Zoophilic dermatophytosis: A study of closed contact cases

Abstract

Dermatophyte infection is common in both humans and animals. Zoophilic species caused more inflammatory lesions than anthropophilic species. Treatment done only in humans caused reinfection and spreading of disease to other family members. The objective of this study is to find clinical correlation between dermatophyte infection in human and history of animal contact. This study was retrospectively done by reviewing medical records and telephone interview. Twenty five patients (4 males, 21females) were enrolled. All patients gave history of closed contact with animals. Average duration of animal contact was 24.6 (±31.8) days. The most common sites were arms and hands. Single lesion was found in 11 patients (44%). The detected organisms were Microsporum canis (M.canis) (48%)  and  Trichophyton mentagrophytes var. mentagrophytes (T.mentagrophytes) (52%). Eleven patients who were infected with M.canis, 10 patients contacted with cat and 1 patient with dog. T.mentagrophytes was cultured from 9 patients with rabbit contact, 2 patients with cats and 2 patients with dogs. In M.canis infection, the characteristic “vivid scaly erythematous ring(s)” was found.  These lesions erupted in a short period (less than 14 days). Up to 60% of M.canis infection presented with this characteristic skin lesion in our study. Therefore, this was a useful clinical sign. Eight patients (32%) had other family members infected with dermatophytes and 2 patients (8%) experienced reinfection. Nine animals were taken for investigation. Cultures from  9 patients and their pets revealed same pathogen. Interestingly, 85.7% of infected children under 15-year-old had history of rabbit contact. Nineteen patients (76%) were infected from normal looking animals. Use of Wood’s lamp examination in normal looking animals helps diagnosis of M.canis.