Examen mycologique en dermatologie.

Dermatomycoses are dermatological infections very commonly encountered in private dermatological practice since they affect up to one third of the population. However, the symptoms are very often shared by other skin infections and disorders and may be highly atypical. It is thus impossible to make a diagnosis with any certainty on clinical grounds alone. For this reason, mycological diagnosis is essential to either confirm or rule out dermatomycosis, and is unavoidable when antifungal therapy is required for the treatment of ringworm of the scalp or beard, or for onychomycosis. It is also vital where therapy guided by the clinical appearance of lesions has failed or in the event of recurring skin lesions. Confirmation of mycosis enables antifungals to be initiated and a negative test warrants investigation for other underlying causes for the lesions seen. However, regardless of the mycological diagnostic technique employed, the quality of the results depends chiefly on the quality of sampling of the infected site, but also on the expertise of the microbiologist. Standard mycological testing remains the most informative, the least expensive and the sole examination capable of isolating the causative fungus irrespective of the type of mycosis, such as dermatophytosis, scytalidiosis, mould-induced ungual infection, candidiasis, or infections due to Malassezia sp. This is the only examination able to identify epidemiological variations. All other more recent techniques are either based upon simple demonstration of the fungal elements involved, without identification of the fungal species in question, or else they are reliant upon a fungal database that is generally highly incomplete.

[Chromomycosis acquired in a non-tropical area: A case report]. / Une chromomycose contractée en zone non tropicale.

BACKGROUND: Chromomycosis, or chromoblastomycosis, is caused by cutaneous inoculation of dematiaceous fungi of telluric or plant origin. It is generally seen in tropical or subtropical zones. Treatment of the condition is known to be complex. Herein we report a case of chromomycosis contracted in a temperate region of Eastern Europe/Central Asia that was effectively treated with oral itraconazole and terbinafine in combination with cryotherapy. PATIENTS AND METHODS: A 44-year-old immunocompetent male subject consulted for a lesion on the buttocks that he had sustained 16 years earlier, and which, although never previously treated, had only become troublesome within the last few months. The examination revealed a large erythemato-squamous plaque containing a heterogeneous infiltrate. The diagnosis was based upon biopsy, with histological examination revealing sooty mould ; culture of a second sample showed the causative agent to be Fonsecaea pedrosoi. After 30 months of treatment combining oral terbinafine at a very high dose (1000mg/day), topical terbinafine and adjuvant cryotherapy, considerable, though incomplete, improvement was obtained. Finally, combined use of terbinafine (500mg/day) and itraconazole (200mg/day) led to clinical and histological cure. DISCUSSION: The possibility of acquiring chromomycosis other than in a tropical zone is slight but has nevertheless been described, particularly in Eastern Europe. In our patient, the exact source of contamination is unknown, although it may have been acquired through frequent horse-riding or use of saunas. This case confirms the efficacy of combined itraconazole and terbinafine against this condition, which is usually difficult to treat.

[Treatment of onychomycosis]. / Traitement des onychomycoses.

A positive mycological examination is required before discussion of treatment of onychomycosis. Onychomycosis is most commonly due to dermatophytes in association with tinea pedis and/or tinea manuum. It is a catched infection. Candida onychomycosis is a rare opportunistic infection and onychomycosis due to non-dermatophytic moulds is very rare as a "chance mishap". The treatment of dermatophyte onychomycosis takes each infected part of the nail into account. Topical antifungal agents should be reserved for mild to moderate onychomycosis. Systemic antifungal agents are required to severe onychomycosis. In all cases, removal of infected nail parts is useful to facilitate the penetration of antifungal drugs and eradication of reinfection sites may be done to prevent recurrences and relapses. In primary, Candida onychomycosis treatment with topical antifungal drugs may be effective but in case of treatment failure, a systemic therapy is required. Suppression predisposing factors is useful. The treatment of non-dermatophytic moulds onychomycosis is still a challenge. Except Neoscytalidium spp., which mimic a dermatophytosis, non-dermatophytic moulds may be isolated from dystrophic nails and it is always difficult to specify their role as a primary pathogen or as a colonizer of nails. The available topical and systemic antifungal drugs are not effective against these non-dermatophytic moulds except itraconazole for onychomycosis due to Aspergillus spp. New therapy such as light and laser therapy are in evaluation.

A study on the decontamination of insoles colonized by Trichophyton rubrum: effect of terbinafine spray powder 1% and terbinafine spray solution 1%.

BACKGROUND: Shoes worn with bare feet function as a fungal reservoir and lead to persistent dermatophytosis. OBJECTIVE: This study was designed to evaluate two formulations of terbinafine (1% spray powder or solution) to treat the insoles of shoes colonized by skin scales infected with Trichophyton rubrum and to determine the contact time necessary to achieve decontamination. METHODS: Infected skin scales weighing 0.5 g, taken from the feet of patients with confirmed T. rubrum infection, was dispersed onto insoles pre-moistened with sterile saline solution (to mimic perspiration). Three types of insole were tested (felt, latex, leather). After inoculation, insoles were placed separately in new cardboard boxes at ambient temperature, and re-humidified with sterile normal saline solution for 48 h before being treated; untreated insoles served as controls. Scales were scraped off at 48 h or 96 h, and dropped into tubes of Sabouraud agar, incubated at 27°C and examined at 3 and 6 weeks. RESULTS: Cultures from all control insoles showed numerous T. rubrum colonies. In contrast, cultures from all insoles treated with a single application of terbinafine 1% spray solution or powder, and taken after 48 h or 96 h contact with the product, remained sterile at 3 weeks and 6 weeks. CONCLUSION: This study demonstrated the successful treatment of insoles colonized by T. rubrum-infected skin scales. Terbinafine 1% spray solution and powder showed good efficacy; the dermatophyte could no longer be cultured 48 h after a single application of terbinafine.

[Epidemiology and management of onychomycosis in private dermatological practice in France]. / Epidémiologie et prise en charge des onychomycoses en pratique dermatologique libérale en France.

BACKGROUND: Increasing prevalence of onychomycosis has been observed in recent years and regular epidemiological studies of the disease are thus necessary. In addition, treatment of onychomycosis by private dermatologists needs to be better understood. This study was carried out to improve knowledge about the epidemiology of onychomycosis and its management in private practice in France. PATIENTS AND METHODS: Four hundred and eighty-five private dermatologists practising throughout France took part in the study. Between September 2001 and December 2002, they collected the following data for each patient with clinically diagnosed onychomycosis: age, gender, concomitant diseases, regular practice of sport, clinical type of onychomycosis, mycological sampling and results, treatment type, monotherapy or combined therapy. RESULTS: Forty-seven percent of patients (i.e. 1826) underwent mycological sampling. In 1200 cases, a fungus was identified. The results for these 1200 patients were as follows: 44% of patients had matrix involvement. Associated diseases were: diabetes (5%), psoriasis (4.5%), immunosuppression (1%) and peripheral vasculopathy (5%). Onychomycosis involved the toes in 88.7% of cases, the fingers in 8.7% and both toes and nails in 2.6%. In the toes, the clinical diagnosis was subungual distal onychomycosis in 74.2% of cases, superficial leuconychia in 11.1%, proximal subungual onychomycosis in 3.3%, and total onychomycodystrophy in 11.4%. In the toes, a dermatophyte was isolated in 84% of cases, yeast in 8% and a mould in 6%. In the fingers, a dermatophyte was isolated in 37% of cases, yeast in 55% and a mould in 8%. Monotherapy was prescribed to 35% of patients and combined therapy in 65%. Oral treatment represented 59% of monotherapies. DISCUSSION: The main results of our study are that dermatologists do not perform any mycological sampling before treating onychomycosis in 53% of cases; in 56% of cases, onychomycosis does not involve the nail matrix; onychomycosis is localized in the toes 10 times more often than in the fingers; the distal subungual clinical form represents more than 70% of cases, in fingers and toes; in the toes, the total onychomycodystrophy clinical form represents 11.4% of cases; dermatologists prescribe monotherapy in 35% of cases, with 59% of these monotherapies comprising an oral treatment, while matrix involvement is present in only 44% of cases. CONCLUSION: Continual medical education efforts must be continued concerning onychomycosis diagnosis and management in accordance with the French Dermatological Society recommendations.

[Malassezia folliculitis: characteristics and therapeutic response in 26 patients]. / Folliculites à Malassezia: Caractéristiques et réponses thérapeutiques chez 26 malades.

BACKGROUND: Malassezia folliculitis is most often described in patients living in hot and humid countries or in immunocompromised patients. Its frequency in France is unknown. We report 26 cases diagnosed at Saint-Louis Hospital between May 2002 and April 2004. The clinical features, the contributing factors, the results of direct mycological examination and/or histology and the efficacy of antifungal treatments were compared to the literature. PATIENTS AND METHODS: The inclusion criteria were the presence of folliculitis on the trunk confirmed by direct microscopy and/or histopathology showing abundant yeast cells in the follicles. RESULTS: Patients comprised 22 men and 4 women (M/F sex ratio: 5: 5) with a mean age of 46 years. Five patients (19%) were immunocompromised. In normal patients, the duration of folliculitis was long with a mean of 61 months. The eruption was typical, with follicular papules and superficial pustules distributed predominantly on the trunk. Itching was frequent (70%). Direct microscopy was more often positive than histology (89% vs 33%). Some sixty-five percent of the patients had been previously treated by topical or systemic antibiotics or anti-acne drugs, which was ineffective in all cases. Cure with topical ketoconazole, oral ketoconazole alone or in combination with topical ketoconazole occurred respectively in 12%, 75% and 75% of patients, but with consistent recurrence within 3 to 4 months after cessation of treatment. DISCUSSION: Malassezia folliculitis is probably misdiagnosed, as suggested by the long time between onset and diagnosis and the high frequency of non-antifungal treatments prescribed. In our study, direct mycological examination provided more effective diagnosis than histology. Treatment is difficult especially because of the high frequency of relapses. CONCLUSION: A diagnosis of Malassezia folliculitis should be considered in young adults or immunocompromised patients with an itching follicular eruption. Further therapeutic trials are needed due to the frequency of relapse.

Epidemiology and clinical classification of onychomycosis.

OBJECTIVES: To review recent data - what is new in the epidemiology of onychomycoses? To identify the most relevant diagnostic criteria for effective therapy. METHODS: The preliminary results of the European Onychomycosis Observatory (EUROO) study were analysed. In this international study, physicians completed questionnaires concerning patient profile and the disease. RESULTS: One of the most interesting novel findings was that sampling requests were often not made [only 3.4% of general physicians (GPs) and 39.6% of dermatologists]. This means that no information about causative agent(s) was available, hindering appropriate treatment choice. Furthermore, contrary to previous findings, 70.7% of participants did not practice sports. Lastly, these preliminary findings showed that treatment strategy depends largely on the type of treating physician, with GPs preferring monotherapy and dermatologists preferring combination therapy. CONCLUSIONS: A consensus was reached that treatment strategy should depend on the severity of nail involvement and the causative fungus. It is thus important to promote the importance of sampling. To simplify the choice of an appropriate treatment, onychomycosis may be divided into just two clinical groups: onychomycosis with and without nail matrix area involvement. However, the distinct clinical findings (number and type of affected nails, multimorbidity, drug interaction, etc.) in each individual case must be taken into account to ensure an appropriate treatment decision.

New diagnostic techniques.

OBJECTIVES: To review current diagnostic strategies. To review alternative diagnostic techniques. RESULTS: The pathogen(s) responsible for onychomycosis must be identified to optimize treatment. Mycological examination is currently the most common diagnostic technique. This typically involves clearing with potassium hydroxide followed by microscopy. This direct test rapidly differentiates between living and dead hyphae. Sensitivity can be enhanced by using dimethyl sulfoxide (DMSO) or stains such as Chlorazol Black E. However, microscopy must always be combined with culture, allowing correct species identification. Accurate diagnosis depends on the expertise of laboratory staff and biologists and on the quality of the nail sample: samples should always be taken from the most proximal infected area. In the absence of experienced mycological laboratories, new laboratory techniques have been developed. Histological analysis by nail plate clipping has been shown to be an easy and efficient method for diagnosis. However, nail clipping is not an optimal technique for fungal culture and a large proportion of nonpathogenic but contaminant moulds can grow on culture medium. Moreover, histological analysis provides no information about causal agent or vitality. In vivo confocal microscopy and flow cytometry are powerful but complicated and costly techniques, making them unsuitable for routine use. Finally, polymerase chain reaction (PCR) (low proportion of positive results) and PCR-restriction fragment length polymorphism (PCR-RFLP) (suitable even for patients receiving antifungals) techniques have been developed. These molecular methods are cost-intensive and require highly skilled staff, meaning they are reserved exclusively for laboratories that process numerous nail samples. CONCLUSION: In conclusion, mycological examination remains the gold standard technique; it provides the most information, at a reasonable cost with little inconvenience to the patient.

Treatment options--development of consensus guidelines.

BACKGROUND: There are currently three main treatment strategies for onychomycosis: topical, oral and combination. Amorolfine nail lacquer appears to be the most effective form of topical monotherapy. However, the best mycological and clinical cure rates are obtained with combination therapy. Combination therapy increases antifungal spectrum, fungicidal activity and safety. New antifungals (triazoles and echinocandins) were recently developed, enabling new protocols. OBJECTIVES: To review available therapies. To design an algorithm for the management of onychomycoses in daily practice. RESULTS: Therapeutic choice should be based on numerous factors including patient's age and health, aetiology, extent of involvement and clinical form. The consensus was that topical monotherapy is recommended when < 50% of the nail is affected without matrix area involvement. Oral monotherapy or combination therapy is indicated when > 50% of the nail, including the matrix area, is involved. Topical treatments should not be used alone when topical drug transport is suboptimal (i.e. when dermatophytoma, onycholysis or spikes are present). Chemical or mechanical removal should also be considered whenever applicable (interruption of drug transport). CONCLUSION: In conclusion, treatment decision-making tools (e.g. an illustrated booklet or CD-ROM presenting each type of onychomycosis and criteria to be considered before selecting treatment regimen) would be valuable supports for the successful treatment of onychomycoses.

Polymorphisms and intronic structures in the 18S subunit ribosomal RNA gene of the fungi Scytalidium dimidiatum and Scytalidium hyalinum. Evidence of an IC1 intron with an His-Cys endonuclease gene.

The fungi Scytalidium dimidiatum (Nattrassia mangiferae synanamorph) and Scytalidium hyalinum are mainly encountered in (sub)tropical areas as plant pathogens and agents of human dermatomycosis. Because the classification and differentiation of these two species is unclear, we studied 22 S. dimidiatum and 15 S. hyalinum isolates in order to identify potential species-specific insertions and polymorphisms in the 18S subunit ribosomal gene. The presence of an IE intron in S. dimidiatum, together with a single polymorphism (A in S. dimidiatum, G in S. hyalinum) in the coding region, allowed us to differentiate these two species in most cases. Moreover, in one S. dimidiatum isolate we found a group IC1 intron containing a putative truncated His-Cys endonuclease gene. This enzyme shows strong similarity to the intronic homing endonuclease of Physarum polycephalum. Based on these results and our previous findings, we propose an evolutionary pathway for 18S rDNA S. dimidiatum insertions, implying independent events.

[Differential diagnosis of onychomycosis]. / Diagnostic différentiel des onychomycoses.

In order to give an effective treatment to a patient with nail disorders, a correct aetiological diagnosis is necessary. Distal and lateral thickening of nail bed and nail plate with onycholysis, deep or superficial leuconychia, melanonychia, paronychia, distal and lateral onycholysis, and total dystrophic onychomycosis are the common physical signs of onychomycosis which represent 50 per cent out of nails disorders. Nail disorders due to cutaneous or general diseases with similar alteration of nail configuration may be confused with onychomycosis. In many cases, an aetiological trend is given by a total body examination of the skin and the mucosa. To diagnose correctly a non fungal nail disorder from an onychomycosis sometimes is a real challenge. According non fungal nail disorder and fungal nail infection may be associated, so a mycological examination and sometimes histopathological examination are very helpful to establish a good diagnosis.

Tinea pedis in European marathon runners.

BACKGROUND: Epidemiological studies suggest that 15% of the population in industrial countries suffer from tinea pedis (athlete's foot) and that persons who do sports are a high-risk population. OBJECTIVE: To investigate the responsibility of dermatophytes in interdigital lesions of the feet in European marathon runners and to identify associated risk factors. SUBJECTS AND METHODS: Runners of the 14th Médoc Marathon (n = 147) were interviewed on risk factors for tinea pedis and underwent physical and mycological examinations. RESULTS: Interdigital lesions of the feet were found in 66 runners (45%). A dermatophyte was isolated in 45 runners (31%), 12 of whom were asymptomatic. Trichophyton interdigitale and T. rubrum accounted for 49% and 35.5%, respectively, of the cases of tinea pedis. Thirty-three (22%) of the 102 runners free of dermatophyte infection had lesions resembling those of tinea pedis. Increasing age and use of communal bathing facilities were predictive of T. rubrum culture. CONCLUSIONS: Marathon runners are at high risk for tinea pedis, but dermatophytes are responsible for only half of the foot lesions found in runners. The existence of asymptomatic carriers calls for prophylactic measures.

[Fungal and bacterial nail infections]. / Infections mycosiques et bactériennes de l'appareil unguéal.

Fungal and bacterial infections are very common causes of nail deformity. The majority of fungal nail infections are caused by dermatophytes. Dermatophytosis result from a human contamination. A dermatophyte is always a pathogenic agent. Very effective drugs are available to treat dermatophyte nail infections. Yeasts of the genus Candida, notably C. albicans are the second most common cause of nail infection. The infections of nails due to Candida and bacteria are related with Candida sp and bacteria which are common commensals of the gastrointestinal tract, vagina or skin. Except C. albicans which is always a pathogen of skin, the other species of Candida and the bacteria could be a commensal of the skin, a colonizer of a dermatological disease or a true pathogen of nail. It is important to consider these different situations. More rarely, environmental moulds, most often known as saprophytic agents, can affect nails. They do not respond to conventional antifungal drugs. So, their diagnosis do not suffer any error. In order to evaluate properly the patient with possible fungal or bacterial infection of nails and also to choice an accurate therapy, the laboratory confirmation is essential. Clinical diagnosis is not sufficient to distinguish an infection of nails from a dermatological disease (psoriasis, traumatism) and to identify the responsible agent.

Genetic diversity among Trichophyton mentagrophytes isolates using random amplified polymorphic DNA method.

Trichophyton mentagrophytes is a common cosmopolitan dermatophyte species composed of two varieties: T. mentagrophytes var. interdigitale (anthropophilic form) and T. mentagrophytes var. mentagrophytes (zoophilic form). We used a random amplified polymorphic DNA (RAPD) method to study the genetic diversity of 46 clinical isolates of the T. mentagrophytes complex collected from 38 patients with different geographical origins (Europe, Africa, South America). The T. mentagrophytes were isolated either from a unique lesion for 31 patients, including two patients living together, or from at least two sites for seven patients. Only one primer of 15 primers tested showed DNA polymorphism in the isolates, producing 23 distinct patterns belonging to three clusters. There was no specific cluster grouping isolates from the same geographical origin. The same pattern is shared by all the four T. mentagrophytes var. mentagrophytes and 13 of 42 T. mentagrophytes var. interdigitale. An identity of strains responsible for several lesions in seven individuals suggests an homogeneous T. mentagrophytes population in the case of multiple lesions. In contrast, the dissimilarity of two strains recovered from two patients living together argues against person-to-person transmission in that case. This study indicates that RAPD can be successfully applied to show genetic diversity among T. mentagrophytes isolates.

Ivermectin-responsive crusted scabies in HTLV1 carrier.

We report a case of HTLV1 infection revealed by crusted scabies and widespread dermatophytosis in an African woman. HTLV1 infection was not complicated by adult T cell leukemia or myelopathy. Crusted scabies is a marker of HTLV1 infection. The importance of oral ivermectin therapy in crusted scabies is emphasized.

[Contamination by aspergillosis: evaluation of preventive measures and monitoring of the environment]. / Contamination aspergillaire: évaluation des mesures de prévention et surveillance de l'environnement.

Aspergillosis has become a major fungal infection in hospitals since the advent of immunosuppressive therapy in the last fifteen years. Aspergilli are saprophytic and ubiquitous fungi and are associated with pulmonary and disseminated infections in immunodepressed patients with a mortality rate of about 85%. Aspergillosis is an air-borne infection, thus intensive care units should be conceived so as to decrease the outer risk of contamination. In the first part of this chapter the conception of such a unit is presented, taking the bone marrow transplantation unit of St-Louis Hospital as an example. A prospective study of the quality of the environment is a complementary and necessary information. In the second part of this chapter, the methods of airborn control of Aspergillus sp. are investigated. According to the literature, commun concepts can be drawn to evaluate nosocomial risks of aspergillosis. Nevertheless in the absence of a defined and accepted methodology, it is not possible up to that date to propose norms and acceptable norms of levels of contamination adapted to the degree of immunodepression of patients.