The classic tinea lesion is an erythematous, raised, scaly annular rash with central clearing. The sites typically affected include feet (tinea pedis), hands (tinea manuum), groin (tinea crutis), scalp (tinea capitis), and other body sites (tinea corporis). Tinea can be easily misdiagnosed by visual inspection alone [3,4], potentially leading to inappropriate treatment, worsening of symptoms, or secondary bacterial infections. Available methods to confirm a diagnosis of tinea include direct microscopy, fungal culture, and fungal polymerase chain reaction. Routine diagnostic testing is generally only recommended for suspected tinea of the scalp and nails [1]. Healthcare provider (HCP) testing practices for tinea have not been well-described but may be increasingly important to understand given the global emergence of antifungaldrug-resistant tinea, a public health threat [5]. Although the extent of this problem in the United States is unclear, several US cases of antifungal-drug-resistant tinea have been reported [6,7]. To help inform tinea diagnosis and prevention efforts, we assessed HCP self-reported testing practices for tinea and familiarity with drug-resistant tinea.

Materials and Methods
We analyzed data from the Spring 2022 DocStyles survey, a web-based survey of HCP attitudes and practices commissioned by Porter Novelli Public Services and conducted by SERMO during 16 March to 4 May 2022. We analyzed two questions: "What methods do you typically use to diagnose patients with tinea (ringworm) on initial presentation?" and "Before this survey, were you familiar with reports of drug-resistant tinea (ringworm)?" Respondents included family practitioners, internists, pediatricians, nurse practitioners, and physician assistants; all respondents were actively seeing patients in the United States and had been practicing for ≥3 years. We evaluated HCP features associated with (a) typically ordering diagnostic testing for tinea and (b) having seen, diagnosed, or consulted on cases of drug-resistant tinea using chi-square tests. We used t-tests to assess bivariate relationships and multivariable logistic regression with backward selection to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI).

Results
Among the 2591 HCPs invited to participate in the survey, 1753 (67.7%) completed it, and 1500 were asked the tinea questions. The HCPs were mainly internists (34.3%) or family practitioners (32.4%) in a group outpatient practice or clinic (64.9%) ( Table 1). Most HCPs (71.0%) said they diagnose tinea based on physical exam alone, whereas 20.1% typically use laboratory testing for tinea, most frequently with an in-office stain with microscopy (11.0%) ( Table 2).

Discussion
In this survey of HCPs, one in five providers reported clinical experience with drugresistant tinea, suggesting that this emerging issue may be more widespread in the United States than is represented by limited case reports [6,7]. However, a low proportion of HCPs reported typically performing diagnostic testing for tinea, indicating the potential for misdiagnosis and missed opportunities to detect antifungal drug-resistant cases. Together, the high reported familiarity with drug-resistant tinea and low testing could also indicate a possible misclassification of treatment failure as "drug-resistant tinea." The variability we observed in testing practices and experience with drug-resistant tinea may reflect differences in training and patient populations served. Factors influencing testing practices for tinea are also likely patient-related (i.e., demographic characteristics; site, severity, or clinical appearance of infection), which we did not evaluate. HCPs who see pediatric patients may be testing for tinea more often because tinea capitis is more common among children [8]. Possible reasons for the low testing rates include time constraints, lack of access to or unfamiliarity with in-house microscopy, or low insurance reimbursement rates. Social desirability bias may mean that testing for tinea is performed even less frequently than reported here. Conversely, HCPs may have overreported their familiarity with drug resistant tinea. A possible explanation for the relatively high reported rates of experience with drug-resistant tinea could be that providers were reporting tinea cases that failed treatment for reasons besides intrinsic antifungal resistance, such as incorrect diagnosis, improper treatment, or inadequate patient adherence to treatment [1]. In addition to potential misclassification of drug resistance, other limitations of this study include the lack of information about antifungal susceptibility testing and antifungal treatment practices.
Future work is needed to characterize the epidemiology of treatment-resistant tinea in the United States, using a One Health approach. The burden of treatment-resistant tinea is likely underestimated, particularly given providers' reliance on visual inspection for tinea diagnosis and low rates of testing.