Microsporum nanum cutaneous infection in a traveller returning from Thailand: A diagnostic challenge

Ringworm by Nannizzia nana: Clinical case and literature review

INTRODUCTION

Human dermatophytoses are the most widespread infections caused by fungi. These are capable of invading the keratin-containing tissues of animals. Nannizzia nana (N. nana) can cause ringworm in pigs and rarely cause infections in humans.

METHODS

We conducted a search using PUBMED for articles published from January 1, 1990 to March 31, 2022 to identify additional cases. The search terms used were "Microsporum nanum" and "Nannizzia nana".

RESULTS

After reviewing the literature, we identified a total of 16 cases of dermatophytosis due to N. nana since 1990. In most of the patients, the clinical diagnosis was tinea corporis and the most widely used antifungals were: terbinafine and griseofulvin.

CONCLUSION

N. nana is a dermatophyte species isolated infrequently in humans, but it represents a potential source of dermatophytosis in people who come into direct or indirect contact with animals and soil.

Human and Zoonotic Dermatophytoses: Epidemiological Aspects

Introduction

Dermatophytes are a group of molds characterized by the ability to produce keratinases, thereby carving out for themselves specific ecological niches. Their traditional division into three genera, Trichophyton, Microsporum, and Epidermophyton has been expanded to nine and the species in each genus were modified. Dermatophytes are among the most prevalent causes of human and animal mycoses. Their epidemiology is influenced by various factors. These factors may be evolutive such as the predilected environment of the fungus, namely, humans (anthropophilic), animals (zoophilic), or environment (geophilic), is evolutionary and thus may require centuries to develop. Many other factors, however, result from a variety of causes, affecting the epidemiology of dermatophytoses within a shorter time frame.

Objective

This review aims at summarizing the factors that have modified the epidemiology of dermatophytoses during the last decades.

Results

Geographic and climatic conditions, demography such as age and gender, migration, socio-economic conditions, lifestyle, and the environment have had an impact on changes in the epidemiology of dermatophytoses, as have changes in the pattern of human interaction with animals, including pets, farm, and wild animals. A typical example of such changes is the increased prevalence of Trichophyton tonsurans, which spread from Latin America to the United States and subsequently becoming a frequent etiological agent of tinea capitis in Africa, Middle East, and other areas.

Conclusion

The comprehension of the epidemiology of dermatophytoses has a major bearing on their prevention and treatment. Since it is undergoing continuous changes, periodic assessments of the most recent developments of this topic are required. This article aims at providing such an overview.