Proximal subungual onychomycosis due to Aspergillus niger: report of two cases

Onychomycosis: Old and New

Onychomycosis is a common chronic fungal infection of the nail that causes discoloration and/or thickening of the nail plate. Oral agents are generally preferred, except in the case of mild toenail infection limited to the distal nail plate. Terbinafine and itraconazole are the only approved oral therapies, and fluconazole is commonly utilized off-label. Cure rates with these therapies are limited, and resistance to terbinafine is starting to develop worldwide. In this review, we aim to review current oral treatment options for onychomycosis, as well as novel oral drugs that may have promising results in the treatment of onychomycosis.

Aspergillus Genus and Its Various Human Superficial and Cutaneous Features

Superficial and cutaneous aspergillosis is a rare fungal disease that is restricted to the outer layers of the skin, nails, and the outer auditory canal, infrequently invading the deeper tissue and viscera, particularly in immunocompromised patients. These mycoses are acquired through two main routes: direct traumatic inoculation or inhalation of airborne fungal spores into paranasal sinuses and lungs. Lesions are classified into three categories: otomycosis, onychomycosis, and cutaneous aspergillosis. Superficial and cutaneous aspergillosis occurs less frequently and therefore remains poorly characterized; it usually involves sites of superficial trauma-namely, at or near intravenous entry catheter site, at the point of traumatic inoculation (orthopaedic inoculation, ear-self-cleaning, schizophrenic ear self-injuries), at surgery incision, and at the site of contact with occlusive dressings, especially in burn patients. Onychomycosis and otomycosis are more seen in immunocompetent patients, while cutaneous aspergillosis is widely described among the immunocompromised individuals. This paper is a review of related literature.

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.

Subungual onychomycosis due to Aspergillus niger mimicking a glomus tumor: A case report

Onychomycosis is a common nail infection caused by dermatophytes, while non-dermatophytes including Aspergillus spp. are causes of nail onychomycosis. Aspergillus niger is not common as a cause of nail onychomycosis. In the current study we present a 60-year-old woman with subungual onychomycosis due to Aspergillus niger mimicking a glomus tumor. Physical examination revealed right thumb had a black color of nail bed. Localized tenderness and severe pain were observed. However, the cold sensitivity test, Loves pin test and Hildreths test were negative. On radiograph, bone erosion was found in a part of distal phalanx at the right thumb. Magnetic resonance imaging identified a mass at the subungual space, which exhibited low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. The differential diagnosis included glomus tumor and infection. The histological findings demonstrated dichotomous septate hyphae. The culture was positive for Aspergillus niger. The results suggested that when physical examination is not typical for a glomus tumor, other diseases may be considered. Additionally, frozen section diagnosis may be useful.

Itraconazole and Terbinafine Treatment of Some Nondermatophyte Molds Causing Onychomycosis of the Toes and a Review of the Literature

Background:

Onychomycosis may be caused by dermatophytes (which form the majority of organisms), Candida species, and nondermatophyte molds.

Objective:

To evaluate the efficacy and safety of itraconazole and terbinafine in the treatment of some nondermatophyte molds that cause toe onychomycosis and to review the literature on the treatment of nondermatophyte mold toe onychomycosis using the oral antifungal agents.

Patients and Methods:

Patients with nondermatophyte mold toe onychomycosis were treated in an open, prospective manner with either itraconazole (pulse) or terbinafine therapy. In each instance, light microscopic examination was consistent with the diagnosis of a nondermatophyte mold. For each patient, mycological evaluation of the target nail resulted in 3 or more successive cultures yielding growth of the mold alone.

Results:

All 15 patients had onychomycosis of the toes which was of the distal and lateral type. The patients were treated with itraconazole given as the standard 3 pulses with additional pulses administered depending upon the response exhibited by the toe onychomycosis in the patient. Similarly, terbinafine was given for 12 weeks with additional therapy administered as dictated by the response. Efficacy parameters were mycological cure (MC) and clinical cure (CC). Mycological cure was negative light microscopic examination (KOH) and culture. Clinical cure was the appearance of a completely normal-looking nail. At month 12 from the start of treatment, the response was as follows: Scopulariopsis brevicaulis: itraconazole (MC 4/4, CC 2/4) and terbinafine (MC 0/1, CC 0/1), Fusarium species: itraconazole (MC 1/1, CC 1/1) and terbinafine (MC 0/1, CC 0/1), Aspergillus species: itraconazole (MC 5/6, CC 3/6), Alternaría alternata: itraconazole (MC 0/1, CC 0/1), and Onychocola canadensis: itraconazole (MC 1/1, CC 0/1). There were no significant clinical or laboratory adverse effects.

Conclusions:

In the present series itraconazole demonstrated efficacy against onychomycosis of the toenails caused by 5. brevicaulis and Aspergillus species. A review of the literature confirms our experience with itraconazole and further suggests that terbinafine may also demonstrate efficacy against cases of S. brevicaulis and Aspergillus toe onychomycosis. Additionally, reports in the literature suggest that pedal onychomycosis caused by Fusarium species may also show response to itraconazole and terbinafine. For the other species, there are fewer data, making it difficult to draw conclusions.

Management of Onychomycosis in Canada in 2014

Background

Onychomycosis has several clinical presentations and is caused by various infectious organisms.

Objective

To provide guidance for selection of appropriate treatment.

Methods

The literature on onychomycosis management was reviewed to generate an evidence-based decision tree.

Results and Conclusion

Several options are available: terbinafine, itraconazole, fluconazole, ciclopirox 8% nail lacquer, efinaconazole 10% nail solution, and laser therapy. Further studies on lasers are needed before use can be recommended. Nondermatophyte molds or mixed infection can be managed with terbinafine or itraconazole with or without topicals. Itraconazole, fluconazole, and efinaconazole can be used for Candida infection. For dermatophytes, topicals can be considered for mild to moderate onychomycosis. For moderate to severe cases, any oral monotherapy can be used; however, we suggest terbinafine if there is a possibility of a drug interaction. These recommendations can be applied for all ages, immune function, or metabolic status, but proper monitoring and contraindications should be taken into consideration.

[Onychomycoses due to molds]

Onychomycoses represent about 30% of superficial mycosis that are encountered in Dermatology consults. Fungi such as dermatophytes, which are mainly found on the feet nails, cause nearly 50% of these onychopathies. Yeasts are predominantly present on hands, whereas non-dermatophytic moulds are very seldom involved in both foot and hand nails infections. According to literature, these moulds are responsible for 2 to 17% of onychomycoses. Nevertheless, we have to differentiate between onychomycoses due to pseudodermatophytes such as Neoscytalidium (ex-Scytalidium) and Onychocola canadensis, which present a high affinity for keratin, and onychomycoses due to filamentous fungi such as Aspergillus, Fusarium, Scopulariopsis, Acremonium... These saprophytic moulds are indeed most of the time considered as colonizers rather than real pathogens agents. Mycology and histopathology laboratories play an important role. They allow to identify the species that is involved in nail infection, but also to confirm parasitism by the fungus in the infected nails. Indeed, before attributing any pathogenic role to non-dermatophytic moulds, it is essential to precisely evaluate their pathogenicity through samples and accurate mycological and/or histological analysis. The treatment of onychomycoses due to non-dermatophytic moulds is difficult, as there is today no consensus. The choice of an antifungal agent will first depend on the species that is involved in the infection, but also on the severity of nail lesions and on the patient himself. In most cases, the onychomycosis will be cured with chemical or mechanical removing of the infected tissues, followed by a local antifungal treatment. In some cases, a systemic therapy will be discussed.

[A case of onychomycosis caused by Aspergillus sydowii]

Onychomyosis caused by Aspergillus sydowii is rare and difficult to diagnose. We report a case in which this disease was diagnosed by molecular-biological methods. The patient was a 53-year-old woman without any notable past history. She visited our hospital complaining of itching around the right first toenail in June 2010, although she had noticed nail opacification for 4 years. Opaque thickening of the nail, covering 57.3% of the normal nail area, was observed. Direct microscopic examination revealed thick mycelia with septa and black spores. While colonies with a red brown center and a grayish blue-green margin were observed in culture on Sabouraud ' s glucose agar at 25℃, radially arranged conidia in the conidial head were observed in slide culture. Thus, onychomycosis caused by Aspergillus was suspected. There were no blood or biochemical test abnormalities. We directly extracted deoxyribonucleic acid from the nail and analyzed the base sequences of the internal transcribed spacer 1 and 2 regions of the ribosomal ribonucleic acid gene, and identified Aspergillus sydowii. Because the minimal inhibitory concentration of itraconazole (ITCZ) is 0.25 μg/ml, we administered pulse therapy with monthly 1-week cycles of oral ITCZ 400 mg / day for 3 consecutive months. The opaque area subsided to 17. 9% of the normal nail by 6 months after treatment completion. However, 3 months later, the opaque area increased again to 22. 3%, and the same fungus was isolated and identified. The 3-month ITCZ pulse therapy was repeated and the symptoms disappeared, with complete cure achieved by 3 months after the second therapy.

Fingernail Onychomycosis Due to Aspergillus niger

Onychomycosis is usually caused by dermatophytes, but some species of nondermatophytic molds and yeasts are also associated with nail invasion. Aspergillus niger is a nondermatophytic mold which exists as an opportunistic filamentous fungus in all environments. Here, we report a case of onychomycosis caused by A. niger in a 66-year-old female. The patient presented with a black discoloration and a milky white base and onycholysis on the proximal portion of the right thumb nail. Direct microscopic examination of scrapings after potassium hydroxide (KOH) preparation revealed dichotomous septate hyphae. Repeated cultures on Sabouraud's dextrose agar (SDA) without cycloheximide produced the same black velvety colonies. No colony growth occurred on SDA with cycloheximide slants. Biseriate phialides covering the entire vesicle with radiate conidial heads were observed on the slide culture. The DNA sequence of the internal transcribed spacer region of the clinical sample was a 100% match to that of A. niger strain ATCC 16888 (GenBank accession number AY373852). A. niger was confirmed by KOH mount, colony identification, light microscopic morphology, and DNA sequence analysis. The patient was treated orally with 250 mg terbinafine daily and topical amorolfine 5% nail lacquer for 3 months. As a result, the patient was completely cured clinically and mycologically.

A case of onychomycosis caused by Aspergillus candidus

Based on epidemiological studies, Aspergillus candidus has been demonstrated as an emerging fungal agent of toenail onychomycosis. Here we report a case of a toenail infection caused by A. candidus in a healthy 60-year-old woman. Based on macroscopic and microscopic characteristics of the culture as well as nucleotide sequencing of 28S region, the causative agent was identified as A. candidus.

Curing onychomycosis: understanding the multitude of variables

This article provides a focused look at the need to treat onychomycosis from a podiatric perspective, new classifications of the disorder, definitive diagnostic methods, predictability of host responsiveness, and current strategies for treatment.

Non-dermatophyte onychomycosis

Non-dermatophyte organisms are becoming increasingly prevalent in onychomycosis. This apparent emergence might be an artifact of improved diagnostic techniques and increased awareness that these fungi are potential etiologic agents. It is important to bear in mind that all isolated organisms should be evaluated as potential pathogens when diagnosing fungal infections, especially given the increasing use of immunosuppressive drugs and the increasing numbers of chronically immunocompromised individuals. While many patients with non-dermatophyte mold onychomycosis will respond to oral or topical antifungal therapy, poor or incomplete response might still be expected in some patients.

A new classification of onychomycosis

This new classification of onychomycosis is a development of previous schemes and depends on the recognition of different clinical patterns of nail plate involvement associated with fungal infection as well as histopathology. The main types are distal and lateral subungual onychomycosis, superficial onychomycosis, proximal subungual onychomycosis, endonyx onychomycosis and total dystrophic onychomycosis. In addition, patients may show different combinations of these patterns. The identification of clinical patterns of disease may be useful in defining differences in clinical behaviour, treatment response and associated disease.