Episode Details

Episode 62: Onychomycosis (nail fungus). 

Future doctors Gabrielle and Jeanette discuss with Dr Arreaza the diagnosis and treatment of onychomycosis, AKA nail fungus.

By Gabrielle Robinson, MS3, and Jeanette Adereti, MS3
Ross University School of Medicine
Facilitated by Hector Arreaza, MD

This is Rio Bravo qWeek, your weekly dose of knowledge brought to you by the Rio Bravo Family Medicine Residency Program from Bakersfield, California. Our program is affiliated with UCLA, and it’s sponsored by Clinica Sierra Vista, Let Us Be Your Healthcare Home.

What is onychomycosis?

-Onychomycosis is a fungal infection that resides in the finger and toenails. The nails become discolored, have onycholysis (painless separation of nail bed), splitting of nail bed, thickened. There are various causes of onychomycosis and examples include the following: dermatophytes, yeast, non-dermatophyte molds.

-Onychomycosis occurs in 10% of the general population.

Microbiology:

Dermatophytes such as Tinea rubrum, account for most onychomycosis infections (~60-70%) while candida account for most of yeast causes of onychomycosis. Non-dermatophyte molds include fusarium, aspergillus, acremonium, scytalidium, Scopulariopsis brevicaulis.

The type of organism involved has an association for the type of infection it causes. Yeast infects fingernails preferentially while the dermatophytes prefer to infect toenails.

Diagnostic testing including culture, KOH preparation and PAS staining can help with confirming fungal infection, but culture not required for empiric treatment with oral terbinafine.

Severity of onychomycosis:

-Mild-moderate: ≤50 percent involvement of the nail and sparing the matrix/lunula

-Moderate-severe: involving >50 percent of the nail or involving the matrix or lunula, including further spread throughout nail.

-It’s common to have multiple nails affected at the same time. Toenails and fingernails can both be affected. Remember to check all nails in your patients. Nails can show signs of local but also systemic diseases.

Risk factors:

-Health conditions: Diabetes, immune suppression, venous insufficiency, peripheral artery disease, or even just having slow growth of the nails. This makes sense because there is decreased blood flow to those areas resulting in decreased immune surveillance of that area. Patient s with PAD are at risk for onychomycosis. Nails normally grow slower in male. Hormones play a role in that growth.

-Exposure: smoking, trauma to the nail, sports, wearing sweaty shoes, being barefoot in communal areas such as swimming pools, college showers, jail house showers, and gyms.

-Dermatological diseases: tinea pedis (athletes’ foot), excessively sweaty hands (hyperhidrosis), psoriasis

-Other factors: old age, having family members whom the patient shares a living space with, bunion (hallux valgus).

Effects on mental health

Unfortunately, the infection takes a toll on the patient because the infection is unsightly it results in psychosocial disturbances. The patients may not want to wear sandals, get pedicures, or shower during gym class if they are school age. These types of feelings can cause patients to not want to go to work or do things they enjoy due to feelings of embarrassment.

Management
Treatment of dermatophyte onychomycosis is guided by causative organism, severity, treatment availability, and cost.

Oral agents
-Oral treatment is generally the gold-standard for onychomycosis due to shorter course and greater efficacy compared to topical. 
-Oral terbinafine is the preferred oral agent. Itraconazole can be used in patients not able to tolerate/respond to terbinafi