[Dermatomycoses: topical and systemic antifungal treatment]. / Topische und systemische antimykotische Behandlung von Dermatomykosen.

Topical antifungals with activity against dermatophytes include amorolfine, allylamines, azoles, ciclopiroxolamine, and tolnaftate. Polyene antimycotics, such as amphotericin B and nystatin, alternatively, miconazole are suitable for yeast infections of the skin and mucous membranes. For severe yeast infections of the skin and mucous membranes, oral triazole antimycotics, such as fluconazole and itraconazole, are used. Pityriasis versicolor is treated topically with antimycotics, and in severe forms also orally with itraconazole, alternatively fluconazole. Terbinafine, itraconazole and fluconazole are currently available for the systemic treatment of severe dermatophytoses, tinea capitis and onychomycosis. In addition to proven therapeutic regimens, unapproved (off-label use) intermittent low-dose therapies are increasingly being used, particularly in onychomycosis. Oral antimycotics for the treatment of tinea capitis and onychomycosis in children and adolescents can only be used off-label in Germany. In general, any oral antifungal treatment should always be combined with topical antifungal therapy. In tinea corporis and tinea cruris caused by Trichophyton (T.) mentagrophytes ITS (internal transcribed spacer) genotype VIII (T. indotineae), there is usually terbinafine resistance. Identification of the species and genotype of the dermatophyte and resistance testing are required. The drug of choice for T. mentagrophytes ITS genotype VIII dermatophytoses is itraconazole. In individual cases, treatment-refractory onychomycosis may be due to terbinafine resistance of T. rubrum. Here too, resistance testing and alternative treatment with itraconazole should be considered. Therapy monitoring should be carried out culturally and, if possible, using molecular methods (polymerase chain reaction). Alternative treatment options include laser application, and photodynamic therapy (PDT).

[Conventional and molecular diagnostics in onychomycosis-part 1 : Conventional differentiation of dermatophytes-Trichophyton rubrum, Trichophyton interdigitale]. / Konventionelle und molekulare Diagnostik bei Onychomykose ­ Teil 1 : Konventionelle Differenzierung von Dermatophyten ­ Trichophyton rubrum, Trichophyton interdigitale.

Onychomycosis is a common infectious nail disease occurring worldwide. The mycological diagnosis of onychomycosis is primarily used for differential diagnostic differentiation from other, mostly inflammatory nail diseases, such as nail psoriasis or onychodystrophies of other causes. Conventional laboratory diagnostics when onychomycosis is suspected is based on microscopic detection of fungi in the nail material using fluorescence-optical potassium hydroxide preparations and culture of the pathogen. Molecular amplification methods allow a more sensitive and specific identification of the causative dermatophyte. Here, in 108 patients with onychomycosis, the dermatophytes were identified by culture and/or molecular biology using polymerase chain reaction (PCR) and the species identification was confirmed with subsequent sequencing. The dermatophytes were analyzed based on macromorphological and microscopic features. A dermatophyte was cultured in 56 of the 108 patients. Among them were 31 isolates of Trichophyton (T.) rubrum and 25 of T. interdigitale. All species identifications were subsequently confirmed by rDNA sequencing with concordant results in 54 of 56 patients. Two primarily as T. interdigitale identified specimens were revealed to be T. quinckeanum and T. tonsurans by molecular methods. T. quinckeanum, which is a zoophilic dermatophyte and a so-called emerging pathogen in dermatomycology, was isolated here for the first time as the causative agent of onychomycosis. The other dermatophyte, initially thought to be T. interdigitale, turned out to be T. tonsurans on molecular biology. This anthropophilic dermatophyte is also a rarity in onychomycosis. In addition, T. rubrum was identified by PCR in 34 of the 52 nail specimens that did not grow culture, and T. interdigitale in 18 nail specimens. However, the morphological identification of the four different dermatophytes species proved problematic. Neither the colony morphology nor the microscopic features of the dermatophytes allow clear differentiation of the pathogens. Microconidia, macroconidia, chlamydospores, and arthrospores are inconsistent in occurrence, number, microscopic distribution, and shape. The urease activity also did not allow an assignment of the dermatophyte species. These results indicate that the most sensitive detection and reliable identification of causative dermatophytes in onychomycosis is only possible by molecular methods.

[Conventional and molecular diagnostics in onychomycosis-part 2 : Molecular identification of causative dermatophytes by polymerase chain reaction and sequence analysis of the internal transcribed spacer region of ribosomal DNA]. / Konventionelle und molekulare Diagnostik bei Onychomykose ­ Teil 2 : Molekulare Identifizierung der ursächlichen Dermatophyten mit Polymerasekettenreaktion und Sequenzanalyse der ITS("internal transcribed spacer")-Region der ribosomalen Desoxyribonukleinsäure.

Dermatophyte identification using traditional methods such as optics-based direct fluorescence microscopy and culture is nowadays supplemented by molecular biological methods. The validity of dermatophyte DNA detection with direct uniplex-polymerase chain reaction-enzyme immunoassay (PCR-EIA) in nail samples was proven by sequence analysis of the ribosomal internal transcribed spacer (ITS) region. A total of 108 dermatophytes, isolated from patients with onychomycosis, were positive for Trichophyton rubrum (TR) and Trichophyton interdigitale (TI) in culture and/or uniplex-PCR-EIA. Conventional methods for dermatophyte identification were complemented by direct uniplex-PCR-EIA and sequence analysis of the ribosomal ITS region (18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA). Of 108 patients (average age 62, median age 73), 56 showed cultural growth with 31 of them being identified as TR and 23 as TI. There was high agreement with the sequence analysis. Surprisingly, the pathogen of a single nail sample was identified as T. quinckeanum (formerly T. mentagrophytes sensu stricto), a rare zoophilic dermatophyte in Germany. A single TI strain turned out to be a misidentified T. tonsurans based on the sequence analysis. In all, 34 of the 52 specimens lacking cultural growth were detected by PCR as TR, and 18 specimens could be identified as TI. The results of dermatophyte identification of culture-negative nail samples were also in agreement with the results of sequence analysis. Molecular biological methods are well applicable, and they show high reliability for direct dermatophyte identification in nail samples without prior cultivation. Especially for nail samples without cultural growth, PCR-based dermatophyte identification was highly specific and sensitive.

[Clinical picture, causative agents and diagnostics of dermatomycoses]. / Klinik, Erreger und Diagnostik von Dermatomykosen.

Dermatomycoses affect free skin, hairy scalp, fingernails and toenails. In addition, oral mucosa and genital mucosa can also be affected by fungal infections. The most common pathogens causing skin fungal infections are dermatophytes. They are responsible for, among others, tinea corporis, tinea capitis and onychomycosis (tinea unguium). Mainly anthropophilic dermatophytes are found as pathogens. In the case of tinea capitis-at least in Europe and in German-speaking countries-zoophilic skin fungi must also be considered. Rarely, geophilic dermatophytes can also be isolated. Yeast infections of the skin, mostly caused by Candida albicans, primarily affect the intertriginous skin areas, for example, the groin region, but also the submammary area and the spaces between the fingers and toes. Elderly patients are often affected, but also infants and, in particular, immunocompromised patients. These patient groups are also more frequently affected by oral mucosal infections caused by Candida albicans and other Candida species. Pseudomembranous candidiasis of the oral mucosa and tongue typically affects patients with HIV/AIDS. Mold infections in dermatology are relevant in onychomycosis of the big toenail. The causative agent is usually Scopulariopsis brevicaulis. Cutaneous mold infections are rare and only occur in immunocompromised patients. The mycological diagnosis of dermatomycoses is based on the microscopic, if possible fluorescence-optical detection of fungal hyphae and spores from skin scales, nail shavings and hair roots. The culture detection of dermatophytes, yeasts and molds allows the identification of the causative fungal species, but often fails, especially in patients who have already been treated with antifungal agents. In view of the high sensitivity and specificity of the molecular methods for fungal detection compared to culture, polymerase chain reaction (PCR) must realistically be regarded as the gold standard for dermatophytosis diagnostics. However, it should not be neglected that the three pillars of diagnostics-preparation, culture, PCR-currently deliver the best results.

[Microsporum ferrugineum-an anthropophilic dermatophyte in Germany : Case report and review of the literature]. / Microsporum ferrugineum ­ ein anthropophiler Dermatophyt in Deutschland : Patientenbeschreibung und Übersicht über die Literatur.

Three boys from the same city, treated by the same dermatologist, developed tinea capitis. Two of them, 4 and 8 years old, underwent mycological diagnostic workup. However, no pathogens familiar in this country, such as Microsporum (M.) canis or Trichophyton (T.) tonsurans, were isolated, but instead that of a dermatophyte that has not been found in Germany for decades. Both dermatophyte isolates showed white-beige-brownish colonies with a flat, radiating edge and a central, verrucous curvature. The sequencing of the internal transcribed spacer (ITS) region of the rDNA confirmed the suspicion of M. ferrugineum already expressed based on the morphological picture. The anthropophilic dermatophyte occurs in the Middle East, Asia, Eastern Europe and Africa and is considered to be the cause of tinea capitis or tinea corporis in children and adolescents. In 2016, M. ferrugineum has again been isolated in Germany, probably as a result of migration movements. The fungus is strikingly isolated to martial arts, especially wrestlers. It mainly affects children and adolescents, some with a Russian-German background. The anthropophilic dermatophyte is transmitted directly from person to person, especially in the case of tinea capitis. An indirect transmission, for example, via mats in martial arts is likely.