All You Need to Know About Onychomycosis

Causes and treatments of nail fungus. The most common nail disease.

What is onychomycosis?

What is 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 being more likely to occur in toenails. The fungus that causes onychomycosis may be of several types, including yeasts, dermatophytes or molds. 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 its 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 seven different types: Distal and lateral subungual onychomycosis, White or black superficial onychomycosis, "Endonix" onychomycosis, Proximal subungual onychomycosis, Mixed pattern of onychomycosis, Total dystrophic onychomycosis, and Secondary 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 diseases 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 (molds).

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.

How to prevent onychomycosis?

The following habits can help prevent nail fungus or reinfections:

  • Wash your hands and feet regularly. Wash your hands after touching an infected nail. Moisturize your nails after washing.
  • Trim nails straight across, smooth the edges with a file and file down thickened areas. Disinfect your nail clippers after each use.
  • Wear sweat-absorbing socks or change your socks throughout the day.
  • Choose shoes made of materials that breathe.
  • Discard old shoes or treat them with disinfectants or antifungal powders.
  • Wear footwear in pool areas and locker rooms.
  • Choose a nail salon that uses sterilized manicure tools for each customer.
  • Give up nail polish and artificial nails.

Curing fingernail and toenail fungus

In general, the initial treatment for a 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, you can also use systemic treatments, which are usually more aggressive and, although effective in the short term, they usually have some undesirable side 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.

References

1. Piraccini, B.M, Alessandrini, A. Onychomycosis: A Review. J Fungi [Internet]. 2015 Jun;1(1): 30-43. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5770011/. doi: 10.3390/jof1010030.

2. Mayo Clinic. Nail fungus [Internet]. 2019 Jan 3. Available at: https://www.mayoclinic.org/diseases-conditions/nail-fungus/diagnosis-treatment/drc-20353300

3. Elewski, B.E, Rich, P., Tosti, A., Pariser, D.M, Scher, R., Daniel, R.C, Gupta, A.K. Onchomycosis: An Overview. JDD [Internet]. 2013 Jul;12(7). Available at: https://www.researchgate.net/publication/251878448_Onchomycosis_an_overview