Almirall
Dermatology

Onychomycosis

Onychomycosis is the most common nail infective disorder, and it is responsible for about 50% of all consultations for nail disorders. Onychomycosis has been reported as a gender- and age-related disease, being more prevalent in males and increasing with age in both genders. In the elderly, onychomycosis may have an incidence >40%. Predisposing factors are diabetes mellitus, peripheral arterial disease, and immunosuppression due to HIV or immunosuppressive agents.

Onychomycosis is more likely to occur in toenails. The fungus that causes onychomycosis may be of several types, including yeasts, dermatophytes or moulds. In almost all the cases, onychomycosis is caused by dermatophytes, which affect not only the nails but also the skin and the hair, that are tissues containing keratin.

Onychomycosis is characterized by the appearance of white, yellow or black spots at the edge or at the base of the nail, near the cuticle. As the disease progresses, spots spread and cover the whole surface of the nail. The infection colonizes the nail, causing detachment, softening, and deformation. Being an infectious disease, it is therefore contagious and can spread both to the rest of the nails of the same person and to other people through surfaces contaminated with fungi or fungal spores. 

Types of onychomycosis

Based on the parts of the nail affected by onychomycosis, it may be classified in different types. The nail fungus may infect only its surface, the matrix, which affects nail growth, the nail plate or else spread to the nail bed (the part of the finger or toe covered by the nail). Currently, onychomycoses are classified into five different types:

  • Distal and lateral subungual onychomycosis
  • White or black superficial onychomycosis
  • "Endonix" onychomycosis
  • Proximal subungual onychomycosis
  • Total dystrophic onychomycosis 

Diagnosing a specific type of onychomycosis can be complicated due to the wide variability of causing pathogens. Furthermore, in the presence of a potential case of onychomycosis, it is important to rule out other skin conditions that may similarly affect skin and nails, like, for instance, psoriasis, nail trauma or other infections caused by bacteria. 

What causes onychomycosis?

In over 90% of cases, the pathogens that cause onychomycosis are three kinds of dermatophyte fungi—Trichophyton, Epidermophyton, and Microsporum. In the remaining 10%, the causes are yeasts of the genus Candida spp. or other opportunistic fungi (moulds). 

Discover Onychomycosis triggering factors

How is onychomycosis diagnosed?

Your doctor will examine your nails. He or she may also take some nail clippings or scrape debris from under your nail and send the sample to a lab to identify the type of fungus causing the infection.

Other conditions, such as psoriasis, can mimic a fungal infection of the nail. Microorganisms such as yeast and bacteria also can infect nails. Knowing the cause of your infection helps determine the best course of treatment. 

Find more about Onychomycosis diagnosis

How to identify onychomycosis?

Onychomycosis manifests through several distinct physical changes in the appearance and texture of the nail. You will typically notice the nail losing its natural lustre and turning white, yellow, or brown. As the infection progresses, the nail plate often thickens and becomes brittle or crumbly, eventually distorting its shape or even causing it to lift away from the nail bed. In more advanced cases, debris builds up under the nail, leading to a dark, ragged appearance and a foul odour. While many people experience no physical pain initially, the thickened nail can eventually cause significant discomfort when walking or wearing shoes, and the surrounding skin may become red, itchy, or inflamed. 

Curing fingernail and toenail fungus

In general, the initial treatment for diagnosed onychomycosis consists of topical antifungal therapy. Treatments are usually prolonged because they are not easy-to-treat infections. If symptoms persist or get worse, your doctor may prescribe systemic treatments, which are effective but must be monitored to prevent possible adverse effects. Regardless of the type of treatment chosen, it is important to follow the treatment properly because onychomycosis is a disease with a high probability of recurrence both in finger and toenails. 

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