S1‐Leitlinie Tinea capitis

[Terbinafine-resistant dermatophytoses and onychomycosis due to Trichophyton rubrum]

BACKGROUND

In recent years, therapy-refractory courses of dermatophytoses have increasingly become the focus of attention. The most frequent pathogens are Trichophyton (T.) rubrum and T. mentagrophytes. In addition to local therapy, first-line treatment includes terbinafine, an allylamine antifungal agent that acts by inhibiting squalene epoxidase and thus interfering with ergosterol synthesis. In refractory cases, terbinafine resistance due to point mutation in the squalene epoxidase gene has been frequently detected.

OBJECTIVES

The aim is to present specific aspects in the epidemiology of dermatophytoses with terbinafine resistance and to illustrate them on the basis of four patient cases including diagnostic procedures.

MATERIALS AND METHODS

A review of handbook knowledge, a selective literature search, and a review of four patient cases were performed.

RESULTS

Detection of the terbinafine resistance was performed by in vitro testing using the breakpoint method as well as sequencing of the Trichophyton isolate and detection of the point mutation with amino acid substitution at position L393F or F397L of squalene epoxidase.

CONCLUSION

In refractory and recurrent dermatophytoses, terbinafine resistance should be considered, especially in T. mentagrophytes and T. rubrum, and in vitro resistance testing of the dermatophyte and point mutation analysis of squalene epoxidase (SQLE) should be performed. Therapeutically, intermittent administration of itraconazole in combination with antifungal local therapy is recommended. Nevertheless, a recurrent course is to be expected and long-term therapy with itraconazole is usually necessary.

[Renaissance of mouse favus : Retrospective analysis of Trichophyton quinckeanum infections at Jena University Hospital in the period 2015-2020]

The number of Trichophyton quinckeanum infections has increased significantly in recent years. In 2020 in particular, the number of cases increased fivefold compared to 2015. Infections multiplied, especially in the second half of the year, which correlated with the upsurge in field mouse populations. Typical vectors are mice and rats as well as dogs and cats, which hunt the rodents. The animals are usually asymptomatic. In humans, on the other hand, the course is usually more inflammatory corresponding to other zoophilic mycoses. Typical clinical manifestations of the infections are tinea corporis and tinea capitis. Treatment of T. quinckeanum infections is similar to other dermatophyte infections, depending on the severity, location and age of the patient as well as the immune status, previous illnesses and medication. The duration of local therapy should be at least 4 weeks and continued for up to 14 days after the normalization of the skin presentation. Systemic treatment should take place with terbinafine 250 mg once a day orally (in adults). Alternatives are itraconazole, fluconazole and griseofulvin. Only the preparation griseofulvin, which is no longer available in Germany, is approved for children. Alternatively, terbinafine, itraconazole or fluconazole can also be used in children as an "off-label" treatment in an individual healing attempt.

[Kerion Celsi due to Microsporum canis infection]

Tinea capitis is seen world-wide among children up to 12 years. The most severe type is Kerion Celsi with painful abscesses and lymphadenopathy. We report on an 11-year-old boy with Kerion Celsi, who was initially treated using antibiotics under the common misdiagnosis of a bacterial infection. Mycological investigations could identify Microsporum canis. The patient was treated orally with griseofulvin, which resulted in complete mycological remission after 8 weeks. Cicatrical alopecia, however, could not be prevented. Purulent infections of the scalp should lead to early mycological diagnostics in children.

[Trichophyton tonsurans-an emerging pathogen in wrestling in Germany]

Trichophyton (T.) tonsurans is considered as the main causative agent of tinea gladiatorum (ringworm) in contact and martial arts worldwide and regularly leads to outbreaks. In the national wrestling squad in Leipzig, dermatophytoses occurred frequently and recurrently in children and adolescents for over a 2-year period. The wrestlers came to the dermatologist's office for clinical examination and sampling. Dermal scales and hair roots as well as smears were examined mycologically with fluorescence optical preparation, fungal culture, and polymerase chain reaction (PCR) for dermatophyte DNA. Sequencing of the dermatophyte rDNA served as culture confirmation test. Environmental investigations in the wrestler training center included contact cultures and smears from surfaces, in particular from the mats. T. tonsurans was culturally and/or with PCR detectable in 21 out of 25 children and adolescents plus one trainer. T. tonsurans grew in one of ten contact cultures of mats and floors in the wrestling training center, and T. interdigitale was found in another culture. Smears from the mats resulted in a culture of T. tonsurans detection twice. The PCR was positive for T. tonsurans three times. Within 14 days, T. tonsurans developed small, flat, radiating, granular and white-colored colonies with a mahogany-brown reverse side on the fungal culture media. The sequencing of the internal transcribed spacer (ITS) region of the rDNA and the translation elongation factor 1 α (TEF 1 α) gene confirmed the species T. tonsurans in all cases. T. interdigitale that was found from a mat was also identified by sequencing. Eight T. tonsurans strains were subjected to in vitro susceptibility testing to terbinafine. All isolates were sensitive to terbinafine in vitro with minimal inhibitory concentrations of ≤ 0.1 µg/ml.