Tinea manuum: A report of 18 cases observed in the metropolitan area of Milan and review of the literature

Expert Panel Review of Skin and Hair Dermatophytoses in an Era of Antifungal Resistance

Dermatophytoses are fungal infections of the skin, hair, and nails that affect approximately 25% of the global population. Occlusive clothing, living in a hot humid environment, poor hygiene, proximity to animals, and crowded living conditions are important risk factors. Dermatophyte infections are named for the anatomic area they infect, and include tinea corporis, cruris, capitis, barbae, faciei, pedis, and manuum. Tinea incognito describes steroid-modified tinea. In some patients, especially those who are immunosuppressed or who have a history of corticosteroid use, dermatophyte infections may spread to involve extensive skin areas, and, in rare cases, may extend to the dermis and hair follicle. Over the past decade, dermatophytoses cases not responding to standard of care therapy have been increasingly reported. These cases are especially prevalent in the Indian subcontinent, and Trichophyton indotineae has been identified as the causative species, generating concern regarding resistance to available antifungal therapies. Antifungal-resistant dermatophyte infections have been recently recognized in the United States. Antifungal resistance is now a global health concern. When feasible, mycological confirmation before starting treatment is considered best practice. To curb antifungal-resistant infections, it is necessary for physicians to maintain a high index of suspicion for resistant dermatophyte infections coupled with antifungal stewardship efforts. Furthermore, by forging partnerships with federal agencies, state and local public health agencies, professional societies, and academic institutions, dermatologists can lead efforts to prevent the spread of antifungal-resistant dermatophytes.

Current Topics in Dermatophyte Classification and Clinical Diagnosis

Dermatophytes are highly infectious fungi that cause superficial infections in keratinized tissues in humans and animals. This group of fungi is defined by their ability to digest keratin and encompasses a wide range of species. Classification of many of these species has recently changed due to genetic analysis, potentially affecting clinical diagnosis and disease management. In this review, we discuss dermatophyte classification including name changes for medically important species, current and potential diagnostic techniques for detecting dermatophytes, and an in-depth review of Microsporum canis, a prevalent zoonotic dermatophyte. Fungal culture is still considered the “gold standard” for diagnosing dermatophytosis; however, modern molecular assays have overcome the main disadvantages of culture, allowing for tandem use with cultures. Further investigation into novel molecular assays for dermatophytosis is critical, especially for high-density populations where rapid diagnosis is essential for outbreak prevention. A frequently encountered dermatophyte in clinical settings is M. canis, which causes dermatophytosis in humans and cats. M. canis is adapting to its primary host (cats) as one of its mating types (MAT1-2) appears to be going extinct, leading to a loss of sexual reproduction. Investigating M. canis strains around the world can help elucidate the evolutionary trajectory of this fungi.

An uncommon cause of tinea: Trichophyton violaceum in a German kindergarten - outbreak report and quantitative analysis of epidemiological data from Europe

Background: Global mobility is increasingly associated with the emergence of "unusual" infectious agents. At the beginning of 2019, a putative outbreak of Impetigo contagiosa occurred in a kindergarten in Regensburg, Germany, that was mainly attended by children with a migrant background. After thorough examination, the outbreak was classified as infection with Trichophyton (T.) violaceum. Methods: Based on case investigations, infection control measures, disinfection, and cleaning were implemented. Microscopy of native specimens, fungal cultures, and polymerase chain reaction were used for diagnosis. Additionally, a systematic literature search in Medline, followed by a quantitative analysis of epidemiological data from Europe, were performed. Results: Between January and November 2019, 12 cases of tinea were diagnosed in 7 educators and 2 household members. Children were initially not affected. T. violaceum was only detected in 2 patients. No extensive screening measures were carried out after risk-benefit assessment. Studies on T. violaceum in Europe are heterogeneous, and the number of cases and the prevalence vary considerably. The pathogen is mainly found in children of African descent who clinically present with tinea capitis. Discussion: In the present case, the source of infection and the chain of transmission remained unclear. The pathogen could only be diagnosed in 2 cases. In Europe, the (re)emergence of pathogens such as T. violaceum is likely to be caused by increasing migration and travel. Pathogens should be identified for epidemiological reasons in all cases. In outbreaks, measures must be adapted to the dynamics of the individual outbreak after assessment of the risks, benefits, and proportionality.