An overview of topical antifungal therapy in dermatomycoses. A North American perspective

Dermatophytes cause fungal infections of keratinised tissues, e.g. skin, hair and nails. The organisms belong to 3 genera, Trichophyton, Epidermophyton and Microsporum. Dermatophytes may be grouped into 3 categories based on host preference and natural habitat. Anthropophilic species predominantly infect humans, geophilic species are soil based and may infect both humans and animals, zoophilic species generally infect non-human mammals. It is important to confirm mycologically the clinical diagnosis of onychomycosis and other tinea infections prior to commencing therapy. The identity of the fungal organism may provide guidance about the appropriateness of a given topical antifungal agent. Special techniques may be required to obtain the best yield of fungal organisms from a given site, especially the scalp and nails. It is also important to realise the limitations of certain diagnostic aids e.g., Wood's light examination is positive in tinea capitis due to M. canis and M. audouinii (ectothrix organisms); however, Wood's light examination is negative in T. tonsurans (endothrix organism). Similarly, it is important to be aware that cicloheximide in culture medium will inhibit growth of non-dermatophytes. Appropriate media are therefore required to evaluate the growth of some significant non-dermatophyte moulds. For tinea infections other than tinea capitis and tinea unguium, topical antifungals may be considered. For effective therapy of tinea capitis an oral antifungal is generally necessary. Similarly, oral antifungals are the therapy of choice, especially if onychomycosis is moderate to severe. Furthermore, where the tinea infection involves a large area, in an immunocompromised host or if infection is recurrent with poor response to topical agents, then oral antifungal therapy may be necessary. Topical antifungal agents may be broadly divided into specific and nonspecific agents. The former group includes the polyenes, azoles, allylamines, amorolfine, ciclopirox and butenafine. Generally the topical agent is available as a cream, sometimes for use intravaginally. Less commonly, the formulation may be in the form of a powder, lacquer, spray, gel or solution. Many of these agents have a broad spectrum of activity, being effective against dermatophytes, yeasts and Malassezia furfur. For the treatment of tinea corporis, tinea cruris tinea versicolor and cutaneous candidosis, once or twice daily application may be required, the most common duration of therapy being 2 to 4 weeks. For tinea pedis the most common treatment duration is 4 to 6 weeks.

[Effect of domestic laundry processes on mycotic contamination of textiles]

Inadequately decontaminated clothing may be a source of reinfection following therapy of dermato- and onychomycoses. The objective of this study was to determine whether domestic laundering is suitable for cleansing mycotically contaminated garments. Textile-samples contaminated with Trichophyton rubrum, Trichophyton mentagrophytes, Candida albicans and Scopulariopsis brevicaulis were washed in an ordinary washing machine at different temperatures. Regardless of the textiles and detergents used, reliable decontamination was achieved by laundering at 60 degrees C. Trichophyton rubrum was eliminated with a washing temperature of 30 degrees C.

Outbreak of invasive mycoses caused by Paecilomyces lilacinus from a contaminated skin lotion

BACKGROUND

Invasive mycoses are an important cause of illness and death in immunocompromised patients. Infections with molds other than aspergilli have been increasingly seen in patients with hematologic cancers, but epidemics of these infections have not yet been reported.

OBJECTIVE

To describe an outbreak of invasive mycoses with Paecilomyces lilacinus in severely neutropenic patients.

DESIGN

An outbreak investigation.

SETTING

The hematology-oncology isolation and bone marrow transplantation unit of the University Hospital, Basel, Switzerland.

PATIENTS

25 consecutive patients admitted between 17 August 1993 (the date of the first manifestation of P. lilacinus infection) and 31 October 1993 (when the unit was closed).

MEASUREMENTS

Clinical and microbiological data, including histologic findings; cultures from several patient sites; and environmental examinations of potential airborne, parenteral, enteric, and horizontal routes of transmission. Infections were defined by the isolation of P. lilacinus from clinically evident skin eruptions.

RESULTS

12 of the 25 patients (48%) were infected or colonized. Nine patients (36%), including all bone marrow transplant recipients, had documented invasive P. lilacinus infections. All 9 infected patients had papular, pustular, or necrotic skin eruptions. Two patients with severe graft-versus-host disease died with refractory fungal disease; 1 also had microbiologically documented endophthalmitis and kidney infiltrates. Seven affected patients no longer had P. lilacinus after recovery of bone marrow function. The organism was resistant in vitro to amphotericin B, itraconazole, and fluconazole. Patients did not respond clinically to these agents. The outbreak was ultimately traced to a contaminated, commercially available, pharmaceutically prepared skin lotion. The outbreak ended after the skin lotion was recalled and has not recurred after a follow-up period of 2 years.

CONCLUSION

Contaminated skin lotion is a potential cause of opportunistic fungal infections in immunocompromised hosts. Paecilomyces lilacinus is a common saprophytic mold that can cause, by direct cutaneous inoculation, invasive infections associated with illness and death.

Kitchens as a source of Aspergillus niger infection

In this study we investigated the epidemiology of a cluster of cutaneous infections owing to Aspergillus niger, which occurred in neutropenic patients in a bone marrow transplant unit. Heavy environmental contamination with the mould was found in the ward kitchen adjacent to the unit. The clinical and environmental isolates were typed by random amplification of polymorphic DNA (RAPD), which showed one of the patients was infected with the same strain as that isolated repeatedly from the kitchen area. In another case, contaminated stockinette material was implicated as the source of infection. Thorough cleaning of the ward kitchen resulted in no further cases on the unit. This highlights the fact that aspergilli may spread to patients by air, food or other vehicles, and underlines the importance of searching for a source and ensuring high levels of hospital hygiene are maintained.

Isolation of keratinophilic fungi from the floors of private veterinary clinics in Italy

To evaluate the presence of keratinophilic fungi in the environment, 400 samples were collected from the floors of 50 private veterinary clinics using 55-mm-diameter 'contact plates', containing mycobiotic agar. After incubation for 15 days at 25 degrees C, the following species were isolated: Microsporum canis, Trichophyton terrestre, Chrysosporium keratinophilum, Chrysosporium sp., Microsporum gypseum, Trichophyton ajelloi, Chrysosporium tropicum, Trichophyton mentagrophytes, Chrysosporium state of Arthroderma tuberculatum and Chrysosporium pannorum. It is concluded that the keratinic material shed by infected pets may contribute to the development and propagation of dermatophytes and related fungi in veterinary clinics. Therefore, such veterinary clinics may represent sites where pets and humans are exposed to risk of infection with keratinophilic fungi from the environment.

Dermatophytes from cases of skin disease in cats and dogs in Turin, Italy

In urban environments, pet animals such as dogs and cats may be largely responsible for the progressive increase of zoophilic over anthropophilic dermatophytes in the aetiology of human dermatophytoses. Mapping, in each city, of the natural foci of zoophilic dermatophytes may thus be important for understanding the epidemiology of human dermatophytoses, and for planning preventive measures. We have surveyed dogs and cats suspected of carrying dermatophytic lesions in the Turin area. Hairs, skin scrapings and the contents of pustules or vesicles were inoculated on Dermasel agar supplemented with choramphenicol and cycloheximide. The mating type of the isolates was checked, testing their compatibility with the two mating types of Arthroderma simii Stockdale, Mackenzie and Austwick. We isolated dermatophytes from about 40% of the cases examined. Microsporum canis Bodin was the only dermatophyte found in the lesions. In the cats the lesions were more frequent, in the dogs more severe. Animals less than a year old and male dogs were most often affected. Some cases of transmission of the infection between animals and from animals to man are described. All the isolates of M. canis, tested for mating behaviour, were non-reactive.

Isolation of dermatophytes and other keratinophilic fungi from surface sediments of the Shatt Al-Arab River and its creeks at Basrah, Iraq

Twenty-five sediment samples were taken from randomly selected sites in the Shatt Al-Arab River and its creeks and analysed for dermatophytes and related keratinophilic fungi. The results revealed that out of 25 samples only 13 (52%) yielded dermatophytes and related keratinophilic fungi. A total of nine species in four genera were isolated. The most frequent genera isolated in this study were Chrysosporium and its teleomorph Aphanoascus. The species most frequently found were Aphanoascus fulvescens, A. durus, Chrysosporium crassitunicatum, Chr. keratinophilum and Chr. tropicum (each n = 3). Microsporum was represented by two species, namely M. fulvum and M. gypseum. Trichophyton was represented by one species, T. verrucosum. The occurrence of these fungi illustrates that sediments may act as a reservoir for potentially pathogenic fungi for human and animals.

[Spread of a Microsporum canis infection in an agricultural facility (case description)]

In a combined pig production and fattening unit the weaned piglets on the flatdecks and some young fattening pigs were suffering from a Microsporum canis-infection. Besides the pigs the children of the farmer showed skin alterations. The infection was spread probably by the cats, which had access to the houses for sows and for sows with piglets. In cases of uncertain skin alterations, a mycologic etiology should be considered.

Ecology and epidemiology of dermatophyte infections

Our knowledge of ecology and epidemiology of dermatophytes and the factors influencing their transmission has helped us understand better the natural history of dermatophytoses. It seems that the anthropophilic agents of scalp infection are being eradicated in developing nations. The exception is Trichophyton tonsurans-related tinea capitis in North America. Microsporum canis is a prevalent agent of tinea capitis in many regions of the world, and this could be related to close association of humans with their pets. Trichophyton violaceum is endemic in certain parts of Eastern Europe, Africa, Asia, and South America but not in North America. Trichophyton rubrum is the most common cause worldwide of tinea pedis, nail infection, tinea cruris, and tinea corporis. Although the incidence of tinea capitis is declining in developed nations, tinea pedis and onychomycosis are becoming more common. The increased use of athletic shoes both by men and women and communal bathing could be contributing factors. Five or six species account for most dermatophytoses globally.

Microsporum canis infection in a 5-year-old boy: transmission from the interior of a second-hand car

Microsporum canis is one of the most common zoophilic dermatophytes. If transmitted to humans, inflammatory lesions may develop, e.g. on the scalp. M. canis was isolated from a 5-year-old boy living in a suburban area who suffered from a long-standing, mildly inflammatory lesion on the scalp that had been treated for several months with anti-eczematous regimens. There had been no contact with animals, e.g. cats or dogs, in the previous months, but the lesions had developed a few weeks after the family had bought a used car from a dog owner. Indeed, M. canis could be grown on contact plates from the car's interior. This case illustrates that attention should be paid to the often neglected diagnosis of M. canis-induced tinea capitis and to unusual routes of infection.

[Microsporum nanum. A fourth report of human infection in Brazil]

The authors present the fourth Brazilian case of human Microsporum nanum (M. nanum) infection. A child of nine months old presents cutaneous dorsal lesions compatible with tinea corporis, which appeared one month before. The culture revealed M. nanum. The lesions resolved spontaneously after a month. Epidemiologic investigation in the patient's place of origin identified swine infected by M. nanum, indicating the probable source of the infection.

Tinea corporis due to Microsporum canis from an asymptomatic dog

The patient was a 19-year-old female student who purchased a puppy from a pet shop four weeks earlier. At the time of her first examination, an annular edematous erythema with adherent scales and vesicles surrounding its margin was seen on the left forearm. On direct examination of the vesicles, fungal elements were detected, and Microsporum canis was isolated. The puppy was a Pomeranian and was kept in the house at all times. No clinical lesions were seen on the puppy, and the Wood's lamp test was negative. However, M. canis was isolated from the animal by the hairbrush method. Symptoms disappeared after the patient was treated topically with terbinafine cream for three weeks. Although the dog received no treatment whatsoever, there was no evidence of the disease on the pet. Results of the hairbrush method performed on the pet two and three weeks later were negative, but, at five weeks, it was again positive. Human infection with M. canis from an asymptomatic dog was demonstrated in this case. Attention should be paid to preventing infections from animals without lesions.

Fungal skin infections associated with animal contact

Zoophilic dermatophytes are fungal organisms that primarily infect animals but occasionally infect humans. The most common of these are Microsporum canis and Trichophyton mentagrophytes. The clinical lesions of zoophilic fungal infections are more inflammatory than those caused by the typical anthropophilic fungi normally transmitted from person to person. To diagnose zoophilic fungal infections, a potassium hydroxide preparation of the skin scrapings may be examined microscopically or a culture may be obtained. Small lesions located anywhere except on the scalp may be treated with a topical antifungal agent. Oral griseofulvin is preferred for the treatment of scalp infections and extensive cutaneous infections.

Infections transmitted by large and small laboratory animals

Although zoonotic spread of infectious disease continues to occur in laboratory animals used in biomedical research, reported outbreaks have been minimized with the advent of rigorous veterinary and husbandry procedures, the use of commercially reared animals, and the institution of appropriate personnel health programs. Maintaining animals in modern facilities with appropriate safeguards against introduction of vermin and biologic vectors is also important in preventing zoonotic disease in personnel. Nevertheless, established zoonotic agents, newly discovered microorganisms, or new animal species not previously recognized as carriers of zoonotic microorganisms are encountered, and the potential for spread of infectious disease from animals to humans still exists. Active dialogue between veterinarians and physicians regarding the potential of zoonotic disease, the species of animals that are involved, and the methods of diagnosis, is an indispensable component of a successful preventive health program involving personnel who deal with laboratory animals.

An epizootic of cutaneous zygomycosis in cultured dwarf African clawed frogs (Hymenochirus curtipes) due to Basidiobolus ranarum

Morbidity and mortality approaching 100% occurred in dwarf African clawed frogs (Hymenochirus curtipes) from a culture facility in central California. Moribund frogs exhibited preference for a terrestrial environment rather than their normal aquatic environment. Affected animals had a slight pallor of the integument but were otherwise grossly unremarkable. Microscopic examination revealed a fungal infection of the integument primarily characterized by the presence of surface and intra-epidermal conidia. Skin cultures of the infected animals yielded an organism identified as Basidiobolus ranarum, based on the formation of conidia in culture with internal cleavage to form sporangiospores. The organism was transmitted to healthy frogs by co-habitation with infected frogs but not by short-term immersion exposure of healthy frogs to homogenized broth cultures of the fungus. Benzalkonium chloride at 2.0 mg l-1 was efficacious in controlling the infection. Although Basidiobolus species are normally found in the intestinal tract of amphibians, the severity of this epizootic indicates that B. ranarum may be an important pathogen of amphibians reared in culture facilities.

[Urban cycles of zoonotic mycoses]

Based on their own results assembled during mycological examinations of 9958 subjects, 5496 animals and 648 specimens of non-animal substrates, and using data from the literature, the authors tried to formulate general laws concerning the prevalence of causal agents of mycoses with a zoonotic character which circulate steadily in urban areas: Microsporum canis, M. persicolor, Trichophyton mentagrophytes, M. equinum and T. equinum, T. verrucosum, some geophilic dermatophytes, Cryptococcus neoformans and Emmonsia crescens. In the characteristics of different urban cycles they used as a basis the evaluation of the prevalence of reservoir animals and reservoir substrates on the territory of towns and the evaluation of the most frequent routes of transmission of the agents from extrahuman sources to man. Preventive provisions leading to a reduction of the risk of the disease in humans must be specific with regard to different urban cycles.

[Dermatophytosis in a urban setting: prospective study of 135 cases]

During a period of one year all patients referred to the Dermatology department with the diagnosis of dermatophytosis were studied to determine the incidence. Etiology, and epidemiology of these infections in the northeast of Madrid. We have evaluated the sensitivity and specificity of the direct examination with 10% KOH with respect to the culture as well as the correlation between the clinical diagnosis and the result of the mycologic examination. The annual incidence was 8.4 cases per 10,000 inhabitants and the most frequent causal agents in a total number of 135 patients were Epidermophyton floccosum in 48 (35.5%), Microsporum canis in 36 (26.6%), Trichophyton mentagrophytes in 28 (20.7%) and Trichophyton rubrum in 12 (8.8%). In 5 patients there were simultaneous infection by two different agents. In a third part of the cases a previous contact with animals was reported. The direct examination had a specificity of 98% and a sensitivity of 83%. The diagnosis in the nonungual infections was confirmed in the 54% of the cases. The incidence of dermatophytosis in our geographical area is high. Due to the similarities with other diseases, the mycologic examination by microscopy or culture is essential.

[Transmission of "barber's itch" by bathing?]

Pathogenic fungi find a favourable environment in baths for multiplication and distribution. So diseases caused by dermatophytes are often observed in connection with a visit of a bath. With regard to transmission of a "barber's itch" caused by fungi in consequence of the visit of a bath, there have still no results been published. Considering previous knowledge about epidemiology, mechanism of invasion, living, and multiplication of pathogenic fungi it seems unlikely that a transmission of the germs of "barber's itch" takes place due to the visit of a public bath. The expression "barber's itch" is not uniformly used; thus, if visitors make complaints about this affection, an etiological differentiation is required.

A familial occurrence of sporotrichosis

A grandfather and granddaughter suffering from sporotrichosis were reported. It is thought that they might have been infected from the same source of Sporothrix schenckii (S. schenckii).

[Dermatomycoses as occupational diseases. The causative agents, sources of infection and the involved occupations]

Fungal diseases of the skin can be occupational dermatoses. This applies in particular to diseases due to microorganisms acquired from animals. A discussion of the relationship between occupation and disease, however, is not only pertinent in regards to dermatophytoses due to zoophilic fungi but also with those due to geophilic and--to a certain extent--even anthropophilic ones. The same is true of candidiasis. The present review deals with the various standpoints concerning the role of occupation in the development of cutaneous mycoses. In addition casuistic evidence for the various types disease, is compiled and discussed.