Combined distal and lateral subungual and white superficial onychomycosis in the toenails

Global prevalence of onychomycosis in general and special populations: An updated perspective

BACKGROUND

Onychomycosis is a chronic nail disorder commonly seen by healthcare providers; toenail involvement in particular presents a treatment challenge.

OBJECTIVE

To provide an updated estimate on the prevalence of toenail onychomycosis.

METHODS

We conducted a literature search using PubMed, Embase and Web of Science. Studies reporting mycology-confirmed diagnoses were included and stratified into (a) populations-based studies, and studies that included (b) clinically un-suspected and (c) clinically suspected patients.

RESULTS

A total of 108 studies were included. Based on studies that examined clinically un-suspected patients (i.e., with or without clinical features suggestive of onychomycosis), the pooled prevalence rate of toenail onychomycosis caused by dermatophytes was 4% (95% CI: 3-5) among the general population; special populations with a heightened risk include knee osteoarthritis patients (RR: 14.6 [95% CI: 13.0-16.5]), chronic venous disease patients (RR: 5.6 [95% CI: 3.7-8.1]), renal transplant patients (RR: 4.7 [95% CI: 3.3-6.5]), geriatric patients (RR: 4.7 [95% CI: 4.4-4.9]), HIV-positive patients (RR: 3.7 [95% CI: 2.9-4.7]), lupus erythematosus patients (RR: 3.1 [95% CI: 1.2-6.3]), diabetic patients (RR: 2.8 [95% CI: 2.4-3.3]) and hemodialysis patients (RR: 2.8 [95% CI: 1.9-4.0]). The prevalence of onychomycosis in clinically suspected patients was significantly higher likely due to sampling bias. A high degree of variability was found in a limited number of population-based studies indicating that certain pockets of the population may be more predisposed to onychomycosis. The diagnosis of non-dermatophyte mould onychomycosis requires repeat sampling to rule out contaminants or commensal organisms; a significant difference was found between studies that performed single sampling versus repeat sampling. The advent of PCR diagnosis results in improved detection rates for dermatophytes compared to culture.

CONCLUSION

Onychomycosis is an underrecognized healthcare burden. Further population-based studies using standardized PCR methods are warranted.

Onychomycosis due to Fusarium species in different continents, literature review on diagnosis and treatment

Fusarium species are an emerging cause of onychomycosis, and the number of cases has dramatically increased in recent decades worldwide. This review presents an overview of the onychomycosis cases caused by Fusarium species and diagnosis and treatment that have been reported in the literature. The most common causative agent of onychomycosis is F. solani species complex, which accounts for 11.68% of the cases of Fusarium onychomycosis, followed by the F. oxysporum species complex (164 out of 1669), which is accounted for 9.83% of the total. F. fujikuroi species complex (42 out of 1669) and F. dimerum species complex (7 out of 1669) are responsible for 2.52% and 0.42 cases, respectively. Fusarium nail infections were reported in patients aged range 1-98, accounting for 5.55% (1669 out of 30082) of all cases. Asia has the highest species diversity of Fusarium onychomycosis (31.51%). South America accounts for 21.09%, and the most common causative agent is F. solani (19.32%), followed by F. oxysporum species complex (15.63%). Europe accounts for 4.90% of cases caused by F. oxysporum, followed by F. solani. Africa accounts for 23.87% of the cases due to the F. solani species complex, followed by F. oxysporum and F. fujikuroi. Distal and lateral subungual onychomycosis was the most common clinical symptom accounting for 58.7% (135 out of 230) of the cases. Data analysis relieved that terbinafine and itraconazole are active treatments for Fusarium onychomycosis. For a definitive diagnosis, combining of direct examination, culture and sequencing of the elongation factor of translation 1α are recommended. Accurate identification of the causative agents of onychomycosis due to Fusarium species and antifungal susceptibility testing is essential in patient management.

Nondermatophyte mould onychomycosis

Nondermatophyte moulds (NDMs) onychomycosis is often difficult to diagnose as NDMs have been considered contaminants of nails. There are several diagnostic methods used to identify NDMs, however, repeated laboratory isolation is recommended to validate pathogenicity. With NDM and mixed infection (dermatophytes plus NDM) onychomycosis on the rise, accurate clinical diagnosis along with mycological tests is recommended. Systemic antifungal agents such as itraconazole and terbinafine (e.g. pulse regimen: 1 pulse = every day for one week, followed by no treatment for three weeks) have shown efficacy in treating onychomycosis caused by various NDMs such as Aspergillus spp., Fusarium spp., Scopulariopsis brevicaulis, and Onychocola canadensis. Studies investigating topical therapy and devices for NDM onychomycosis are limited. The emergence of antifungal resistance necessitates the incorporation of antifungal susceptibility testing into diagnosis when possible, for the management of recalcitrant infections. Case studies documented in the literature show newer azoles such as posaconazole and voriconazole as sometimes effective in treating resistant NDM onychomycosis. Treatment with broad-spectrum antifungal agents (e.g. itraconazole and efinaconazole) and other combination therapy (oral + oral and/or oral + topical) may be considerations in the management of NDM onychomycosis.

High prevalence of superficial white onychomycosis by Trichophyton interdigitale in a Japanese nursing home with a geriatric hospital

A mycological survey on feet was performed in a nursing home with a geriatric hospital to ascertain the prevalence of tinea lesions. Of 100 subjects, comprising 62 in the nursing home and 38 in the geriatric wing, 70 were diagnosed with tinea pedis, tinea unguium (onychomycosis) or both of which 54 had onychomycosis alone, nine tinea pedis alone and seven had co-existing onychomycosis and tinea pedis. The most common clinical type of onychomycosis was distal lateral subungual onychomycosis (DLSO) at 30 cases, followed by superficial white onychomycosis (SWO) at 23 cases. Fifteen strains of Trichophyton (T.) interdigitale isolated from 23 SWO patients comprised six molecular types (D2II, nine cases; C2II, two cases; four other types, one case of each), based on the non-transcribed spacer region (NTS) of the ribosomal DNA. The pathogen of three other SWO cases was identified as T. rubrum. Direct physical contact between the subjects was unlikely because they were bedridden most of the time. Nine T. interdigitale strains were isolated from a bathtub used by patients on the floor with a high incidence of SWO alone, and all nine strains were D2II type, which suggests nosocomial infection. Consequently, the hospital infection control policy committee was consulted, bathing arrangements were changed, and nursing staff were educated about onychomycosis.

The nondermatophyte molds: Emerging as leading cause of onychomycosis in south-east Rajasthan

Background:

Onychomycosis is a fungal disease of the nail apparatus caused by both dermatophytic and nondermatophytic strains. Treatment involves long duration antifungal therapy. However, long treatment duration without identifying the causative species may lead to resistance. Confirmation of diagnosis and speciation by culture before administering antifungal therapy is ideal.

Aims:

To study the clinical and epidemiological aspects of onychomycosis in Hadoti region (south-east Rajasthan) and identify various mycological strains and predisposing factors causing onychomycosis.

Materials and Methods:

A prospective study of clinically diagnosed cases of onychomycosis attending the outpatient Department of Dermatology in our institute conducted from June 2012 to May 2013. The clippings were subjected to potassium hydroxide (KOH) examination and culture in the appropriate medium.

Results:

A total of 150 cases were enrolled in our study. There were 110 males (73.33%) and 40 females (26.66%) and male to female ratio was 2.75:1. The total dystrophic onychomycosis was the most common presentation seen in the majority of cases (46%) followed by distal lateral subungual onychomycosis in 52 cases (34.6%), mixed onychomycosis in 16 cases (10.66%), superficial white onychomycosis in 11 cases (7.33%), and proximal subungual onychomycosis in 2 cases. None had the endonyx variant. Direct microscopic examination of the nail clipping mounted with 40% KOH demonstrated fungal elements in 83 (55.33%) cases. Rate of isolation of organisms by culture was 64%. Nondermatophytes were isolated in 53 (35.33%), dermatophytes in 28 (18.66%), and yeasts in 15 (10%) of cases. The most commonly isolated species was Aspergillus in 45 (30%) cases. Aspergillus flavus was more commonly isolated compared to Aspergillus niger.

Conclusion:

The nondermatophyte molds appear to be more common causative agents of onychomycosis compared to usual dermatophyte species in south-east Rajasthan. Our study re-emphasizes the importance of culture for diagnosis of onychomycosis in every suspected case prior to therapy.

Superficial white onychomycosis—A syndrome with different fungal causes and paths of infection

Superficial white onychomycosis (SWO) is a clinical term used to describe onychomycosis in which the invasion of the nail plate occurs from the dorsal surface. However, recent observations indicate that the clinical appearances may vary to include infection in patches or in a striate patter. This report shows that, in some cases, it may be combined with either distal and lateral subungual onychomycosis or proximal white subungual onychomycosis. Invasion of the dorsal nail surface, but originating from the proximal nail fold, is another route of infection in SWO. A new classification of this condition is proposed with 4 main variants. Although based on clinical features, often other factors such as immunosuppression or invading organism (eg, Trichophyton rubrum or Fusarium species) appear to play a role in the development of a particular pattern of infection. This is an observational study carried out by trained and experienced clinicians. The main clinical implication is that in combined forms, or where the infection emerges from beneath the proximal nailfold, systemic rather than topical antifungal therapy is advised.

Acremonium Vertebral Osteomyelitis: Molecular Diagnosis and Response to Voriconazole

We present a case of Acremonium vertebral osteomyelitis that relapsed despite surgical debridement and prolonged treatment with liposomal amphotericin B, but which responded to voriconazole therapy. The report highlights the role of molecular diagnosis of rare fungal osteomyelitis. The patient was successfully treated with voriconazole.

Activation of prothrombin by two subtilisin-like serine proteases from Acremonium sp

Two novel subtilisin-like serine proteases (AS-E1 and -E2) that activate prothrombin have been identified in a culture of the fungus Acremonium sp. The enzymes were purified through repeated hydrophobic interaction chromatography. The N-terminal sequences of AS-E1 (34.4 kDa) and AS-E2 (32 kDa) showed high similarity to the internal sequences of two distinct subtilisin-like hypothetical proteins from Chaetomium globosum. Both enzymes proteolytically activated prothrombin to meizothrombin(desF1)-like molecules, while the activation cleavage seemed to occur at a site (Tyr(316)-Ile(317)) that is four residues proximal to the canonical Xa cleavage site (Arg(320)-Ile(321)). Both enzymes inhibited plasma clotting, possibly due to extensive degradation of fibrinogen and production of meizothrombin(desF1)-like molecule.

Diagnosis of fusariosis in urine cytology

Fusarium is a filamentous fungus widely distributed in plants and in the soil. Most species are more common at tropical and subtropical areas. Besides being a common contaminant and a well-known plant pathogen, Fusarium sp may cause various infections in humans. However, it has not yet been reported as being the pathogen of urinary tract infection. A 67-year-old woman had extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy for renal stones 7 and 6 years ago, respectively. She had had fever, chillness, urinary urgency and frequency for 6 days. Routine testing of urine showed numerous leucocytes. She was admitted under the impression of urinary tract infection. On admission, many spindle-shaped structures were found in the urine smears. This shows that Fusarium was identified. Fusarium may be the pathogen of the urinary tract infection, particularly when urolithiasis is present.

Fusarium dimerum as a cause of human eye infections

Fusarium dimerum, typically a soil fungus, was isolated from an adult male suffering from a corneal ulcer following an injury to the eye. This fungus has not been described to cause human infections in South Africa and has not been recorded from soil, plant or organic material in this country. The macro- and microscopic characteristics of the isolate were found to be indistinguishable from described strains. Its authenticity was confirmed by comparing it to other human isolates from the eye obtained in the USA, thus rendering this the first report of F. dimerum from an eye infection in a human in South Africa.

Utility of inoculum counting (Walshe and English criteria) in clinical diagnosis of onychomycosis caused by nondermatophytic filamentous fungi

Opportunistic onychomycosis caused by nondermatophytic molds may differ in treatment from tinea unguium. Confirmed diagnosis of opportunistic onychomycosis classically requires more than one laboratory analysis to show consistency of fungal outgrowth. Walshe and English in 1966 proposed to extract sufficient diagnostic information from a single patient consultation by counting the number of nail fragments positive for inoculum of the suspected fungus. Twenty fragments were plated per patient, and each case in which five or more fragments grew the same mold was considered an infection by that mold, provided that compatible filaments were also seen invading the nail tissue by direct microscopy. This widely used and often recommended method has never been validated. Therefore, the validity of substituting any technique based on inoculum counting for conventional follow-up study in the diagnosis of opportunistic onychomycosis was investigated. Sampling of 473 patients was performed repeatedly. Nail specimens were examined by direct microscopy, and 15 pieces were plated on standard growth media. After 3 weeks, outgrowing dermatophytes were recorded, and pieces growing any nondermatophyte mold were counted. Patients returned on two to eight additional occasions over a 1- to 3-year period for similar examinations. Onychomycosis was etiologically classified based on long-term study. Opportunistic onychomycosis was definitively established for 86 patients. Counts of nondermatophyte molds in initial examinations were analyzed to determine if they successfully predicted both true cases of opportunistic onychomycosis and cases of insignificant mold contamination. There was a strong positive statistical association between mold colony counts and true opportunistic onychomycosis. Logistic regression analysis, however, determined that even the highest counts predicted true cases of opportunistic onychomycosis only 89.7% of the time. The counting criterion suggested by Walshe and English was correct only 23.2% of the time. Acremonium infections were especially likely to be correctly predicted by inoculum counting. Inoculum counting could be used to indicate a need for repeat studies in cases of false-negative results from laboratory direct microscopy. Inoculum counting cannot serve as a valid substitute for follow-up study in the diagnosis of opportunistic onychomycosis. It may, nonetheless, provide useful information both to the physician and to the laboratory, and it may be especially valuable when the patient does not present for follow-up sampling.

Ciclopirox nail lacquer solution 8% in the 21st century

Ciclopirox nail lacquer solution 8% has been shown to be effective in the treatment of dermatophyte onychomycosis of mild to moderate severity Other studies report the effectiveness of ciclopirox nail lacquer in onychomycosis caused by Candida sp and nondermatophyte molds. Ciclopirox nail lacquer may also be valuable in the treatment of early cases of reinfection/relapse. Ciclopirox nail lacquer solution 8% may be an important adjunct to oral antifungal therapy in certain presentations that might be poorly responsive to oral antifungal therapy alone (eg, lateral onychomycosis, longitudinal spike, dermatophytoma, and extensive onycholysis). In some cases, surgical therapies may need to be considered in addition to, or in preference to, topical nail lacquer treatment. The use of ciclopirox nail lacquer solution 8% as an adjunct to oral antifungal therapy may widen the spectrum of activity of the combination because of the broad spectrum of coverage provided by the lacquer. The use of combination therapy may be synergistic in terms of efficacy, enabling a reduction in the duration and cumulative dosage of oral therapy. This could result in a decrease in the frequency and severity of systemic adverse effects associated with the oral antimycotics and the need to be vigilant about drug interactions. Studies need to be conducted to determine the place of combination oral and topical lacquer therapy in the management of onychomycosis.