Fungal interdigital tinea pedis in Dakar (Senegal)

Tinea pedis: an updated review

Background

Tinea pedis is one of the most common superficial fungal infections of the skin, with various clinical manifestations. This review aims to familiarize physicians with the clinical features, diagnosis and management of tinea pedis.

Methods

A search was conducted in April 2023 in PubMed Clinical Queries using the key terms 'tinea pedis' OR 'athlete's foot'. The search strategy included all clinical trials, observational studies and reviews published in English within the past 10 years.

Results

Tinea pedis is most often caused by Trichophyton rubrum and Trichophyton interdigitale. It is estimated that approximately 3% of the world population have tinea pedis. The prevalence is higher in adolescents and adults than in children. The peak age incidence is between 16 and 45 years of age. Tinea pedis is more common amongst males than females. Transmission amongst family members is the most common route, and transmission can also occur through indirect contact with contaminated belongings of the affected patient. Three main clinical forms of tinea pedis are recognized: interdigital, hyperkeratotic (moccasin-type) and vesiculobullous (inflammatory). The accuracy of clinical diagnosis of tinea pedis is low. A KOH wet-mount examination of skin scrapings of the active border of the lesion is recommended as a point-of-care testing. The diagnosis can be confirmed, if necessary, by fungal culture or culture-independent molecular tools of skin scrapings. Superficial or localized tinea pedis usually responds to topical antifungal therapy. Oral antifungal therapy should be reserved for severe disease, failed topical antifungal therapy, concomitant presence of onychomycosis or in immunocompromised patients.

Conclusion

Topical antifungal therapy (once to twice daily for 1-6 weeks) is the mainstay of treatment for superficial or localized tinea pedis. Examples of topical antifungal agents include allylamines (e.g. terbinafine), azoles (e.g. ketoconazole), benzylamine, ciclopirox, tolnaftate and amorolfine. Oral antifungal agents used for the treatment of tinea pedis include terbinafine, itraconazole and fluconazole. Combined therapy with topical and oral antifungals may increase the cure rate. The prognosis is good with appropriate antifungal treatment. Untreated, the lesions may persist and progress.

A Review on Antifungal Efficiency of Plant Extracts Entrenched Polysaccharide-Based Nanohydrogels

Human skin acts as a physical barrier; however, sometimes the skin gets infected by fungi, which becomes more severe if the infection occurs on the third layer of the skin. Azole derivative-based antifungal creams, liquids, or sprays are available to treat fungal infections; however, these formulations show various side effects on the application site. Over the past few years, herbal extracts and various essential oils have shown effective antifungal activity. Additionally, autoxidation and epimerization are significant problems with the direct use of herbal extracts. Hence, to overcome these obstacles, polysaccharide-based nanohydrogels embedded with natural plant extracts and oils have become the primary choice of pharmaceutical scientists. These gels protect plant-based bioactive compounds and are effective delivery agents because they release multiple bioactive compounds in the targeted area. Nanohydrogels can be applied to infected areas, and due to their contagious nature and penetration power, they get directly absorbed through the skin, quickly reaching the skin's third layer and effectively reducing the fungal infection. In this review, we explain various skin fungal infections, possible treatments, and the effective utilization of plant extract and oil-embedded polysaccharide-based nanohydrogels.

[Mycoses and antifungals: What is the situation in Senegal in the current context?]

In the context of increasing incidence of fungal infections worldwide, the availability of antifungal drugs was studied in Senegal, a country with limited resources where diagnosis of invasive fungal infections is not often established by lack of specialists and/or diagnostic tools. After a background on the country's situation with regard to fungal infections and the drug distribution network in Senegal, a compilation of the various available antifungals was presented before concluding with recommendations to prepare for a situation that could allow to treat appropriately invasive mycoses.

A Comparative Study on Phenotypic versus ITS-Based Molecular Identification of Dermatophytes Isolated in Dakar, Senegal

Classically, dermatophytes are identified by phenotypic methods even if these methods, sometimes, remain difficult or uncertain. On the other hand, nucleotide sequence analysis of internal transcribed spacers (ITS) of rDNA has proved to be a useful method for identification of dermatophytes. The objective of this study was to compare the phenotypic method with DNA sequencing of the ITS regions for identification of dermatophyte species isolated in Dakar, Senegal. A collection of thirty-two strains of dermatophytes were isolated from patients suffering from dermatophytosis. Mycological identification revealed Trichophyton soudanense (n = 13), T. interdigitale (n = 10), Microsporum audouinii (n = 5), and one strain for each of the following species: T. rubrum, T. mentagrophytes, and M. canis and one unidentified strain. For comparison, ITS-based PCR and DNA sequencing were applied for identification of the isolated dermatophytes. ITS sequences showed, in BLAST search analysis, 99-100% of similarity. Identification of dermatophyte isolates by conventional methods was confirmed by DNA sequencing of the ITS regions in 84% of cases. Discrepancies concern mostly T. rubrum misidentified as T. interdigitale. PCR sequencing provided an excellent tool for identifying dermatophyte strains that do not present typical morphological characteristics. It was also able to give correct identification of an atypical strain of M. audouinii responsible of mycetoma of the scalp.

Recurrent candidal intertrigo: challenges and solutions

Intertrigo is a common inflammatory dermatosis of opposing skin surfaces that can be caused by a variety of infectious agents, most notably candida, under the effect of mechanical and environmental factors. Symptoms such as pain and itching significantly decrease quality of life, leading to high morbidity. A multitude of predisposing factors, particularly obesity, diabetes mellitus, and immunosuppressive conditions facilitate both the occurrence and recurrence of the disease. The diagnosis of candidal intertrigo is usually based on clinical appearance. However, a range of laboratory studies from simple tests to advanced methods can be carried out to confirm the diagnosis. Such tests are especially useful in treatment-resistant or recurrent cases for establishing a differential diagnosis. The first and key step of management is identification and correction of predisposing factors. Patients should be encouraged to lose weight, followed up properly after endocrinologic treatment and intestinal colonization or periorificial infections should be medically managed, especially in recurrent and resistant cases. Medical treatment of candidal intertrigo usually requires topical administration of nystatin and azole group antifungals. In this context, it is also possible to use magistral remedies safely and effectively. In case of predisposing immunosuppressive conditions or generalized infections, novel systemic agents with higher potency may be required.

Another Case of Interdigital Located "Metastasing Hematoma"?

Interdigital spaces could be an area of affection of a various cutaneous conditions, most of them with benign origin. The spectrum of differential diagnosis of pigmented interdigital lesions with a recent occurrence is not so wide, in contrast. When considering pigmented lesions in the interdigital area, the most harmless differential diagnosis is a traumatic hematoma. But what would happen if we based our therapeutic behaviour or suspicious and unconfirmed harmless diagnosis, instead of considering the real life-threatening once with priority, if we kept in mind that acral lentiginous melanoma has rather an aggressive course and is the main cause of death in skin cancer patients? We present a case of misdiagnosed interdigital melanoma, treated as a hemangioma with curettage, with almost fatal consequences, in regard to uncontrolled tumor progression as a result of the wrong traumatic procedure in one hand, and the lack of adequate screening and follow up, leading to progress of the disease with lymph node metastasis and poor prognosis in general. We want to emphasise the importance of acral lentiginous melanoma with an unusual location in the differential diagnostic plan because, despite the early detection, early eradication with simple excision could save a life, or at least could provide a better prognosis.

Onychomycosis Caused by Fusarium spp. in Dakar, Senegal: Epidemiological, Clinical, and Mycological Study

Fusarium spp. represent 9 to 44% of onychomycoses caused by fungi other than dermatophytes. This retrospective study describes 17 cases of Fusarium onychomycosis diagnosed at the Laboratory of Parasitology and Mycology of Le Dantec University Hospital in Dakar, Senegal, from 2014 to 2016. It included all patients received in the laboratory for suspicion of onychomycosis between January 1, 2014, and December 31, 2016. Diagnosis was based on mycological examination including direct examination and culture. Mycological analysis was considered positive when direct examination and culture were positive after at least one repeat. Seventeen Fusarium onychomycosis cases representing 12.9% of all onychomycoses reported were diagnosed. There were 5 cases on the fingernails and 12 on the toenails in 6 males and 11 females, and the mean age was 44 years (range: 26-64). Onychomycoses were diagnosed in immunocompetent patients except in a diabetic patient. The mean duration of lesions was 4.9 years (range: 1-15), and distal subungual onychomycosis was predominant. Almost all patients were from suburban areas of Dakar region. The most frequent species isolated belong to Fusarium solani complex. Because of the risk of disseminated infection in immunocompromised patients, realization of susceptibility tests is necessary to ensure better therapeutic management.

[Interdigital tinea pedis resulting from Fusarium spp. in Dakar, Senegal]

INTRODUCTION

Fungal interdigital tinea pedis (ITP) is a common pathology mainly due to dermatophytes and yeasts. Fusarium sp. is rarely incriminated in the genesis of intertrigo. In Dakar, a recent study conducted in 2016 on fungal ITP showed that Fusarium were more involved in the etiology of ITP than dermatophytes, coming just after yeasts dominated by Candida. Following this, we wanted to draw attention to the increasing incidence of ITP resulting from Fusarium spp., in Dakar, Senegal, and to analyze the epidemiological and mycological particularities of these ITP due to Fusarium spp.

PATIENTS AND METHODS

A retrospective study including all patients received at the laboratory for suspicion of ITP between January 1st, 2014 and June 30th, 2017 was conducted. Diagnosis was based on mycological examination, including direct examination and culture. Mycological analysis was considered positive when direct examination and culture were positive after at least one repeat.

RESULTS

Twenty-nine cases of Fusarium ITP accounting for 44.6% of all ITP in the study period were diagnosed in 15 men and 14 women. The mean age of the patients was 48.4 years. Fusarium ITP were diagnosed in immunocompetent patients except in two diabetics. The mean duration of the lesions was 6.83 years. The most frequent species isolated belonged to the Fusarium solani complex with 19 cases.

CONCLUSION

Fusarium ITP in a healthy subject requires regular monitoring because any subsequent decrease in immune defenses could lead to fatal hematogenous spread.

[Causative agents of superficial mycoses isolated in Dakar, Senegal: Retrospective study from 2011 to 2015]

INTRODUCTION

Superficial fungal infections, particularly of the skin, scalp and nails are very common and have been reported worldwide. The most common causative agents of these mycoses are dermatophytes, yeasts and molds. However, these agents vary with time and depend on many factors including the geography. The objective of this study was to identify the causative agents of superficial mycoses diagnosed at the Le Dantec University Hospital in Dakar (Senegal).

MATERIAL AND METHODS

The study concerned 1851 outpatients received in the parasitological and mycological laboratory of Le Dantec hospital during the period from January 2011 to December 2015. Every patient benefited from direct examination and mycological culture.

RESULTS

Among the 1851 patients, 633 were confirmed with superficial mycoses and the prevalence was 34.2 %. The age of patients ranged from two months to 81 years with a mean age of 31 years. Superficial mycoses were found more in women (70.3 %) than men (29.7 %) and a little more than thirty-nine percent (39.3 %) were adults. The causative agents identified were: dermatophytes (58 %), yeast (36.7 %) and non-dermatophytic filamentous fungi (NDFF, 5.3 %). The most isolated species were: Candida albicans (26.9 %), Trichophyton soudanense (24.9 %) and T. rubrum (13.7 %). These fungi were responsible for different clinical aspects, isolated and other associated. Among the isolated clinical aspects, those affecting hair (tinea capitis) were by far the largest with 44.8 %, followed by tinea unguium (34.5 %). Associations were especially type of tinea capitis and tinea manuum (2.4 %) and toenails onychomycosis associated with interdigital tinea pedis (2.7 %). Tinea capitis agents were exclusively dermatophytes and the predominant agent was T. soudanense with 47,8 %. Tinea unguium agents were yeast (79 %), dermatophytes (18 %) or NDFF (3 %) and the most found species was C. albicans (63.9 %). Dermatophytes, yeasts and molds were respectively found more in children and young adults, older adults and young adults and older adults and the elderly.

CONCLUSION

In definitive, these epidemiological data should enable better diagnostic and therapeutic management of superficial mycoses.