Terbinafine in the treatment of onychomycosis: a review of its efficacy in high-risk populations and in patients with nondermatophyte infections

BACKGROUND

The prevalence of onychomycosis is higher in certain high-risk populations, such as the immunocompromised, diabetics and human immunodeficiency virus (HIV)-positive patients. These patients can also develop onychomycosis due to nondermatophyte fungi. Although the efficacy of terbinafine is well demonstrated in the treatment of conventional dermatophyte nail infection, there are few data on the efficacy of terbinafine in high-risk patient groups or in nondermatophyte fungi, which can be difficult to treat.

OBJECTIVES

To review previously published data regarding the safety and efficacy of terbinafine in special patient populations, such as those with diabetes mellitus or HIV infection, those receiving immunosuppressive therapy, and patients with onychomycosis due to nondermatophyte fungi.

METHODS

A Medline literature search up to October 2002 was performed in order to identify relevant studies. Pertinent abstracts presented at international meetings were also included. Cure rates (per-protocol and intention-to-treat) were extracted or calculated. All available safety data were also collated.

RESULTS

Terbinafine was highly effective and well tolerated in patients with diabetes mellitus. Mycological cure rates of 62-78% were achieved in three studies, which is comparable with the efficacy in nondiabetic populations. Mycological cure rates of 64-91% were achieved in subsets of diabetic patients with Candida-positive nail cultures. The efficacy of terbinafine in patients receiving immunosuppressive therapy was also similar to that reported in immunocompetent patients. Levels of ciclosporin in the blood clearly decreased, with little clinical consequence; however, consideration should be given to the monitoring of ciclosporin levels in patients concomitantly receiving immunosuppressive therapy and terbinafine. Two small studies reported that terbinafine was also effective in treating onychomycosis in HIV-positive patients. Terbinafine was also effective and well tolerated in the treatment of nondermatophyte onychomycosis.

CONCLUSIONS

This review suggests that terbinafine is a safe and effective treatment for onychomycosis in high-risk populations. However, the majority of these studies only included small numbers of patients and larger clinical trials are needed, especially in patients with HIV infection.

Trichophyton rubrum in the external auditory meatus. Fallbericht. Trichophyton rubrum im ausseren Gehorgang

We report the case of a 28-year-old immunocompetent male suffering from otitis externa. The right external auditory meatus was filled with cerumen and detritus, the tympanic membrane covered wallpaper-like with layers of fungi. Mycological analysis revealed Trichophyton rubrum. With further examination tinea pedis of plantar and interdigital type and concomitant onychomycosis of the toenails due to T. rubrum could be detected. The auditory meatus was cleaned and treated topically with clotrimazole. Two weeks later the auditory meatus and the tympanic membrane were bare of fungi and the inflammation was resolved. Treatment of tinea pedis and onychomycosis with terbinafine (systemically and topically) is still lasting.

[Differential diagnosis of onychomycosis]

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.

The prevalence of onychomycosis in patients with psoriasis and other skin diseases

Onychomycosis among psoriasis patients is reported with varying prevalence. This prospective, controlled study investigates the occurrence of onychomycosis among inpatients with psoriasis versus inpatients with other skin diseases. The inclusion period was 15 months. Scrapings from clinically abnormal nails (both fingernails and toenails) were examined using microscopy and culture. The prevalence of onychomycosis in patients with psoriasis was 17/79 = 21.5% compared to 18/142 = 12.7% for patients with other skin diseases (p = 0.13). In 17 mycologically positive psoriasis patients, dermatophytes, yeasts and moulds were isolated in 8, 10 and 4 cases, respectively, and in 18 mycologically positive patients with other skin diseases in 12, 7 and 5, respectively. Onychomycosis occurred more frequently in men than in women (psoriasis patients (p = 0.02), patients with other skin diseases (p = 0.03)). Psoriasis patients had a higher frequency of abnormal nails (82.3%) compared to patients with other skin diseases (37.3%) (p < 0.01) and more severe affection of their toenails than patients with other skin diseases (p < 0.01). It is concluded that the frequency of onychomycosis among inpatients with psoriasis compared to inpatients with other skin diseases is not significantly different.

Dermatophyte test medium culture for evaluating toenail infections in patients with diabetes

OBJECTIVE

To evaluate the performance of the in-office dermatophyte test medium (DTM) culture when used to confirm the diagnosis of onychomycosis in diabetic patients.

RESEARCH DESIGN AND METHODS

Nail samples from 184 diabetic patients who exhibited symptoms consistent with toenail onychomycosis were screened for dermatophyte fungal infection using DTM, potassium hydroxide evaluation, and central mycology laboratory culture tests. The diabetic patient group investigated in this study is a subset of a heterogeneous set of patients who participated in a nationwide survey designed to investigate the use of fungal culture tests by dermatologists, podiatrists, and primary care physicians described in detail elsewhere. The overall sensitivity of the DTM and central laboratory culture methods was estimated and compared. Sensitivity differences between DTM and central laboratory culture methods were tested for statistical significance using the McNemar statistic.

RESULTS

DTM culture was positive in 102 of 184 patients (55%), while the central laboratory culture test detected the existence of fungal infection in 78 of 184 (42%). The two tests were in agreement (both positive or both negative) in 114 of 184 patients (62%). Central laboratory culture identified dermatophytes as the pathogen in 91% of positive cases.

CONCLUSIONS

DTM is a convenient and inexpensive culture test that can be used to confirm dermatophyte infections in diabetic patients with presumed onychomycosis. We found this test to be well suited for use in the primary care setting. Because oral antifungal agents are effective against dermatophyte species, which cause the vast majority of nail infections, diagnosis of onychomycosis requires confirmation of dermatophyte infection only, not identification of genus and species. DTM fulfills this requirement and has a diagnostic yield comparable to central laboratory culture.

Treatment of onychomycosis in the diabetic patient population

Onychomycosis is a common medical condition in patients with diabetes. Conflicting data exist as to whether diabetes predisposes patients to the disease. Controversy notwithstanding, patients with diabetes have several medical conditions (obesity, peripheral neuropathy, and retinopathy) that can inhibit the identification or mask the progression of fungal nail infections. In addition, vascular insufficiency, impaired wound healing, and compromised immunologic status associated with diabetic foot increase the risk of secondary infections in diabetic patients with onychomycosis. Such factors contribute to an increased morbidity and decreased quality of life in these patients and underscore the need for effective antifungal treatment. Oral antifungal agents are generally well tolerated, but serious adverse events independent of or associated with a number of significant drug interactions have been reported. The availability of a topical therapy, ciclopirox topical solution, 8% (Penlac Nail Lacquer), provides clinicians with an additional effective and well-tolerated treatment option. In order to further increase the efficacy of topical or oral treatment, mechanical intervention (e.g., debridement) may be combined with either of these options. Choice of appropriate treatment and careful monitoring of fungal nail infections can prevent significant morbidity in patients with diabetes.

Cutaneous hyalohyphomycosis and onychomycosis caused by Onychocola canadensis: report of the first case from Turkey

We present the first Turkish case of skin and nail infection due to Onychocola canadensis in an otherwise healthy farmer who frequently worked barefoot on soil. Cutaneous involvement consisted of scaly and hyperkeratotic lesions resembling tinea pedis, erythematous plaques, and dermal papulonodules of various sizes simulating Majocchi's granuloma. Repeated cultures from nail plates, skin scrapings and needle aspiration materials from papules or nodules all yielded the same mold on Sabouroud dextrose media with and without cycloheximide, trichophyton agar, and potato dextrose agar at 26 degrees C. The causal isolate was identified as Onychocola canadensis Sigler gen. et sp. nov., a slow-growing arthroconidial hyphomycete, on the basis of its colonial and microscopic morphology. While skin lesions were responsive to daily itraconazole in a dose of 200 mg for three months, the onychomycosis was resistant to therapy. To our knowledge, this is the first presentation of O. canadensis as the cause of cutaneous hyalohyphomycosis to date.

Nail involvement in pemphigus vulgaris

BACKGROUND

Involvement of the nail unit in pemphigus vulgaris (PV) is thought to be rare.

OBJECTIVES

To determine the frequency of nail changes among patients with PV.

METHODS

Nail changes were recorded in patients with PV and were analysed retrospectively. Biopsies were taken from the nail bed and nail matrix for histological and immunofluorescence observations. Microscopic (potassium hydroxide) examination and fungal culture were performed.

RESULTS

Nail changes were present in 30 of 64 (47%) patients with PV. Sixteen patients had onychomycosis and 14 had nail changes due to PV. These included onychomadesis, discoloration, deformity, onychorrhexis, onycholysis, subungual haemorrhage, subungual hyperkeratosis and paronychia. Onychomycosis affected fingernails and toenails, but changes due to PV occurred only in fingernails, most commonly on the thumb and index finger. No connection was found between the patient's occupation and nail involvement, and there was no correlation with the severity or duration of PV. In a control group of 64 patients of similar sex and age, only two had non-specific fingernail changes.

CONCLUSIONS

Nail changes in PV may be more frequent than previously thought.

Autoimmune polyglandular syndrome (APS) type 1 and candida onychomycosis

A 21-year-old female presented at age 2 years with a chronic mucocutaneous candidiasis and at age 3 alopecia totalis. Later, chronic hypoparathyroidism and autoimmune adrenal insufficiency appeared. In addition, malabsorption syndrome and signs of pernicious anaemia occurred. The onychomycosis totally improved under systemic treatment with fluconazole (Diflucan), endocrine and organ failure with replacement therapy. The autoimmune polyglandular syndrome (APS 1) is a rare autosomal recessive inherited disease. Chronic mucocutaneous candidiasis (CMC) generally presents very early in life and is the most frequent of the three main diseases of APS type 1 (chronic hypoparathyroidism, autoimmune Addison's disease). It can be considered as a precocious marker of APS type 1. Consequently, all patients affected by isolated CMC, especially children, should be evaluated and carefully followed up by immunological, biochemical, and clinical tests to recognize signs and symptoms of imminent or ongoing endocrine glandular failure.

Proximal white subungual onychomycosis caused by Microsporum canis in systemic lupus erythematosus

We report the case of a Mexican lupus patient who developed proximal white subungual onychomycosis on multiple toenails. Microsporum canis was the causative agent. Both nail invasion by M. canis and proximal white subungual onychomycosis are rare conditions indicative of an underlying immunodeficiency.

Terbinafine (Lamisil) treatment of toenail onychomycosis in patients with insulin-dependent and non-insulin-dependent diabetes mellitus: a multicentre trial

BACKGROUND

Diabetes mellitus (DM) affects an estimated 175 million people world-wide. Approximately one-third of patients with DM have toenail onychomycosis.

OBJECTIVES

To determine the efficacy and safety of terbinafine treatment of toenail onychomycosis in patients with DM receiving insulin and/or oral antidiabetic agents. Special interest was focused on potential drug interactions with oral hypoglycaemic substances.

METHODS

In a multicentre trial, patients suffering from insulin-dependent DM (IDDM) or non- insulin-dependent DM (NIDDM) with toenail onychomycosis were treated for 12 weeks with oral terbinafine 250 mg daily and followed up to 48 weeks. In addition to clinical, mycological and laboratory investigations, blood glucose levels were monitored.

RESULTS

At the end of the trial (week 48), a mycological cure rate of 73% was achieved. The rates of clinical cure and complete cure (mycological cure plus clinical cure) were 57% and 48%, respectively. There was no statistically significant difference between the NIDDM and IDDM groups with respect to the cure rates (P > 0.05). No hypoglycaemic episode was reported and none of the patients had hypoglycaemia during the treatment phase.

CONCLUSIONS

With excellent cure rates and a good tolerability profile, terbinafine should continue to be a drug of choice for the treatment of toenail onychomycosis in the rising number of NIDDM patients receiving multiple medication.

A multicenter, open-label study of the efficacy and safety of ciclopirox nail lacquer solution 8% for the treatment of onychomycosis in patients with diabetes

This multicenter, open-label, uncontrolled, noncomparative, observational, postmarketing study assessed the efficacy and safety of ciclopirox nail lacquer solution 8% in 3666 patients for the treatment of onychomycosis. Results of an analysis in a subset of 215 (5.9%) patients with diabetes are summarized here. Patients applied ciclopirox nail lacquer once daily to affected toenails and fingernails for 6 months. Efficacy parameters included the decrease from baseline of the affected area of the nail. Physicians rated the level of onychomycosis at 3 months and the efficacy of ciclopirox nail lacquer at 6 months. Treatment with ciclopirox nail lacquer reduced the mean affected nail area from 64.3% at baseline to 41.2% at 3 months and 25.7% at 6 months. At 3 months, physicians rated onychomycosis as improved in 88.7% of patients. unchanged in 9.8%, and worse in 1.5%. The efficacy of ciclopirox nail lacquer was good in 62.0% of patients, satisfactory in 23.9%, and unsatisfactory in 14.1%. Adverse events were mild to moderate, with no serious events reported. Ciclopirox nail lacquer is safe and effective for the topical treatment of onychomycosis in patients with diabetes and produced results similar to those observed in the general population.

Prevalence of dermatophytic skin and nail infections in diabetic patients

To determine whether there is a higher frequency of mycotic infections due to dermatophytes in diabetics, 171 diabetic outpatients and 276 controls were recruited in the period 1997-98. Patients with suspicious lesions underwent mycological examination which was positive in seven diabetics and 17 controls. In diabetics the most frequent infection was tinea pedis, followed by distal subungual onychomycosis; the most frequently isolated fungus was Trichophyton mentagrophytes. The results of the study did not show a prevalence of dermatophyte infections in diabetics. No correlation was found between dermatophytosis and duration or type of diabetes and its complications, blood sugar levels or levels of glycosylated haemoglobin. None of the diabetic patients with dermatophytosis had complications related to diabetes and basal blood sugar and glycosylated haemoglobin levels indicated good metabolic control.

[Epidemiologic characteristics of onychomycosis--results of a retrospective study]

INTRODUCTION

The term onychomycosis is used for fungal infections of the nail unit. Tinea unguium is defined as a dermatophyte nail infection. The aim of this study was to determine the epidemiological characteristics of onychomycoses.

MATERIAL AND METHODS

Ambulatory patients of the policlinic department of the Clinic of Dermatovenereology in Novi Sad were included in this study. Every patient with clinically suspected nail changes was examined. Direct microscopy of nail clippings and isolation of fungi on Sabouraud agar were performed. The results were evaluated using standard statistic methods.

RESULTS

During a one-year-period (1995-1996) 70 cases of onychomycoses were registered that is 1.07% of the total number of patients examined in this period (N = 6535). The vast majority of observed patients were females (N = 47-67.14%), and male patients were significantly less frequent (N = 23-32.86%, p < 0.01). The most frequent type was dermatophyte onychomycosis (N = 39-55.71%), and the most often isolated agent was Trichophyton mentagrophytes (N = 38-54.29%). Manual workers were most often affected (N = 18-25.71%). Most patients were in the 41-50 year age group (N = 23-32.86%). The mean age of patients was X = 47.64 years (SD = 15.39). Table 4 shows the clinical duration of different types of onychomycoses. The longest clinical course was in the group of dermatophyte onychomycosis (20 years, one case). The mean clinical duration of the whole group was 26.81 months (SD = 40.04). Table 5 shows presence of other dermatomycoses associated with onychomycoses. Tinea pedis was the most frequently observed dermatomycosis (N = 9-60.00%).

DISCUSSION

The incidence (1.07%) is something less than usual, and other findings are compatible with standard results. A lower incidence could be the result of the fact that children under 17 years are managed at the Institute of Mother and Child Health Care in Novi Sad.

CONCLUSION

This study is a contribution to epidemiological investigations of onychomycoses. This disorder, with its social and medical importance and dubious treatment results, puts onychomycoses on high level of interest in modern dermatovenereology.

Relapses of onychomycosis after successful treatment with systemic antifungals: a three-year follow-up

BACKGROUND

Data about relapses of onychomycosis after treatment with the new systemic antifungals vary among the different studies, with figures ranging from 3 to 20% for terbinafine and from 21 to 27% for itraconazole, depending on the follow-up duration.

OBJECTIVE

To determine the prevalence of relapses of onychomycosis cured by terbinafine compared with that of onychomycosis cured by itraconazole.

METHODS

We followed up 47 patients whose toenail onychomycosis had been mycologically cured in an open randomized study comparing intermittent itraconazole treatment with continuous terbinafine treatment and intermittent terbinafine therapy. Patients were examined every 3 months for up to 3 years after the end of therapy. At each visit clinical and mycologic (direct microscopy and cultures) evaluations were performed.

RESULTS

Eight of the 36 patients (22.2%) who completed the study had a relapse of onychomycosis during the follow-up period, including 2 patients of the terbinafine 250 mg group, 2 patients of the terbinafine 500 mg group and 4 patients in the itraconazole 400 mg group. As the original infection, the relapse was caused in all cases by Trichophyton rubrum.

CONCLUSIONS

This study shows that 22.2% of patients with onychomycosis successfully treated with systemic antifungals experienced a relapse. The relapse rate increased from 8. 3% at month 12 to 19.4% at month 24 and to 22.2% at month 36. Relapses were more common in patients treated with pulse itraconazole (4/11) than in patients treated with continuous (2/12) or intermittent (2/13) terbinafine. Statistical analysis did not reveal any significant difference between relapse rates in the three groups.

The prevalence and management of onychomycosis in diabetic patients

The incidence of diabetes mellitus is increasing throughout the world. Diabetic patients must cope with the serious complications of this condition, such as renal disease, retinopathy and the diabetic foot. To date, very few studies have examined the prevalence of onychomycosis among diabetic subjects. However, two recent studies highlight an increased incidence of onychomycosis and other superficial fungal infections in these patients. Nail and other fungal skin infections pose a greater risk in this patient population because of the possible sequelae. In addition, impaired sensation in the lower extremities can mask minor abrasions and ulcerations on a diabetic patient's foot, which may develop into serious bacterial infections and contribute to the severity of the diabetic foot. Given the potential morbidity that may result from fungal infections of the extremities, effective treatment is of paramount importance. An ideal antifungal agent should combine a broad spectrum of activity with good efficacy and a favorable safety profile.

Onychomycosis: predisposed populations and some predictors of suboptimal response to oral antifungal agents

The population groups predisposed to onychomycosis and factors associated with a poor response to antifungal therapy may be subdivided into (a) genetic, (b) environmental, (c) systemic conditions, (d) local nail characteristics, and (e) other miscellaneous items. By paying attention to the scenarios that may lead to a suboptimal response to the therapy and a higher probability of relapse of the onychomycosis, it may be possible to improve the overall cost-effectiveness of treatments for onychomycosis. Besides attempting to achieve a cure when treating onychomycosis it is important to take steps to prevent reinfection with fungal organisms.