Introduction

Skin illness is one of the many age-related diseases that are becoming more prevalent as life expectancy rises globally. Toenail fungus can be fairly frequent among nail problems, and fungal infection is the third most common ailment observed by clinicians. According to the World Health Organisation, people between the ages of 60-80 are commonly affected by skin disorders. Age, lifestyle, and habits are some of the factors that contribute to nail abnormalities in elderly patients. Other causes include diabetes mellitus, which has an estimated 11% to 14% incidence of onychomycosis. When infection is not properly diagnosed, patients may self-medicate or receive inappropriate treatment for changes in the nail plate's appearance. Combining medications used to treat the nail condition with other medications the patient is taking concurrently for other conditions can lead to therapeutic failure and even serious complications. For instance, itraconazole or fluconazole may interact with oral antidiabetic medications.²

A common occurrence in basic care is onychomycosis, a chronic fungal infection of the fingernail or toenail bed. The issue of onychomycosis is not merely a cosmetic one. If left untreated, it can limit physical function and create pain and suffering, which will lower quality of life. The greatest patient-centred evidence on the diagnosis and treatment of this illness is compiled in this article.

Onychomycosis can actually have a major detrimental impact on a patient's emotional, social, and professional functioning as well as costing a large amount of money in medical care. Patients who are affected may feel ashamed in social and professional settings, feel degraded or dirty, and not want their hands or feet to be seen. The fear that they will spread their infection to friends, family, or coworkers can cause patients to avoid personal interactions and have low self-esteem.

On the other hand, little information is available regarding the age at which older adults' onychomycosis completely resolves. Thus, the purpose of this study was to ascertain for older adults with toenail onychomycosis the age and other parameters linked to a full recovery, together with the pertinent baseline data, such as prescription medication use and medical comorbidities.¹

Causes and risk factors

Although dermatophytosis of the stratum corneum, hair, and nails are frequent, these agents rarely infect the dermis and subcutaneous tissue. Despite being rarely fatal, dermatophytic infections are a significant public health concern due to their high incidence, prevalence, and related morbidity. There are conflicting reports regarding the prevalence of onychomycosis; estimates range from 1 to 4% of the general U.S. population to 14% of Finnish males. Culture-confirmed dermatophyte onychomycosis was found in 9.1% of the overall population and in 7% and 13.3% of the female and male subgroups, respectively, in a recent outpatient-based, cross-sectional survey of 1,038 patients in a Cleveland, Ohio, dermatology clinic waiting room (patients who presented for onychomycosis were excluded). These numbers are similar to the 8.2% for the entire Finnish population. Several studies have indicated that the prevalence of onychomycosis increases with age. For instance, of the 200 Finnish participants under the age of 20, none got onychomycosis, but over 25% of those 70 and older did.² 

In the Ohio cohort, 29% of participants aged 60 years or older had a positive onychomycosis culture, compared to 1.1 and 2.9% for participants aged 11 to 17 and 18 to 30 years, respectively. Age-related increases in onychomycosis can be caused by a number of factors, such as poor peripheral circulation, diabetes, repetitive nail injuries, prolonged exposure to pathogenic fungus, weakened immune systems, inactivity, or the incapacity to maintain proper foot hygiene or trim toenails.⁹

Due to poor peripheral circulation, weakened immune systems, slower nail growth, and prolonged exposure to harmful fungus, age over 60 is a significant risk factor. Recurrent nail trauma, tobacco use, and specific comorbidities (diabetes mellitus, obesity, psoriasis, cancer, HIV, peripheral vascular disease, and immunocompromised status) are additional risk factors. 

Infections with onychomycosis in the US are 70% caused by dermatophytes, with non-dermatophyte moulds and yeasts accounting for the remaining 30%. According to one study, 39% of infections were mixed (caused by non-dermatophyte mould and/or yeast in addition to dermatophytes), which makes diagnosis and treatment difficult.⁴

Symptoms and diagnosis 

The differential diagnosis for nail abnormalities is broad because fungi are responsible for 50% of nail dystrophies. Nails that look discoloured, distorted, hypertrophic, or hyperkeratotic; subungual debris; detachment from the nail bed; brittle nails that crumble or break easily; and foul-smelling nails are all common indications and symptoms of onychomycosis. The Onychomycosis Severity Index classifies severity as mild, moderate, or severe evaluates the severity using three clinical characteristics: the region of involvement, the disease's proximity to the nail matrix, and the existence of dermatophytoma or subungual hyperkeratosis with a thickness of more than 2 mm.⁹

The second kind of Candida onychomycosis, known as Candida granuloma, which makes up less than 1% of onychomycosis cases, is more common in patients with persistent mucocutaneous candidiasis. This disorder, which involves direct invasion of the nail plate, is observed in immunocompromised people. The organism directly invades the nail plate and may impact the entire nail thickness. In more severe cases, this can lead to swelling of the proximal and lateral nail folds until the digit takes on the look of a "chicken drumstick" or pseudo-clubbing.⁶ 

Accurate diagnosis of nail infections requires laboratory confirmation. Direct microscopy combined with a potassium hydroxide (KOH) preparation is the recommended diagnostic technique because of its high specificity, quick turnaround time, and affordability. Starting treatment just requires a diagnosis made using KOH preparation. However, additional testing may be carried out to confirm the diagnosis if KOH tests are negative and there is a high possibility of onychomycosis.³

Although fungus culture of nail clippings or subungual detritus enables species separation, the process is time-consuming and expensive. Periodic acid-Schiff staining of nail clippings and biopsy can be used to determine the extent of nail plate involvement. Although it costs more than other tests, the polymerase chain reaction can also confirm the diagnosis. It might be necessary to cut the nail plate to expose the most proximal area of onycholysis in order to collect samples from this location. Although diagnostic testing is usually advised prior to starting treatment, terbinafine empirical treatment may be an option if testing is too expensive.⁶ 

Treatment options

The following are indications for topical and oral therapy. Prior to starting treatment, shared decision-making should be utilised to determine the severity of the condition, the duration of treatment, the cost, comorbidities, the risk of drug-drug interactions, side effects, and patient choice. Clinical characteristics and the extent of nail involvement determine the kind of treatment. If onychomycosis is not treated, it will worsen and can significantly affect quality of life. 

Oral therapy

The best treatment for onychomycosis, regardless of severity, is oral medication. Compared to topical therapy, oral antifungals offer shorter treatment durations and higher cure rates. Based on its total nail removal and negative microscopy and culture results, terbinafine is the most effective oral medication and ought to be used as first-line treatment. The cost of terbinafine is lower than that of topical medications. Beta-blockers, tamoxifen, tricyclic antidepressants, selective serotonin reuptake inhibitors, and atypical antipsychotics are among the medications that may interact with concurrent terbinafine therapy. Due to its lengthy course of therapy, increased risk of side effects, and poorer cure rates when compared to other drugs, glimeofulvin is rarely used. There were no appreciable variations in the safety or efficacy of continuous versus pulse-dosing oral antifungal regimens for the treatment of toenail onychomycosis, according to a systematic study. Although terbinafine and itraconazole are regarded as off-label medicines, the FDA has not approved any systemic medications for the treatment of onychomycosis in children. Given that toenails can take up to 18 months to fully regrow and fingernails often take three to six months, clinicians should advise patients about reasonable expectations for full recovery.¹⁰ 

Topical therapy

Topical therapy can be used as an alternative first-line treatment for patients with superficial onychomycosis or early distal lateral subungual onychomycosis due to its low risk of side effects and minimal drug-drug interactions, despite being less effective and more costly than oral therapy. For fingernails, topical therapy should last 24 weeks, and for toenails, 48 weeks. Typically, the only side effects are dermatitis, burning, erythema, and exfoliation at the application site. The FDA has approved ciclopirox 8% topical solution for mild to moderate onychomycosis of the fingernails and toenails. One treatment option for mild to moderate onychomycosis is 10% efinaconazole. Mild distal lateral subungual onychomycosis and onychomycosis without matrix involvement can both be treated with Amorolfine 5% lacquer.²

Surgical therapy

To improve the efficacy of treatment, nail debridement and clipping might be combined with topical or oral medication. When medical treatment is ineffective or there is a significant infection, both surgical and nonsurgical nail removal may be recommended. Based on limited RCTs and low-level evidence, the FDA has approved dual-wavelength infrared and fractional carbon dioxide laser therapy for the short-term cosmetic enhancement of nails.⁷

Prevention strategy

Experts believe that avoiding barefoot walking in public areas may help stop recurrence. Patients should keep their feet cool and dry, clean their shoes and socks, and be aware of the early warning symptoms of reinfection and recurrence. Because the affected skin can serve as a reservoir for infections, treating tinea pedis right away can help postpone the recurrence of onychomycosis. It has been demonstrated that twice-weekly topical antifungal prophylaxis after terbinafine treatment lowers the recurrence rate when compared to no prophylaxis. 

Healthy behaviours to avoid reinfection and have the best possible therapeutic response. To help maintain shoes free of germs, apply antifungal powders once a week. Onychomycosis is more likely to develop in people with tinea pedis, thus they may require special education to prevent it. Patients should be counselled to be vigilant for infection recurrence in addition to the aforementioned guidelines.⁴

Support and education for the patient might also be provided by a physician. Every attempt should be made to support patient adherence to the recommended plan and to understand the frustration that patients may experience during lengthy treatment regimens. A calendar with precise dates for laboratory testing, follow-up physician appointments, and medicine "on" days and weeks may be helpful for patients following pulse regimes.⁸

Summary

Onychomycosis is primarily caused by dermatophytes, however there is regional and temporal heterogeneity among the infecting bacteria. Dermatologists and other medical professionals now have access to medications with high cure rates and superior safety profiles after decades of frustration and disappointment with this tenacious virus. Additionally, brief treatment periods boost patient adherence, lower treatment expenses, and give patients optimism that their unpleasant infections will be resolved. Therefore, onychomycosis in older adults should be a worry, particularly for those who are 60-70 years of age or older. Prior research on terbinafine-treated patients with toenail dermatophytosis revealed that the full cure rates at 48 months were 28% for those over 65 and 36.5% for those under 65. Similarly, the current investigation found that the median time to a complete recovery was longer and the cure rate was lower for older persons aged > 70. As a result, patients over 70 years old received oral antifungal medication less frequently and with caution than individuals under 70. According to a different study, thicker nail plates had a detrimental effect on the full cure rate compared to older persons under 70.