Nail fungus is commonly caused by microscopic fungi (called dermatophytes) that enter your toenails, fingernails, and even the skin under your nail (called the nail bed) through small cuts and cracks in the nail or on the surrounding skin. Nail fungus infection happens when there is an overgrowth of these dermatophytes.

There are several treatment options available for nail fungal infection. Choosing which one to undergo depends on the severity of the case. For mild to moderate cases of onychomycosis, over-the-counter and prescription-only oral medications and topical solutions are available. For severe cases, non-surgical procedures (like laser treatments) and surgical procedures (like avulsion) can be done to the infected nail(s). However, because these fungi are often stubborn to cure, a recurrence of the nail fungus infection is still highly possible even after treatment. Precautionary steps such as proper hygiene and regular application of a recommended topical solution is advised to avoid an onychomycosis relapse.

When diagnosing a fungal nail infection, a medical specialist (such as a dermatologist or a podiatrist) would have to rule out other relevant conditions because of some similarities in their symptoms. The next section discusses these other conditions often confused or mistaken with onychomycosis.

Nail fungus typically develops when there is an overgrowth of dermatophytes (a kind of pathogenic fungi that can grow on skin areas and cause skin diseases) in, on, or under the nail. In a few cases, it can also be caused by non-dermatophytic molds and Candida yeasts.

Dermatophytes, mold spores, and yeasts can penetrate the nail through small cuts in the skin surrounding your nail, a crack in your nail, or any separation between your nails, fingers, or toes. Under warm and moist conditions, these microorganisms can thrive and rapidly grow. They will feed on the keratinized tissue of the nail in order to nourish themselves. Aside from that, they will also produce byproducts that are harmful for the nail structure which causes the infection, the changes, and the degradation of the nail. As the fungal colony grows, the rate in which the nail host becomes damaged also increases. Meanwhile, as the body tries to repair the damage that’s happening on the nail, it will increase its production of keratin on the affected area. This in turn is what makes the nail thickened. Eventually, if left untreated and the growth of the fungal colony continues, the nail may become too weak to support itself and can lead to it falling of. In some severe cases, the infection may also cause pain.

A more detailed discussion of the causes of nail fungal infection is discussed in the next section.

An overgrowth of pathogens in your nail area causes nail fungus. As fungus (a kind of pathogen) thrive in warm and moist environments, the feet are more prone to getting in contact with fungus (i.e. by wearing sweaty socks in tight shoes for a long time or by walking barefoot on wet and humid places like the public sauna, spas, community pools, etc.). The toes also have less blood flow than the fingers, which makes it harder for the body’s immune system to detect and block the infection. Thus, toenail fungal infection is more common, and it typically occurs in about 10% - 20% of the adult population. However, the occurrence of fingernail fungal infection is still possible if fingers are constantly kept wet or damp and if they are exposed to dermatophytes.

Pathogens typically infect a nail by penetrating it through small cuts in the skin surrounding your nail, a crack in your nail, or any separation between your nails and fingers or toes.

If left untreated, your the condition may become more severe. Fungal infections are also very contagious and can spread to your other nails and skin.

One or a combination of the three types of pathogens can cause nail fungal infections. These pathogens are dermatophytes, candida, and non-dermatophytes. Dermatophytes are the most common cause of onychomycosis. Candida and molds cause 8% and 2% of fungal nail infections respectively.

The skin’s outer layer typically has the ability to discourage microorganism’s colonization. Shedding of epidermal cells also helps in avoiding microbes’ growth. However, due to trauma, maceration, and irritation, the skin’s protection mechanisms may fail. This results to susceptibility to infections.

This is the most common type of fungal nail infection, and it is usually caused by trichophyton rubrum, a dermatophytic fungus. DSO starts on the end of the nail bed and the underside of the nail plate. It may be difficult to treat this completely, and can become a lifelong condition.

In some instances, DSO may be caused by wearing closed shoes that fit too tightly for prolonged periods of time. Once the infection starts, wearing closed shoes might become uncomfortable and make the infection worse.

The progression of DSO includes:

• The nail often turns yellow or white partially or completely
• Pieces of debris made up of skin and nail fragments begin to build up under the nail
• The nail may eventually crumble, split and disengage from the nail bed
• Thickened nail

White Superficial Onychomycosis (WSO)

This condition makes up 10 percent of nail fungal infection cases and is most commonly caused by Trichophyton mentagrophyte, another type of dermatophytic fungus.

It occurs on the uppermost layer of the nail plate and usually affects the toenails. WSO can be treated quickly.

The signs associated with WSO include:

• Opaque white spots or ‘islands’ on the nail’s surface
• The whole nail might eventually turn white, soft and crumbly

Proximal Subungual Onychomycosis (PSO)

Proximal Subungual Onychomycosis is another type of nail fungus which is also caused by dermatophytes, usually trichophyton rubrum in particular. PSO occurs on the proximal nail fold (skin at the nail fold) and may penetrate the nail plate.

This condition may affect the fingernails and toenails in equal frequency. It commonly occurs in people with compromised immune systems and is considered one of the symptoms of human immunodeficiency virus (HIV) infection. It may also develop due to nail trauma.

PSO may appear in the following ways:

• Thickened skin at the nail fold, which may cause the skin to separate from the nail
• The nail color may become opaque white

Candida Infections of the Nail

Otherwise known as yeast infection of the nail, this condition is less common and may also affect the skin around the nail. It occurs more frequently on the fingernails than the toenails, and may invade nails weakened by previous infection or trauma. People who habitually immerse their hands in water are at high risk of developing this type of nail fungus infection.

Candida onychomycosis is usually characterized by:

• Separation of the nail from the nail bed (onycholysis)
• Discoloration of the nail- color might turn to white, green or brown
• Abnormality of the nail shape
• Thickened nail
• The skin around the nail (nail fold) may become swollen and tender
• The site of the infection may become painful

Total Dystrophic Onychomycosis

This condition refers to the complete destruction of the nail plate and may be the end result of any of the four types of nail fungus infection above.

In order to run laboratory tests to confirm diagnosis, samples should be collected from the infected nails. The sample collection process begins with thorough cleansing of the infected nail area and surrounding skin with 70% alcohol to eliminate other contaminants.

Obtaining optimal nail specimens depends on the presumptive diagnosis and site of the infection. The following approaches are recommended:

After collecting infected nail samples and skin scrapings, specimen analysis and antifungal susceptibility tests are conducted. First, the laboratory experts will examine the nail and skin scrapings to identify the type of organism that causes your infection. Below is a thorough discussion of these examinations.

Microscopy, staining, and culturing procedures may take up to six weeks before results can be received. Another generic test called the polymerase chain reaction (PCR), a method of detecting dermatophytes, delivers results within hours. The main approaches of laboratory confirmation of the diagnosis are the following:

• Potassium hydroxide smear
• Culture
• Histology

These comprises of the microscopic examination and culture of the obtained nail and skin debris. In identifying nondermatophyte molds, collecting several samples may be required. Results from these tests will strengthen the diagnosis and are also vital to formulating the proper treatment plan.

As mentioned in an earlier section, a dermatologist (skin doctor) or a podiatrist (foot doctor) will start with a physical examination of the infected toenail or fingernail. Debris under the nail, a portion of the nail, or affected skin tissues may be collected for further microscopic testing and culture. The test will be able to determine the cause of the infection: fungus, yeast, or molds.

How to Know What Type of Treatment Would Work Best for You?

In the recent years, there has been a more optimistic outlook on the treatment outcome of patients with nail fungus due to the introduction of promising new options, such as itraconazole, terbinafine and fluconazole. A personalized treatment plan that factors in a patient’s profile, symptoms, infection type, drug toxicities and interactions, is shown to result to improved success rates.

Below, we explore more details about the available treatment options.

Compared to other acute and chronic medical conditions, nail fungus infection might not seem like a highly threatening or dangerous disease. Since the infection is not particularly painful, affected individuals might consider it as a purely cosmetic concern and delay seeking advice from their health providers.

However, the longer you wait before treating your condition, the harder it will be to heal successfully. Ignoring a nail fungus infection can lead to serious consequences as the fungus progresses and may cause negative symptoms beyond the aesthetics:

As the infection grows from the tip towards the cuticle, the nail becomes thickened, discolored, brittle, and eventually appears deformed or misshapen. When this happens, it might lead to discomfort and pain when walking and putting on closed shoes.

Onycholysis– a condition characterized by the separation of the nail plate from the nail bed can also occur. The loose portion or the entire nail may then either fall off on its own or will have to be removed in an avulsion procedure (discussed in detail in the Treatments section). This might lead to the permanent loss of the nail or in more severe cases, several toenails or fingernails.

Fungal infections are highly contagious and can easily spread to the skin surrounding the affected nail and to the other nails as well. The skin might become inflamed, itchy, dry, and cracked — and lead to athlete’s foot or tinea pedis. Athlete’s foot causes skin peeling, stinging, blisters, and sores.

Wearing socks and closed shoes for prolonged periods of time can cause the infection to spread quickly, once one of the toenails has been affected.

Keeping a harmful organism alive in your nail can cause the infection to migrate to other parts of the body, such as hands, back, and legs. It can also spread to the genitals, inner thighs and buttocks — in a condition called jock itch. Jock itch is characterized by a red, itchy, and usually ring-shaped rash.

One in every two dozen cases of nail fungus infections results to the spread of the infection to other parts of the body. Older people or those with weakened immune systems are especially susceptible to this.

The fungus can create cracks, chips, and openings in the nail and skin, where bacteria can get in and cause a condition called paronychia (whitlow). It usually enters through a break in the skin between the nail fold (cuticle) and the nail plate.

Paronychia can either be acute or chronic: Acute paronychia develops quickly and is usually caused by the Staphylococcus bacteria, while chronic paronychia occurs slowly and is commonly caused by more than one infecting agent, typically Candida yeast and a bacteria.

Symptoms include:

• Red and tender skin around the nail
• Abnormalities in skin shape, color, or texture
• Blisters
• Detachment of the nail plate from the nail bed

Acute paronychia may be treated using home remedies, and oral or topical antibiotics; while chronic paronychia is harder to treat and may require antifungal medication or even nail removal, in very severe cases.

Bacteria that entered through the cracks and openings in the nail and skin can cause widespread infection in the body. This may lead to cellulitis — a bacterial skin infection that is potentially serious, even deadly, when it spreads into the underlying tissues, lymph nodes, and the bloodstream.

Symptoms of cellulitis include:

• Swollen, inflamed area in the skin that tends to expand or change rapidly
• The area feels warm and tender to the touch
• Fever
• Blisters
• Can spread quickly on different parts of the body
• Usually appears on one side of the body

Cellulitis can have especially serious consequences for people with diabetes, nerve damage, circulation problems, or weakened immune system. It is associated with increased risk of diabetic amputation.

It is strongly recommended that individuals seek immediate medical attention on the first sign of cellulitis, as the infection can cause rapid widespread infection and lead to serious internal damage or even fatality.

Given the stubborn nature of nail fungus infection, it is best to take a proactive approach to minimize the chance of its occurrence.

As discussed in the above section (Section II: Nail Fungus Cases — Risk Factors), certain people, such as swimmers and those who have diabetes, have a higher likelihood of contracting the infection. People who have suffered from it before are also at high risk of getting it again — as recurrence rate is at 10% to 50%, despite treatment.

It would be wise, especially for these individuals, to take extra precaution to avoid the hassle, costs, and worries of having to deal with nail fungus infection.

The adage that whatever you put inside your body manifests on the appearance of your hair, skin, and nails is true.

An antifungal diet gets rid of food ingredients that fungal parasites can feed on and in the process, reduces inflammation inside the body. Eliminating sugar and conventional grain products from your diet means starving the parasites and can lead to their death.

Pay special attention if you have specific food allergies, as they can cause inflammation and adverse reactions (such as fungal and yeast growth) inside your body. The list of the most allergenic food includes: dairy, eggs, peanuts, and tree nuts (cashew, walnuts), seafood, wheat (gluten), and soy.

Though not yet backed by medical research, many individuals report good results from taking probiotic supplements. The good, beneficial bacteria provided by probiotics may strengthen the anti-fungal properties of good bacteria that we already have on our skin and help prevent fungal infection from occurring. A weakened immune system is more susceptible to fungal infections, so make sure that you get the right nutrients everyday. You might want to take a good quality multivitamin that contains Vitamin A, Vitamin C, Vitamin D, zinc, and other essential vitamins and minerals.

B. Lifestyle and Environment

Good hygiene is key to preventing nail fungus infection, so it is important to always keep your feet and hands clean and dry.

Here are some other simple practices you can adapt to minimize the risk of contracting nail fungus infection:

It is frustrating to have to deal with recurrent cases of fungal nail infection. Apart from the tips given above, you can add the following practices to avoid reinfection:

Bad news for those who love to get their nails done in salons: it can put you at increased risk of getting nail fungus infection. The fungus can spread through the following ways:

• Direct contact between clients
• When the nail technician does not sanitize her hands between servicing different customers
• It can be passed on through the shared nail tools, especially if they are not properly sanitized between uses.

The good news is: it is easy to do your own manicure and pedicure at home. You can avoid the hazards associated with getting your nails done in public salons/spa, and this will help you to save on costs too.

It helps to be armed with the right information in your battle against the stubborn nail fungus infection.

Based on our intensive research, these are the most helpful online resources on the condition: