Nail Fungus: Information & Doctors Specializing in Nail Fungus

Nail fungus, also known as onychomycosis or tinea unguium, is a contagious fungal infection.

It is caused by

• dermatophytes (filamentous fungi)
• yeasts,
• molds, or
• a combination of several types of fungi

.

The fungal infection can affect various parts of the nail and manifests as deformation and discoloration of the fingernails or toenails.

Nail fungus is widespread in Germany and Western industrialized countries. It is one of the most common conditions affecting fingernails or toenails. According to estimates, about 12 percent of the population suffers from a nail fungus infection at least once in their lifetime.

Toenail fungus occurs about four times more frequently than fingernail fungus. The cause is often an untreated athlete’s foot infection that has spread to the nails.

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Nail fungus is caused by parasitic fungal pathogens that spread in the nail bed or under the nail.

On the one hand, the development of toenail fungus is caused by infection with these fungal pathogens. On the other hand, certain conditions must be met for them to thrive. Certain risk factors therefore contribute to the development of toenail fungus.

Nail fungus is transmitted through what is known as a smear or contact infection from person to person. A smear infection occurs through direct contact between people. In a contact infection, the patient becomes infected through skin contact with contaminated objects and surfaces.

Nail fungus spores thrive in warm, humid environments, where they multiply particularly rapidly. For this reason, the risk of infection is especially high in such places. These include public wet areas such as swimming pools and saunas, where many people walk barefoot.

Basically, three types of disease-causing fungal pathogens can cause nail fungus:

• dermatophytes,
• yeasts, or
• molds.

In most cases, dermatophytes are responsible for nail fungus infections.

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What pathogens cause nail fungus?

Dermatophytes are also known as filamentous fungi. They almost exclusively infect keratinized areas of the body, such as the skin and its appendages, and feed on keratin. Keratin is the horny substance found in skin, hair, and nails.

In 90 percent of all cases, nail fungus is caused by dermatophytes of the genus Trichophyton rubrum (filamentous fungi). Other possible, but less common, causative fungal pathogens include dermatophytes of the genera Epidermophyton floccosum or Trichophyton mentagrophytes.

In about 3 to 5 percent of cases, dermatophytes of the genus Epidermophyton floccosum are the cause of nail fungus. These dermatophytes primarily affect the skin and subsequently infect the nails. The fungal infection begins at the cuticle and spreads toward the tip of the nail.

Yeast fungi multiply by budding or fission and are therefore also called budding fungi. A nail fungus infection caused by yeast fungi is usually attributable to yeast fungi of the Candida genus. This form occurs particularly in cases of fungal infection of the fingernails.

Signs of this include thickening and discoloration of the nails.

Molds rarely cause nail fungus. Molds that can cause a nail fungus infection include, among others, Scopulariopsis brevicaulis and Aspergillus spp.

What risk factors contribute to the development of nail fungus?

The body’s immune system normally prevents the pathogens that cause nail fungus from multiplying. If the immune system is weakened, pathogens have an easier time.

People with weakened immune systems are therefore particularly susceptible to nail fungus. The immune system can be weakened by

• age,
• underlying medical conditions such as diabetes or HIV,
• surgery, transplantation, or chemotherapy, or
• immunosuppressive medications.

The condition of the nails and the immune system progressively deteriorates over the course of a person’s life. This makes it easier for pathogens to infect the nail tissue. As a result, the risk of a fungal nail infection increases with age. People aged 65 and older are most commonly affected. Nearly one in two seniors suffers from nail fungus.

Atherosclerosis, commonly known as hardening of the arteries, is also a risk factor for nail fungus. Poor blood circulation leads to dry and cracked skin, drastically increasing the risk of infection.

People with diabetes have a weakened immune system, poor blood circulation, and are prone to sensory disturbances.

Athletes face an increased risk of developing nail fungus. For one thing, athletes often have direct contact with people who may have nail fungus. In shared showers and locker rooms, the warm, humid environment can lead to an increased incidence of fungal infections.

Additionally, wearing athletic shoes creates conditions conducive to fungal growth. Sweating inside shoes causes the skin on the feet to soften. In non-breathable athletic shoes, fungi can easily multiply and penetrate the skin, which is poorly protected against moisture.

Athletes such as

• runners,
• tennis players, and
• soccer players

are particularly at risk of contracting nail fungus.

Nail fungus manifests as thickening, deformation, and discoloration of the affected nail © Serhad | AdobeStock

A nail fungus infection can

• the nail root,
• the nail bed, or
• the nail itself

. In most cases, the infection starts at the front edge of the nail and spreads from there across the entire nail plate.

Typical symptoms of a nail fungus infection include

• deformities of the nail,
• brittle and flaking nail layers,
• yellowish-brown discoloration,
• thickening of the nail plate, and
• inflammation of the nail bed.

In cases of severe fungal infection, the infected nail may also emit an unpleasant odor. If the nail fungus is left untreated, there is a very high risk of it spreading to surrounding toenails or fingernails.

If you experience the symptoms described, you should see a doctor immediately. A fungal nail infection does not go away on its own and should therefore always be treated.

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If left untreated, a fungal nail infection can spread to other nails and pave the way for other conditions. The tiny injuries and damage to the nails make it easier for bacteria or viruses to penetrate and cause serious inflammation.

Furthermore, untreated nail fungus can lead to the nail detaching (onycholysis) and destruction of the nail bed.

Symptom Categorization by Pathogen

The symptoms depend on the exact type of nail fungus. Nail fungus can be distinguished based on characteristic symptoms and its location into

1. Distolateral subungual onychomycosis
2. Proximal subungual onychomycosis
3. Leukonychia trichophytica
4. Dystrophic onychomycosis
5. Onychia and Paronychia candidosa

1. Distolateral subungual onychomycosis

Distolateral subungual onychomycosis begins at the anterior edge of the nail. It is by far the most common form of nail fungus. This form of onychomycosis accounts for 90 percent of all nail fungus infections. It usually occurs on the toenails and only rarely on the fingernails.

In this form, the fungal pathogens penetrate through the so-called hyponychium—that is, the germinative layer of skin beneath the nail plate. From there, they slowly spread toward the nail root (nail matrix).

As this happens, the nail plate gradually lifts and turns yellowish.

2. Proximal subungual onychomycosis

This rarer form of nail fungus accounts for about 3 to 5 percent of all nail fungus infections. The infection enters through the skin of the nail fold, i.e., where the nail grows out.

The fungal pathogens penetrate the nail plate from the nail root and slowly spread from there toward the tip of the nail.

3. Leukonychia trichophytica

This form of nail fungus is also known as whitish superficial onychomycosis. It is usually the result of an infection with Trichophyton interdigitale. The nail fungus pathogens spread only in the upper layers of the nail keratin, leading to a whitish discoloration of the affected nail.

4. Dystrophic Onychomycosis

In dystrophic onychomycosis, the structure and function of the nail are significantly impaired and severely altered.

Dystrophic onychomycosis can be the final stage of a long-standing nail fungus infection. However, it can also develop as a result of chronic mucocutaneous candidiasis. This condition is associated with a congenital immunodeficiency.

5. Onychia and Paronychia Candidosa

This form of nail fungus, also known as yeast onychomycosis, is almost always caused by yeasts of the Candida genus. Candida albicans is the most common causative agent.

Typical symptoms include

• chronic inflammation of the nail fold,
• an irregular structure of the nail plate, and
• greenish-brown discoloration of the nail.

Categorization of Symptoms by Stage

A nail fungus infection can be classified into three symptom stages:

Early-stage nail fungus

In the first phase of the infection, those affected notice hardly any symptoms. The nails show the first yellow spots or white streaks. The color changes in the nail are often mistakenly interpreted as a calcium deficiency.

Moderate-stage nail fungus

The toenails or foot nails affected by nail fungus turn yellow, become increasingly thick, and become deformed. The nail begins to separate from the nail bed.

Severe-stage nail fungus

At this stage, the nail may separate completely from the nail bed. This allows bacteria to enter the unprotected skin unimpeded.

In many cases, those affected suffer from additional nail bed inflammation at this stage. The nail is severely curved and emits an unpleasant odor.

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In most cases, a primary care physician or dermatologist can recognize a nail fungus infection at first glance.

To confirm the diagnosis and identify the specific type of fungus, the doctor takes a few samples of the nail’s keratin from the affected nail.

Before taking the sample, the nail is cleaned with 70 percent alcohol and trimmed back as far as possible. Live fungi are found primarily at the border between the healthy nail plate and the infected areas of the nail.

The best way to obtain a nail sample is with a nail drill, as this allows for the collection of a large number of small nail particles. Any local treatment with antifungal medications that may have already begun should have been discontinued 2 to 4 weeks prior to sample collection. Otherwise, false-negative results may occur.

The doctor then places the nail sample obtained in this way on a microscope slide to examine it under a microscope at 10x to 40x magnification. If fungal hyphae or spores are visible during this microscopic examination, the diagnosis of nail fungus is confirmed.

However, it is usually not possible to determine the exact fungal pathogen under the microscope. For this reason, a fungal culture is often performed in the next step to precisely identify the causative agent of the nail fungus.

In this process, the nail fungus pathogen is cultured in the laboratory on a suitable nutrient medium at room temperature for about three to four weeks. Based on the fungal colonies that grow in the culture, it is then possible to determine which specific fungal species is responsible for the nail fungus.

A differential diagnosis is also necessary for a definitive diagnosis of nail fungus. This allows the physician to rule out other conditions as the cause of the nail changes. Symptoms similar to those of nail fungus can also be caused by conditions such as

• nail psoriasis,
• eczema of the nails,
• lichen ruber, and
• congenital or acquired chronic nail dystrophies.

Nail fungus can be completely cured, but treatment is a lengthy process. In many cases, it takes several months. Fingernail fungus clears up faster than toenail fungus.

The key to proper treatment of nail fungus is

• the clear identification of the fungal genus and
• the severity of the fungal infection.

Nail fungus can generally be treated with antifungal medications or laser therapy.

Home remedies such as tea tree oil, vinegar, or even your own urine have no proven clinical effect. Instead, they waste valuable time during which you could already be treating the nail fungus effectively.

Treatment of Nail Fungus with Antifungals

The most important treatment method is medication with so-called antifungals. These are antifungal medications that kill the causative fungal pathogens

• (fungicidal antifungals) or
• inhibit their growth (fungistatic antifungals)

.

Antifungals can be administered either topically, directly to the affected area, or in tablet form. When applied topically—for example, with nail polish—this is referred to as topical therapy. Taking tablets affects the entire body, which is why this is referred to as systemic therapy.

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Whether topical or systemic therapy is used depends on the extent of the nail fungus infection.

If the nail fungus affects less than 50 percent of the nail, topical therapy with fungistatic or fungicidal antifungal medications can be initiated. These are often available over the counter at pharmacies.

The clear nail polish is applied daily in the evening to the affected nail and the surrounding skin for several weeks. In addition to its active ingredients, the nail polish also protects the skin from moisture. This reduces the risk of infection and the spread of the fungus.

In advanced stages of nail fungus, treating the nail surface alone often does not yield the desired results. In such cases, the fungus-infected nail is softened and removed using a keratolytic agent over a three-week period. A new nail can then grow in its place.

If more than three toenails are infected with nail fungus, systemic therapy is recommended. The active ingredient, administered in tablet form, can spread throughout the entire body via the bloodstream.

The duration of systemic treatment ranges from three to six months, depending on the severity and resistance of the nail fungus. In special cases, therapy may be continued for longer periods at intervals.

In most cases, local treatment of the nail is also performed.

Laser Therapy for Treating Nail Fungus

Laser therapy is a relatively new method for effectively treating nail fungus.

The affected nail is irradiated using a pulsed Nd:YAG laser. This inactivates the existing fungal spores. This painless procedure, which takes only a few minutes, does not damage the nail.

If you are considering laser therapy, you should find out the costs in advance. Laser therapy is not covered by health insurance.

Laser therapy can eliminate fungal spores © hedgehog94 | AdobeStock

Without appropriate treatment, a nail fungus infection generally does not heal on its own. Rather, if left untreated, it progresses slowly and becomes chronic.

Nail fungus should therefore always be treated consistently. If treatment is discontinued or not carried out properly, there is a risk that fungal pathogens will remain and the nail fungus will spread again.

With proper treatment, nail fungus generally has a good prognosis and usually heals completely.

However, treatment for a fungal nail infection can be very lengthy and may take up to a year. Once the infection has cleared up, targeted measures can be taken to prevent a recurrence.

The risk of contracting nail fungus can be reduced relatively effectively by following a set of guidelines and taking preventive measures.

Measures for Personal Protection

These include, in particular,

• proper hygiene and nail care,
• wearing the right socks and shoes,
• avoiding common sources of infection, and
• strengthening the body’s immune system.

Regularly washing and caring for your feet prevents germs from entering the nail. Therefore, you should wash your feet daily with warm water and mild soap and apply a special moisturizing lotion.

Well-fitting shoes should be made of a breathable material that quickly wicks away moisture from the feet. Shoes made of leather or modern microfibers are particularly well-suited. Synthetic materials, on the other hand, are not recommended. Feet and toes must not be constricted.

Disinfecting your shoes at regular intervals helps kill the germs responsible for nail fungus.

Be sure to wear socks when trying on shoes. Socks should be made of natural materials such as wool or cotton and washed at 60 degrees. Socks made of synthetic materials can facilitate and promote the growth of nail fungus pathogens.

Towels, bath mats, and bedding should be washed at 60 degrees. At this temperature, the pathogens that cause nail fungus are killed.

In public facilities such as saunas, swimming pools, locker rooms, gyms, or hotels, you should always wear shower shoes. Afterward, it is recommended that you wash and disinfect your feet thoroughly.

To strengthen your body’s immune system, you should adopt

• a healthy lifestyle,
• a balanced and varied diet, and
• regular exercise.

When getting a manicure or pedicure, proceed with caution to prevent injuries to your nails. These can provide an easy entry point for fungal pathogens and thus promote the development of nail fungus.

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Measures to protect others

These precautions also prevent the spread of nail fungus if an infection is already present.

All objects and surfaces that have come into contact with the infected nail should be thoroughly cleaned immediately after use and, if possible, disinfected. These include, for example:

• Floors,
• carpets,
• door handles,
• used nail clippers or files,
• computer keyboards,
• towels,
• shoes, etc.

Always keep your nails short. This also prevents ingrown nails. Disinfect the nail clippers after use. Healthy nails must not come into contact with the unsterilized clippers.

People with nail fungus should always use their own towel and wear slippers. Do not visit swimming pools or saunas during the acute phase of a nail fungus infection.

Shoes should be thoroughly disinfected with an antifungal agent after each use. Leather shoes are more suitable, as the breathable material wicks moisture away from the foot. Using shoe polish helps keep moisture from penetrating from the outside.

Shoes, as well as ski boots, rollerblades, and rubber boots, should not be shared with others.