What causes fungal nail infection

Overview

Fungal nail infections, medically termed onychomycosis, are common conditions that affect a significant portion of the population, particularly as people age. These infections occur when fungi invade the nail plate, the nail bed, or the structures beneath the nail. While often not a serious health threat, they can cause discomfort, pain, and cosmetic concerns, leading individuals to seek effective treatments and preventative measures.

What Are Fungal Nail Infections?

Fungal nail infections are caused by various types of fungi, microscopic organisms that are naturally present on our skin, in the environment, and on objects we touch. These fungi feed on keratin, a protein that makes up the nail structure. When the fungi find a favorable environment, they can multiply and infect the nail, leading to changes in its appearance and integrity.

The Main Culprits: Types of Fungi

The fungi responsible for nail infections can be broadly categorized into three main groups:

Dermatophytes

Dermatophytes are the most frequent cause of fungal nail infections, responsible for approximately 90% of all cases. These fungi specifically target keratin. Common dermatophytes include species like *Trichophyton rubrum*, *Trichophyton mentagrophytes*, and *Epidermophyton floccosum*. They thrive in warm, moist conditions and can easily spread through direct contact or contaminated surfaces.

Yeasts

Yeasts, particularly species of *Candida*, are the second most common cause, accounting for about 8% of fungal nail infections. *Candida* is a type of yeast that normally lives on the skin and mucous membranes but can overgrow and cause infection, especially in fingernails, often associated with prolonged exposure to water or in individuals with weakened immune systems.

Non-Dermatophyte Molds

Non-dermatophyte molds are less common culprits, causing around 2% of fungal nail infections. Examples include species like *Aspergillus* and *Scopulariopsis*. These molds are found in the environment, such as soil and decaying vegetation, and typically infect nails that have already been damaged or compromised.

How Do Fungi Infect Nails?

Fungal nail infections usually begin when fungi enter the nail through microscopic cuts, cracks, or separations between the nail and the nail bed. This entry point can occur due to minor trauma to the nail, such as stubbing a toe, improper nail trimming, or wearing tight shoes that put pressure on the toes. Once inside, the fungi begin to feed on the keratin, gradually spreading and causing the characteristic symptoms.

Risk Factors for Fungal Nail Infections

Several factors can increase an individual's susceptibility to developing fungal nail infections:

• Age: Older adults are more prone to infections due to slower nail growth and potentially reduced circulation.
• Trauma to the Nail: Even minor injuries can create an entry point for fungi.
• Moist Environments: Frequent exposure to damp areas like swimming pools, gyms, locker rooms, and humid climates provides an ideal breeding ground for fungi.
• Wearing Occlusive Footwear: Shoes that don't allow the feet to breathe can create a warm, moist environment.
• Weakened Immune System: Conditions like HIV/AIDS, diabetes, or the use of immunosuppressant medications can make individuals more vulnerable.
• Poor Circulation: Conditions affecting blood flow, such as peripheral artery disease, can impair the body's ability to fight off infection.
• Skin Conditions: Conditions like athlete's foot (tinea pedis), which is also a fungal infection, can spread to the nails.
• History of Fungal Infections: Previous infections increase the likelihood of recurrence.

Symptoms of Fungal Nail Infection

Symptoms vary but commonly include:

• Thickening of the nail.
• Discoloration (white, yellow, brown, or black).
• Brittleness, crumbling, or ragged edges.
• Distortion in nail shape.
• Separation of the nail from the nail bed (onycholysis).
• Slightly foul odor.

It is important to note that other conditions, such as psoriasis or bacterial infections, can mimic the symptoms of fungal nail infections, making a proper diagnosis by a healthcare professional crucial.