Invasive dermatophyte infection: A systematic review

Dermatophyte infections usually present as various types of superficial cutaneous mycoses; on very rare occasions, dermatophytes enter deep into the dermis and cause invasive infections. In this study, we aimed to perform a systematic review of all reported invasive dermatophytosis cases over the past 20 years. We performed systematic searches in PubMed/Medline, EMBASE and Web of Science and identified 123 papers reporting 160 individual cases of invasive dermatophytosis between 2000 and 2020. Our study included 103 (64.4%) males, and the mean age at diagnosis was 43.0 years (range: 3-87 years). The most common predisposing factor was superficial dermatophytosis (56.9%), followed by solid organ transplantation (26.9%), the use of topical immunosuppressants (15.6%), gene mutations (14.4%), diabetes (14.4%) and trauma (6.9%). Trichophyton (T.) rubrum was the most prevalent pathogen (53.1%) responsible for invasive dermatophytosis, followed by T. mentagrophytes (7.5%), Microsporum canis (6.9%), T. tonsurans (5.6%), T. interdigitale (5.0%) and T. violaceum (3.8%). Patients with CARD9 or STAT3 mutations were prone to have mixed infection of two or more dermatophytes, present with eosinophilia and high IgE, and develop disseminated infections. Overall mortality was 7.9%, and the mortality in patients with and without gene mutations was 17.4% and 5.5%, respectively. Most of the normal host patients responded well to oral antifungal agents, while gene-deficient patients usually required lifelong treatment to stabilise their infection status. Our review indicated the importance of preventive treatment of superficial tinea in patients with immunosuppression and gene deficiencies to avoid the development of invasive dermatophytosis.