Dermatophytosis caused by Nannizzia gypsea: report of 155 cases from Western Mexico.

Background: Dermatophytosis caused by Nannizzia gypsea are considered rare. The clinical picture is indistinguishable from that produced by other dermatophytes, but, being this a geophilic fungus, it can cause more inflammatory disease.

Methods: Retrospective study. Patients with positive culture for N. gypsea observed at the Dermatological Institute of Jalisco "Dr. José Barba Rubio", from 2001 to 2023, were included. Frequency, sex, age, evolution, and clinical variant were investigated. We compared the findings between the pediatric versus adult population. Descriptive and inferential statistics were used.

Results: Over 23 years, 155 patients were diagnosed (6.7 cases per year). Female sex predominated (53.5%). The median age was 9 years (minimum 1year and maximum 85 years), the more affected age group was 1-10 years (54.2%). The median time of evolution was 30 days (minimum one day and maximum three years), and 74.8% had an evolution ≤30 days. Tinea capitis predominated in pediatric patients (41.0%, p<0.01) whereas tinea corporis predominated in adults (72.7%, p<0.01). Inflammatory tinea was more prevalent in the pediatric population (21.0% vs. 3.6%, p<0.01).

Conclusion: The ability of Nannizzia gypsea to cause inflammatory tinea was observed primarily in pediatric patients. Since there is no clinical data to suspect this fungus, it will always be necessary to carry out a mycological study to identify the species and to implement the appropriate treatment.