Putting onychomycosis under the microscope

Onychomycosis in underrepresented groups: an all of us database analysis

Few research studies evaluating the impact of dermatologic diseases in the United States (US) have adequately included underrepresented groups. All of Us (AoU) is an ongoing precision medicine-based research initiative by the National Institutes of Health (NIH) that facilitates research in populations traditionally underrepresented in biomedical research by prioritizing them for data collection. Our objective was to evaluate the burden of onychomycosis in underrepresented groups defined by the framework provided by AoU. The AoU Registered Tier dataset version 5 was used which includes data collected between May 30, 2017 and April 1, 2021. We conducted a cross-sectional analysis linking survey and electronic health record (EHR) data to estimate the prevalence of onychomycosis in underrepresented groups defined by race, ethnicity, age (≥ 75 years), disability, sexual orientation/gender identity (LGBTQIA +), income (annual household income ≤ $35 000) and education (less than a high school degree). The latest All of Us data release includes 329,038 participants. Of these, 251,597 (76%) had EHR data and 13,874 had onychomycosis (overall prevalence, 5.5%; 95% CI, 5.4-5.6). Multivariate analyses adjusted by tinea pedis, diabetes mellitus, immune compromise, nail psoriasis, and insurance status, in addition to the aforementioned variables, revealed that, compared with White participants, Black and Hispanic participants had a higher adjusted odds of onychomycosis (OR, 1.29; 95% CI, 1.23-1.36 and OR, 1.24; 95% CI, 1.17-1.31, respectively). Higher adjusted odds of onychomycosis were also observed in underrepresented groups. Our findings suggest a disproportionately high burden of onychomycosis in underrepresented groups, although further studies are needed to replicate our findings and address this disparity.

Enhanced Ungual Permeation of Terbinafine HCl Delivered Through Liposome-Loaded Nail Lacquer Formulation Optimized by QbD Approach

The present investigation focused on developing, optimizing, and evaluating a novel liposome-loaded nail lacquer formulation for increasing the transungual permeation flux of terbinafine HCl for efficient treatment of onychomycosis. A three-factor, three-level, Box-Behnken design was employed for optimizing process and formulation parameters of liposomal formulation. Liposomes were formulated by thin film hydration technique followed by sonication. Drug to lipid ratio, sonication amplitude, and sonication time were screened as independent variables while particle size, PDI, entrapment efficiency, and zeta potential were selected as quality attributes for liposomal formulation. Multiple regression analysis was employed to construct a second-order quadratic polynomial equation and contour plots. Design space (overlay plot) was generated to optimize a liposomal system, with software-suggested levels of independent variables that could be transformed to desired responses. The optimized liposome formulation was characterized and dispersed in nail lacquer which was further evaluated for different parameters. Results depicted that the optimized terbinafine HCl-loaded liposome formulation exhibited particle size of 182 nm, PDI of 0.175, zeta potential of -26.8 mV, and entrapment efficiency of 80%. Transungual permeability flux of terbinafine HCl through liposome-dispersed nail lacquer formulation was observed to be significantly higher in comparison to nail lacquer with a permeation enhancer. The developed formulation was also observed to be as efficient as pure drug dispersion in its antifungal activity. Thus, it was concluded that the developed formulation can serve as an efficient tool for enhancing the permeability of terbinafine HCl across human nail plate thereby improving its therapeutic efficiency.

Environmental and Genetic Factors on the Development of Onychomycosis

Since the early 20th century, onychomycosis originated with the onset of war, the use of occlusive footwear, and the mass migration of people by transportation in the United States. Even though onychomycosis has a high prevalence in the US, other parts of the world including Canada, West Africa, Southeast Asia, Northern Australia, and Europe have been well documented with cases of fungal toenail infection in their environments. Trichophyton rubrum (T. rubrum) is the major dermatophyte responsible for toenail fungal infection and is typically diagnosed in conjunction with tinea pedis, especially in individuals older than 60 years. Gender roles, age, cultural habits, shoe gear, sports activities, and genetic predisposition all contribute to the different presentation of onychomycosis in these areas where organisms like dermatophytes, candida, and molds were isolated in a variety of cases. Despite the differences in isolated pathogens, treatment outcomes remained consistent. This literature review discusses the influence of tinea pedis, genetics, shoe gear, sports, and age on the development of onychomycosis.