Un nuevo enfoque sobre la epidemiología de las onicomicosis

Onychomycosis in patients with multiple sclerosis: prevalence, clinical description, mycological, and dermoscopic study in a Mexican population

BACKGROUND

Multiple sclerosis (MS) is a chronic demyelinating disease related to HLA-DR8. Susceptibility to onychomycosis has been found in Mexican mestizos with HLA-DR8. The frequency of onychomycosis in this neurological disease is unknown.

OBJECTIVES

To determine the frequency of onychomycosis and its clinical, mycological, and dermoscopic characteristics in patients with MS in comparison with the general population.

METHODS

Observational, cross-sectional, case-control study in patients with MS from October 2017 to February 2018. Age, gender, MS type, and time of progression from diagnosis to date and baseline treatment were collected after signed informed consent. A neurological exploration and clinical examination of fingernails and toenails for onychomycosis was conducted. Mycological and dermoscopic studies of the infected nails were performed on patients with clinical diagnosis of onychomycosis. A healthy control group was taken for each case (1:1), paired by age and gender.

RESULTS

The frequency of onychomycosis in patients with MS was higher than the healthy population (32% vs. 26%, P = 0.509). A higher frequency of non-dermatophyte fungi was found, although it was not statistically significant. The clinical manifestations and dermoscopic findings in patients with MS and onychomycosis were similar to those of the general population.

CONCLUSION

The frequency of onychomycosis in patients with MS is slightly higher than that of the general population. A possible association of HLA-DR8 as a susceptibility factor for onychomycosis is proposed. The etiology of opportunistic fungi in MS patients with onychomycosis may be related to immunosuppressive treatment.

Dermatophytes and other associated fungi in patients attending to some hospitals in Egypt

Dermatophytes are keratinophilic fungi that infect keratinized tissues causing diseases known as dermatophytoses. Dermatophytes are classified in three genera, Epidermophyton, Microsporum, and Trichophyton. This investigation was performed to study the prevalence of dermatomycosis among 640 patients being evaluated at the dermatology clinics at Kasr elainy, El-Husein and Said Galal hospitals in Cairo and Giza between January 2005 and December 2006. The patients were checked for various diseases. Tinea capitis was the most common clinical disease followed by tinea pedis and tinea corporis. Tinea cruris and tinea unguium were the least in occurrence. Tinea versicolor also was detected. The most susceptible persons were children below 10 years followed by those aged 31-40 years. Unicellular yeast was the most common etiological agent and T. tonsuranswas the second most frequent causative agent followed by M. canis.

Descriptive study of onychomycosis in a hospital in São Paulo

Onychomychosis, a nail fungus infection is the most frequent nail ailment, constituting about half of all nail disorders. It can be caused by dermatophytes, non-dermatophytes, yeasts and Prothoteca spp. Methods include 5407 samples of patients with suspected onychomycosis, studied from January 2002 to December 2006, by direct mycological examination and fungi culture. The diagnosis of onychomycosis was confirmed in samples from 3822 direct mycological and/or culture positive. The diagnosis was established by culture for fungi. Among the 1.428 identified agents, the dermatophytes were responsible for 68.6% (N = 980) of cases, followed by yeasts with 27.6% (N = 394), non-dermatophytes fungi with 2.2% (N = 31), Prothoteca spp with 0.1% (N = 2), and associations with 1.5% (N = 22). Females were more affected, with 66% (N = 2527) of cases, and the most affected age group ranged from 31 to 60 years of age (median 47 years). Fungal microbiota is often changed in the world, both quantitatively and qualitatively, and is affected by several environmental factors. Thus, the periodic review of the composition of this microbiota is important to evaluate the epidemiology and thus proportion a better therapeutic response.

Non-dermatophyte mould onychomycosis: a clinical and epidemiological study at a dermatology referral centre in Bogota, Colombia

Worldwide prevalence of non-dermatophyte mould onychomycosis has increased in recent years; however, available information on the topic is confusing and oftentimes contradictory, probably due to the small number of reported cases. The aim of this study was to determine and describe the aetiological agents, as well as the epidemiological and clinical characteristics of non-dermatophyte mould onychomycosis in a dermatology referral centre in Bogota, Colombia. A cross-sectional descriptive study was conducted between January 2001 and December 2011 among patients who attend the National Institute of Dermatology with a confirmed diagnosis of onychomycosis by non-dermatophytes moulds. There were 317 confirmed cases of non-dermatophyte mould onychomycosis in 196 women and 121 men whose average age was 43 years. Twenty-seven per cent of them had a history of systemic disease. The habit of walking and showering barefoot was the major infection-related factor. Distal and lateral subungual presentation was the most common pattern of clinical presentation. The most frequent non-dermatophyte mould was Neoscytalidium dimidiatum followed by Fusarium spp. No relationship was observed with predisposing factors previously reported in the literature. Clinical features found in this population are indistinguishable from onychomycosis caused by dermatophytes. High prevalence of N. dimidiatum found here was in contrast to a large number of studies where other types of moulds predominate.

[Onychomycosis: multicentre epidemiological, clinical and mycological study]

BACKGROUND

Onychomycosis accounts for up to 50% of all nail disorders. They can be caused by: yeasts, dermatophytes and non-dermatophyte moulds.

OBJECTIVES AND METHODS

A multicentre study designed to determine the prevalence, mycological test results, aetiological agents, and clinical presentation of onychomycosis was carried out. All fingernail and toenail samples taken during a one year period at 9 diagnostic centres were included.

RESULTS

A total of 5,961 samples were analysed, of which 82.3% were from toenails and 17.7% from fingernails. The mean age of the patients was 49.7 years, and 66% were females. Direct microscopic examination was positive in 61% of the samples. In adults, 61.2% of toenails were positive using potassium hydroxide (KOH), and 43.7% were positive in cultures. The prevailing aetiological agents belong to the dermatophyte group (82.8%), and distal subungual was the most common clinical form. In fingernails, direct examination showed 59.8% positive samples, and cultures were positive in 52.9%. The prevailing agents were yeasts belonging to Candida species, and onycholysis was the most common lesion.

CONCLUSIONS

Direct mycological examinations were positive in 61%, a higher value than that found in other series. Dermatophytes were prevalent in toenails of both sexes, and in finger nails yeast were prevalent in females, and dermatophytes in males. Non-dermatophyte moulds corresponded to 4.8% of toenail and 2.05% of fingernails isolates.

In vitro activity of voriconazole against dermatophytes, Scopulariopsis brevicaulis and other opportunistic fungi as agents of onychomycosis

Using a reference microdilution method, we studied the antifungal susceptibility to voriconazole and fluconazole of 304 clinical isolates from four species of onychomycosis-causing dermatophytes, 196 isolates of dermatophytes not related to nail infection as well as Scopulariopsis brevicaulis, Fusarium spp. and Scytalidium dimidiatum. Results showed a high antifungal activity of voriconazole against dermatophytes (geometric mean minimal inhibitory concentration (MIC)=1.14 microg/mL; MIC for 50% of the organisms (MIC(50))=0.062 miccrog/mL; MIC for 90% of the organisms (MIC(90))=0.25 microg/mL). For S. brevicaulis, the in vitro activity of voriconazole was considerably lower (geometric mean MIC=8.52 microg/mL; MIC(50) and MIC(90)=16 microg/mL). Although voriconazole is not among the drugs recommended for the management of onychomycosis, it can be a useful alternative for recalcitrant infections.

Medically important fungi found in hallux nails of university students from Cali, Colombia

The presence of medically important fungi was studied in hallux nails scrapings obtained from 504 students (204 males, 300 females) of three universities in Cali. Specimens were examined by direct microscopic examination and fungal culture. Medically important fungi were found in 49 (9.7%) students, 24 (4.8%) had onychomycosis while the rest did not have nail lesions. Trichophyton rubrum was the most commonly isolated fungi in students with lesions, where as T. mentagrophytes predominated in healthy nails. Most of the students with fungi were males. The prevalence of fungi was higher in individuals between 26 and 35 years. No association was observed between fungi and practicing sports or undergoing pedicures. These results suggest that dermatophytes can be found in healthy hallux nails, which can be reservoirs of pathogenic fungi.

Onychomycosis in older patients

Onychomycosis represents the most frequent nail disorder. Its prevalence is influenced by gender, age and several comorbid diseases. Accurate diagnosis relies on laboratory examination, particularly nail histomycology. This method refers to the microscopic examination of histological sections prepared from nail clippings for the purpose of detecting the presence of invading fungi. The pathogens may belong to one or a combination of the groups of dermatophytes, yeasts or nondermatophyte molds. The choice of the diagnostic laboratory method influences the accuracy of the information. Histomycology is recognized to be the most sensitive and specific method. The prevalence of onychomycosis in the elderly population varies according to gender and the nature of the fungal pathogen. Epidemiological figures differ according to the nature of the reference population. In particular, it is of the utmost importance to establish the ratio between the raw numbers of onychomycoses and the total number of individuals in the same age group living in the same geographical area.