Transmission of Onychomycosis and Dermatophytosis between Household Members: A Scoping Review

Abstract

Onychomycosis is a common fungal infection of the nail, caused by dermatophytes, non-dermatophytes, and yeasts. Predisposing factors include older age, trauma, diabetes, immunosuppression, and previous history of nail psoriasis or tinea pedis. Though many biological risk factors have been well characterized, the role of the environment has been less clear. Studies have found evidence of transmission in 44% to 47% of households with at least one affected individual, but the underlying mechanisms and risk factors for transmission of onychomycosis between household members are incompletely understood. A scoping literature review was performed to characterize and summarize environmental risk factors involved in the transmission of onychomycosis within households. A total of 90 papers met the inclusion criteria, and extracted data was analyzed in an iterative manner. Shared household surfaces may harbor dermatophytes and provide sources for infection. Shared household equipment, including footwear, bedding, and nail tools, may transmit dermatophytes. The persistence of dermatophytes on household cleaning supplies, linen, and pets may serve as lasting sources of infection. Based on these findings, we provide recommendations that aim to interrupt household transmission of onychomycosis. Further investigation of the specific mechanisms behind household spread is needed to break the cycle of transmission, reducing the physical and social impacts of onychomycosis.

Keywords: environment; family; household; onychomycosis; tinea; tinea unguium; transmission.

Figure 1

Summary of potential pathways involved in the household transmission of onychomycosis: (i) Shared surfaces within the household may harbor fungi and provide sources for transmission. Possible surfaces include patios, balconies, washrooms, showers, bathtubs, and areas of convergence such as entrances and hallways; (ii) Shared household equipment, including footwear, bedding, and nail tools, may facilitate transmission of onychomycosis; (iii) Fungi may also persist within the household environment, on cleaning tools, linen, and pets, serving as ongoing sources of infection.