Mycology - an update Part 3: Dermatomycoses: topical and systemic therapy

Common diseases of the nail: Diagnosis and therapy

This review focuses on nail changes that do not belong to the group of benign or malignant nail tumors. These common afflictions of the nail include structural changes in and under the nail plate as well as inflammation around and in the nail bed. They include onychomycoses, nail psoriasis, onychodystrophies, subungual hematoma, paronychia, ingrown nails and pincer nails. Due to the peculiar anatomy and physiological growth conditions of the nail, the pathology does not necessarily stem from the site of the clinical problem and calls for careful inspection and interpretation.

In vitro activities of 8 antifungal agents against geophilic dermatophyte isolates

BACKGROUND

Members of the Nannizzia gypsea complex are globally the most common geophilic dermatophytes which cause infection in animals and human. Although the susceptibility patterns of anthropophilic or zoophilic dermatophyte species to antifungal agents are well documented, the effectiveness of such drugs against geophilic species have rarely been explored.

OBJECTIVES

This study was aimed to evaluate the in vitro antifungal activity of common and new antifungals against a set of environmental and clinical geophilic dermatophyte isolates.

METHODS

108 soil and clinical geophilic isolates from two genera Nannizzia (N. fulva n = 59; N. gypsea n = 43) and Arthroderma (A. quadrifidum n = 4; A. gertleri n = 1; A. tuberculatum n = 1) were included in the study. The in vitro antifungal susceptibility patterns of eight common and new antifungals against the isolates were determined according to broth microdilution method and by CLSI M38-A3 (3rd edition) protocol.

RESULTS

MIC values across all isolates from five species ranged as: luliconazole: 0.0002-0.002 µg/ml, terbinafine: 0.008-0.125 µg/ml, efinaconazole: 0.008-0.125 µg/ml, ciclopirox olamine: 0.03-0.5 µg/ml, itraconazole: 0.125-1 µg/ml, amorolfine hydrochloride: 0.125-4 µg/ml, griseofulvin: 0.25-2 µg/ml and tavaborole: 1-8 µg/ml, respectively.

CONCLUSION

Luliconazole, terbinafine and efinaconazole exhibited the highest in vitro efficacy, regardless of the dermatophyte species. Further surveillance studies are recommended to confirm the implication of such in vitro data for the clinical recovery rate of dermatophytosis with geophilic species following antifungal therapy.

[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.

[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.

Prospective Nanotechnology-Based Strategies for Enhanced Intra- and Transdermal Delivery of Antifungal Drugs

Topical therapy of superficial fungal infections allows the prevention of systemic side effects and provides drug targeting at the site of disease. However, an appropriate drug concentration in these sites should be provided to ensure the efficacy of such local treatment. The enhancement of intra- and transdermal penetration and accumulation of antifungal drugs is an important aspect here. The present overview is focused on novel nano-based formulations served to improve antimycotic penetration through the skin. Furthermore, it summarizes various approaches towards the stimulation of drug penetration through and into the stratum corneum and hair follicles, which are considered to be promising for the future improvement of superficial antifungal therapy as providing the drug localization and prolonged storage property at the targeted area.

Updates on Genital Dermatophytosis

Dermatophytes are a group of keratinophilic fungi, which normally cause superficial infection of skin, hair and nails. Based on ecology, they are classified into three groups: anthropophilic, zoophilic and geophilic. Superficial dermatophytic infection of the genital region is called genital dermatophytosis, tinea genitalis or pubo-genital dermatophytosis. In this review, we would like to discuss briefly, the various clinical presentations of genital dermatophytosis, current changes in the taxonomy and nomenclature, introduction of new diagnostic techniques and briefly describe some common dermatophytes and their sources. Also, there are serious concerns associated with the recent development of antifungal resistance among the dermatophytes. We are also facing the scenario of hard-to-treat dermatophytosis.

[Do the new molecular assays-microarray and realtime polymerase chain reaction-for dermatophyte detection keep what they promise?]

In this study, a novel real-time polymerase chain reaction (PCR) assay (DermaGenius®2.0, PathoNostics BV, Maastricht, The Netherlands) and a recently developed microarray test (EUROArray Dermatomycosis, Euroimmun, Lübeck, Germany) were evaluated regarding their diagnostic specificity to identify dermatophyte DNA. The tests were compared to conventional methods and sequencing. The microarray Dermatomycosis test allows the detection of 50 dermatophytes and definitive identification of 23 dermatophyte species, 6 yeasts and moulds combined in one test. In comparison, real-time PCR is able to identify 11 dermatophytes and one yeast at the species level. Using the EUROArray, 22 out of 24 dermatophyte species were correctly identified. Using real-time PCR, 9 out of the 11 different dermatophytes included in the test kit were correctly identified. Both molecular tests for detection and differentiation of dermatophytes are useful tools for daily clinical practice. The real-time PCR test does not detect as many species, and specificity is slightly lower. However, real-time PCR is a very fast and easy to perform test, especially since no post-PCR step is necessary. Real-time PCR detects the most frequent dermatophytes like T. rubrum, T. interdigitale, and M. canis without any problems. The EUROArray is more elaborate to perform in the lab, due to the hybridization step. However, the EUROArray shows higher specificity and can detect a much broader range of causative agents, including rare species, in dermatomycology.

[Tinea barbae profunda due to Trichophyton mentagrophytes after journey to Thailand : Case report and review]

Tinea barbae represents a very rare dermatophytosis. We report on a tinea barbae profunda following a journey to Southeast Asia. After travel to Thailand, a businessman was affected by a foudroyant proceeding abscessing infection of the upper lip and beard area. The initial therapy with oral acyclovir and oral ciprofloxacin, which later was changed to ampicillin plus sulbactam, intravenously, was unsuccessful. In a biopsy sample, histologically, with Grocott-Gomori's methenamine silver stain, fungal mycelium was apparent in the tissue. Thereupon, terbinafine 250 mg was given for 4 weeks, topically, a 1% ciclopiroxolamine-containing cream. In fungal culture, T. mentagrophytes were found to grow. Meanwhile, the patient's German wife suffered from a tinea faciei. From skin scrapings from the cheek, T. mentagrophytes was also cultivated. This zoophilic dermatophyte was identical with other zoophilic strains of T. mentagrophytes currently found in Germany, which were also acquired in Thailand. The patient had contact with Thai female sex workers who must be considered as a source of infection of the dermatophytosis. There was no animal contact, neither in Thailand, nor in Germany. The infection chain of the dermatophytosis from Thailand probably reached from a female sex worker via the here described patient to his wife in Germany. This pathway of infection has been known for 1 or 2 years, but until now, in Germany, Switzerland, and Austria exclusively via pubogenital infections (tinea genitalis profunda) due to T. mentagrophytes after journeys to Southeast Asia. For treatment, oral antifungal agents should be used, first of all terbinafine, alternatively fluconazole or itraconazole.

[Tinea barbae profunda due to Trichophyton mentagrophytes : Case report and review]

Tinea barbae is a rare dermatomycocis, by definition follicular bound in the beard area of adult men. Manifestation usually starts with erythema accompanied by desquamation. Deeper distribution along terminal hairs leads to folliculitis with formation of pustules and nodes as well as abscesses; fixed adherent yellowish crusts may appear. Frequently there is locoregional swelling of the lymph nodes and occasionally a deterioration of general condition with (sub)febrile temperatures. Often this leads to the initial suspected diagnosis of a bacterial folliculitis barbae or impetigo contagiosa. Tinea barbae is mostly induced by species of the genus Trichophyton (T.). The pathogens are diverse and are mostly zoophilic, sometimes anthropophilic and rarely geophilic dermatophytes. With the help of a specific anamnesis and diagnostic procedure, including mycological examinations, histology and molecular detection of dermatophytes via polymerase chain reaction (PCR), tinea barbae-in our patient induced by T. mentagrophytes-can be rapidly diagnosed. Early initiation and adequate treatment duration lead to restitutio ad integrum.

Expert Consensus on The Management of Dermatophytosis in India (ECTODERM India)

Background

Dermatophytosis management has become an important public health issue, with a large void in research in the area of disease pathophysiology and management. Current treatment recommendations appear to lose their relevance in the current clinical scenario. The objective of the current consensus was to provide an experience-driven approach regarding the diagnosis and management of tinea corporis, cruris and pedis.

Methods

Eleven experts in the field of clinical dermatology and mycology participated in the modified Delphi process consisting of two workshops and five rounds of questionnaires, elaborating definitions, diagnosis and management. Panel members were asked to mark “agree” or “disagree” beside each statement, and provide comments. More than 75% of concordance in response was set to reach the consensus.

Result

KOH mount microscopy was recommended as a point of care testing. Fungal culture was recommended in chronic, recurrent, relapse, recalcitrant and multisite tinea cases. Topical monotherapy was recommended for naïve tinea cruris and corporis (localised) cases, while a combination of systemic and topical antifungals was recommended for naïve and recalcitrant tinea pedis, extensive lesions of corporis and recalcitrant cases of cruris and corporis. Because of the anti-inflammatory, antibacterial and broad spectrum activity, topical azoles should be preferred. Terbinafine and itraconazole should be the preferred systemic drugs. Minimum duration of treatment should be 2–4 weeks in naïve cases and > 4 weeks in recalcitrant cases. Topical corticosteroid use in the clinical practice of tinea management was strongly discouraged.

Conclusion

This consensus guideline will help to standardise care, provide guidance on the management, and assist in clinical decision-making for healthcare professionals.

COMBINATION ANTIFUNGAL THERAPY FOR ONYCHOMYCOSIS

Onychomycosis is a fungal infection of the nail unit including the nail matrix, the nail bed and the nail plate by both dermatophyte and non-dermatophyte agents. It is disturbs not only cosmetic disfigurement, but also it may have an impact on patients’ emotional, social and occupational functioning, finally affecting the overall quality of life. The incidence rate tends to increase, management of onychomycosis is still challenging. Important problems regarding antifungal monotherapy have experienced many failures and recurrences. In general, pharmacological approaches for onychomycosis can be topical or oral antifungal. Antifungal monotherapies often lead to failure treatment, also high incidence of recurrence. One strategy for this problem is a combination antifungal therapy. In vitro studies show the synergistic effect of using combination two antifungals (both oral antifungal or combination topical and oral antifungal), hence it is mycologically or clinically expected to increase the success rate of onychomycosis therapy. This review tries to evaluate the previous study exploring the effectiveness of antifungal combination therapies on onychomycosis. Two oral antifungals usually used are terbinafine as fungicidal agent and itraconazole as fungistatic agent. There is combination between topical and oral antifungal such as itraconazole or terbinafine with amorolfine or ciclopirox, also other combination like griseofulvin and amorolfone or tioconazole. All the combination therapies show better result than monotherapy alone, but it is still difficult to conclude whether antifungal combinations in onychomycosis will increase effectiveness due to variations in therapeutic duration, result definition, and statistical evaluation on existing studies. Further research is required with longer duration of observation, uniform patient criteria and definition of success, random control and blinding to minimize bias.

The Diagnosis and Treatment of Nail Disorders

BACKGROUND

Nail disorders can arise at any age. About half of all nail disorders are of infectious origin, 15% are due to inflammatory or metabolic conditions, and 5% are due to malignancies and pigment disturbances. The differential diagnosis of nail disorders is often an area of uncertainty.

METHODS

This review is based on publications and guidelines retrieved by a selective search in PubMed, including Cochrane reviews, meta-analyses, and AWMF guidelines.

RESULTS

Nail disorders are a common reason for derma - tologic consultation. They are assessed by clinical inspection, dermatoscopy, diagnostic imaging, microbiological (including mycological) testing, and histopathological examination. Some 10% of the overall population suffers from onychomycosis, with a point prevalence of around 15%. Bacterial infections of the nails are rarer than fungal colonization. High-risk groups for nail disorders include diabetics, dialysis patients, transplant recipients, and cancer patients. Malignant tumors of the nails are often not correctly diagnosed at first. For subungual melanoma, the mean time from the initial symptom to the correct diagnosis is approximately 2 years; this delay is partly responsible for the low 10-year survival rate of only 43%.

CONCLUSION

Evaluation of the nail organ is an important diagnostic instrument. Aside from onychomycosis, which is a common nail disorder, important differential diagnoses such as malignant diseases, drug side effects, and bacterial infections must be considered.

[Onychocola canadensis Sigler in onychomycosis : A new dermatophyte-like mould in Germany]

Moulds or non-dermatophyte moulds (NDM) are being increasingly isolated as causative agent of onychomycoses. Known causes of a NDM-OM are Scopulariopsis brevicaulis, Fusarium, Aspergillus, Acremonium, Neoscytalidium dimidiatum, Arthrographis kalrae, and Chaetomium. In this article, 5 patients with suspected nail infection due to Onychocola canadensis are reported for the first time in Germany. Systemic antifungal agents are not considered to be effective in NDM onychomycosis. In individual cases, however, terbinafine seems to be effective in Onychocola canadensis infection of the nails. Treatment of choice represents, however, nontraumatic nail avulsion using 40 % urea ointment followed by antifungal nail lacquer with ciclopirox olamine or amorolfine.

[Microsporum canis: Current data on the prevalence of the zoophilic dermatophyte in central Germany]

BACKGROUND

Microsporum (M.) canis, whose source of infection is mostly cats, is still considered as the most frequently occurring zoophilic dermatophyte in Germany and Europe. In distinct areas of Germany, the zoophilic dermatophyte Trichophyton (T.) anamorph of Arthroderma (A.) benhamiae also presents a frequent and emerging causative agent of dermatophytoses.

MATERIALS AND METHODS

Over a period of 3 years, from March 2010 to March 2013, skin samples from scalp, face, trunk, and limbs were investigated using mycological cultivation and by polymerase chain reaction (PCR) for dermatophytes. Materials originated in particular from the German Free States Saxony and Thuringia, and from the Federal State Saxony-Anhalt, but also included samples submitted from around Germany. The cultural detection of dermatophytes was performed on Sabouraud's 4% glucose agar with and without cycloheximide. For dermatophyte DNA detection, a uniplex PCR-ELISA was used.

RESULTS

In all, 8464 samples from a total of 7680 patients were investigated. In 114 (1.5%) of 7680 patients, M. canis could be detected both by culture and/or PCR. M. canis was detected culturally in 100 samples, in 107 samples by PCR, in 91 samples both culturally and by PCR. For 12 patients, only cultural detection was done (without PCR). Also detected was tinea corporis due to M. canis in 59 patients, tinea capitis 8, tinea faciei 5, and tinea manus 2 patients. Of the patients, 45% were younger than 20 years, 42% were 20-49 years old, and 13% were 50 years or older. In comparison, T. anamorph of A. benhamiae was detectable by culture and/or PCR in 231 of 7680 patients (2.9%). M. canis was the second most common zoophilic dermatophyte.

CONCLUSIONS

M. canis is still a frequent zoophilic dermatophyte in Germany. Since a few years ago, a rise of infections due to T. anamorph of A. benhamiae has been observed in Germany and other European countries. At least in distinct regions of Germany, this zoophilic dermatophyte, which is transferred from guinea pigs to human beings, currently seems to be more frequent when compared to M. canis.