Resistance of Candida species to antifungal agents used in the treatment of onychomycosis: a review of current problems

Treatment of Candida infections with fluconazole has resulted in the emergence of drug resistance, a problem particularly apparent in HIV-infected patients. Frequently, the yeast is also cross-resistant to itraconazole and other azoles. In neutropenic patients fluconazole therapy or prophylaxis has caused overgrowth and infection by inherently less susceptible species of Candida, principally C. glabrata and C. krusei. Consequently, the use of intermittent long-term azole therapy to treat onychomycosis could result in changes in the commensal yeast flora of patients--either resistance or pathogen shift. An 'off-study' investigation undertaken in patients receiving either continuous terbinafine or intermittent itraconazole for toenail onychomycosis (L.I.ON. study) showed no evidence of changes in the yeast species present, nor in their sensitivity to itraconazole or fluconazole. Although intermittent itraconazole seems unlikely to cause problems in this respect, the situation with regard to intermittent fluconazole therapy of onychomycosis needs further study.

A health-related quality of life measure for use in patients with onychomycosis: a validation study

Onychomycosis is a common nail disorder associated with pain, discomfort and varying degrees of physical impairment and loss of dexterity. Psychological and social limitations result from reactions of others to visible impairment. The goal of this research is to validate a questionnaire to measure the impact of toenail onychomycosis on health-related quality of life (HRQoL). One hundred and fifty onychomycosis patients were enrolled in an observational study at eight sites in the US. Attending physicians reported information on clinical status at enrolment. Patients completed a questionnaire covering HRQoL that included general and disease-specific items measuring the impact of onychomycosis on activities and appearance, plus problems and symptoms associated with toenail infection. The subscales of the instrument showed high internal consistency reliability (range = 0.63-0.95). Construct validity reflected the close association of physical functioning scores with onychomycosis impairment. Test-Retest reliability was good to excellent for all scales (ICC = 0.52-0.89). Discriminant validity was evidenced by persons who are younger and female reporting worse disease-specific HRQoL. Responsiveness to clinical change was noted for all disease-specific scale scores for improved patients. This instrument has demonstrated reliability, validity and responsiveness for use in observational and clinical studies of toenail onychomycosis patients. Data indicate that onychomycosis patients report significant pain and discomfort reflecting the need for HRQoL measurement.

The safety of itraconazole in the diabetic population

This study examined the safety of itraconazole for the treatment of onychomycosis in patients with diabetes mellitus compared with standard palliative treatment. Fifty-two diabetic subjects in a large Veterans Affairs health system who had been diagnosed as having lower-extremity complications and distal dermatophytic subungual onychomycosis of the toenail were randomized to receive either intermittent itraconazole, 200 mg twice daily, or standard palliative care, consisting of toenail trimming, cleaning, and soaking. Adverse events were reported in 4 of the 27 itraconazole subjects; no adverse events were reported in the 25 palliative treatment subjects. One itraconazole subject was withdrawn from the study because of elevated liver function test results; the other three adverse events (rash, diarrhea, and pedal edema) were considered self-limiting and did not interfere with protocol completion. Analyses of prestudy and poststudy hemoglobin A1c and liver function test results in both treatment groups were comparable, with no statistically significant differences. Itraconazole was found to be safe for the treatment of distal dermatophytic subungual onychomycosis in diabetic patients with lower-extremity complications having multiple concomitant disorders and requiring concurrent pharmacologic regimens.

Acute infection with Trichophyton rubrum associated with flares of atopic dermatitis

Trichophyton rubrum has been implicated as a potential trigger in flares of atopic dermatitis. We describe a patient with atopic dermatitis who presented with a history of multiple flares and concurrent acute tinea pedis and onychomycosis. Symptoms of atopic dermatitis and culture-positive acute infection with T. rubrum resolved during each flare using systemic antifungals. Flares of atopic dermatitis may be triggered by acute T. rubrum infections. Antifungal therapy should be considered in these patients.

[Acute hepatocytic necrosis during ketoconazole therapy for treatment of onychomycosis. National Foundation for Registry and Evaluation of Adverse Effects]

The imidazole derivative ketoconazole is approved in the Netherlands for treatment of local and systemic fungal infections. Despite the risk of major hepatic damage, this antimycotic drug is still being used in daily practice for the oral treatment of patients with onychomycosis. Since April 1986, 18 cases of relatively severe hepatic damage in the Netherlands were ascribed to the oral use of ketoconazole for the treatment of onychomycosis, skin infection or vaginal candidiasis. Given the potential risk for the patients concerned, ketoconazole should no longer be prescribed for relatively mild cosmetic disorders such as onychomycosis.

Prevalence and epidemiology of toenail onychomycosis in diabetic subjects: a multicentre survey

The number of individuals diagnosed with diabetes mellitus is increasing. The diabetic may present with complications involving all systems of the body. While onychomycosis is often observed in diabetics, there have been no large studies on the prevalence of the condition in this patient group. We examined the prevalence of onychomycosis in diabetics attending diabetes and dermatology clinics in London, Ontario, Canada and Boston, MA, U.S.A. Diabetic subjects seen in dermatology offices were for unrelated dermatoses; those referred specifically for the management of onychomycosis were excluded from the sample. A total of 550 diabetic subjects was evaluated (283 males and 267 females), age 56.1 +/- 0.7 years (mean +/- SEM). Patients with type I diabetes constituted 34% of the sample. The racial origin was: 531 Caucasians, 17 Asians, one African-American and one American-Indian. Abnormal-appearing nails and mycological evidence of onychomycosis (mostly due to dermatophytes) were present in 253 (46%) and 144 (26%), respectively, of 550 subjects. The development of onychomycosis was significantly correlated with age (P < 0.0001) and male gender (P < 0.0001). Males were 2.99 times more likely to have onychomycosis compared with females (95% confidence interval, CI 1.94-4 61). After controlling for age and sex, the risk odds ratio for diabetic subjects to have toenail onychomycosis was 2.77 times compared with normal individuals (95% CI 2.15-3.57). After controlling for age and sex, a stepwise logistic regression demonstrated that significant predictors for onychomycosis included a family history of onychomycosis (P = 0.0001), concurrent intake of immunosuppressive therapy (P = 0.035) and peripheral vascular disease (P = 0.023). Toenail onychomycosis was present in 26% of the sample and is projected to affect approximately one-third of subjects with diabetes. Predisposing factors include increasing age, male gender, family history of onychomycosis, concurrent intake of immunosuppressive agents and peripheral vascular disease.

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.

Onychomycosis in HIV-positive patients

Onychomycosis is a common podiatric condition that has become an increasing problem as the number of patients with HIV infection has grown. Although it is not among the most severe infections that affect HIV-positive patients, it tends to be more extensive, refractory to treatment, and has a unique clinical presentation in this patient population. It is important for the podiatric physician to be aware of the epidemiology, clinical presentation, diagnosis, and treatment of onychomycosis in HIV-positive patients.

Candida onychomycosis in HIV infection

Primary nail invasion by Candida is uncommon and almost exclusively seen in patients with an impaired immune function. The appearance of Candida onychomycosis in an adult who is not under immunosuppressive treatment always requires a laboratory evaluation of the immunologic function including HIV assays. We report 2 cases of distal subungual onychomycosis due to Candida sp. in HIV. In one of our patients, the diagnosis of Candida onychomycosis preceded the diagnosis of advanced HIV infection. In both of our patients treatment with systemic antifungals produced complete cure of Candida onychomycosis and the 1 year follow-up did not reveal any relapse of the onychomycosis.

[Tinea follicularis presenting as trichophytic Majocchi granuloma]

We report on a 75 year old patient with a bronchial asthma treated at least for 15 years with low dose prednisolone. Under this treatment he developed a tinea follicularis and was demonstrated in our clinic with papulopustular skin lesions on both forearms, left malleolus and left thigh. We saw tender to touch granulomata on erythematosquamous atrophic skin. A dermatomycosis was diagnosed by isolation and identification of Trichophyton rubrum. In addition the onychomycosis of all finger- and footnails was caused by T. rubrum. Clinical and accessory clinical findings (histology) agreed with a 1883 described disease, granuloma trichophyticum Majocchi. An internal treatment with terbinafine 250 mg/d and topical with tioconazole cream completely cured the skin lesions and the nails.

A unique case of Cryptococcus laurentii keratitis spread by a rigid gas permeable contact lens in a patient with onychomycosis

PURPOSE

We report the first case of fungal keratitis caused by Cryptococcus laurentii, a nonneoformans species.

METHODS

A case of C. laurentii keratitis in a diabetic, gas permeable contact lens wearer was diagnosed after microbiologic evaluation of the corneal button after emergent keratoplasty. The excised cornea was also culture positive for Staphylococcus aureus and Fusarium solani. The medical history was significant for onychomycosis of the right great toe 2 months previously. Cultures of the toenail and of the contact lens case were also positive for C. laurentii and F. solani.

RESULTS

An initial penetrating keratoplasty with histopathologically clear margins was unsuccessful in preventing intraocular spread of the fungal infection. Despite a repeat limbus-to-limbus therapeutic keratoplasty, pars plana vitrectomy, multiple anterior chamber washouts, intravitreal antifungal injections, and systemic antifungal treatment, the eye was ultimately lost due to ongoing inflammation, ocular hypotony, and a total retinal detachment. Histopathologic examination of the enucleated eye demonstrated filamentous fungi but no yeast forms.

CONCLUSIONS

C. laurentii, a nonneoformans species, should be included in the differential diagnosis of fungal keratitis. This unique case also demonstrates the importance of a thorough clinical history and proper contact lens hygiene, particularly in a diabetic patient.

Onychomycosis. Baseline results of an observational study

The investigators present an analysis of baseline quality-of-life and patient-management approaches from an observational study of 150 patients being treated by podiatric physicians and dermatologists for onychomycosis. The majority (73%) made the initial office visit specifically because of their onychomycosis. Both men and women indicated that they had substantial physical discomfort as well as concerns related to appearance. Women reported significantly more problems than did men as a result of their onychomycosis. Physicians reported that 54% of patients suffered from toenail discomfort, 36% had pain while walking, 40% reported that their condition limited wearing of shoes, and 67% were embarrassed by the condition. The results of this study suggest that the treatment approach of podiatric physicians is more likely to address the palliative concerns of patients with onychomycosis, while the approach of dermatologists is more likely to attempt a definitive cure.

A higher prevalence of onychomycosis in psoriatics compared with non-psoriatics: a multicentre study

There is some controversy about the prevalence of onychomycosis in patients with psoriasis compared to non-psoriatics. We therefore measured the prevalence of toenail onychomycosis in psoriatics and non-psoriatics attending dermatologists' offices. None of the patients had a referring diagnosis of onychomycosis. The prevalence of pedal onychomycosis in psoriatics (n = 561) was 13%. The odds of patients with psoriasis having onychomycosis was 56% greater than non-psoriatics of the same age and sex (P = 0.02). In the psoriatics, when the toenails were clinically abnormal, the prevalence of onychomycosis was 27%. The odds of developing onychomycosis increased with age (P < 0.0001) and the odds of men developing onychomycosis was 2.5 times that of women (P = 0.0001). The duration of psoriasis did not significantly affect the odds of developing onychomycosis. The fungal organisms recovered from psoriasis subjects with onychomycosis were similar to those in the normal population with onychomycosis (P = 0.58).

Childhood white superficial onychomycosis caused by Trichophyton rubrum: report of seven cases and review of the literature

BACKGROUND

Although white superficial onychomycosis (WSO) is well recognized in adults and considered to be mainly caused by Trichophyton mentagrophytes, childhood WSO is rare. WSO caused by Trichophyton rubrum in prepubertal children has never been reported.

OBJECTIVE

Our purpose was to describe the existence of WSO in children and to emphasize that T. rubrum may be its main cause.

METHODS

Seven children with WSO seen between 1988 and 1993 were examined. Only patients who had a positive potassium hydroxide preparation and a positive fungal culture were included.

RESULTS

Seven healthy prepubertal children, 2 to 9 years of age, were identified with WSO. All cases were proved to be caused by T. rubrum. Six patients had associated tinea pedis, and five had a family history of tinea pedis. Topical antifungal therapy was partially effective in some cases.

CONCLUSION

This report documents the existence of WSO in prepubertal children. All cultures grew T. rubrum. Although onychomycosis is not as common in prepubertal children as in adults, it may be underrecognized.

Unusual Microsporum canis infections in adult HIV patients

Tinea capitis in men, even if infected with HIV, is infrequent. Microsporum species nail infections are extremely rare. In most cases Microsporum canis infection is usually easy to treat with antifungal agents. We describe two HIV-infected men with an unusual M. canis infection. Both patients had tinea capitis, presenting as alopecia in one and scaling of the scalp in the other. One patient also had tinea unguium caused by M. canis. Ketoconazole was ineffective in both patients; terbinafine was tried in one patient without benefit; itraconazole was effective in both, but treatment took many months and only one patient was cured.

Pathomorphological findings in a case of onychomycosis of a racehorse

The hooves of a racehorse which were affected with white line disease and hoof wall disorders on both forelimbs were histopathologically investigated using thin ground section and standard paraffin section techniques. On both hooves, large quantities of fungus were found to have invaded the white line tissues, especially in the terminal horn which were markedly damaged. The fungus was also present among the cellular debris in the fissures of horny tissues. The morphological characteristics of the fungus were brown (its natural color), PAS-positive, mold-like shape with septa inside the tissues, and unicellular spores outside the tissues. These findings suggest that onychomycosis was a primary and/or secondary cause of white line disease in this subject.