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What is Nail Fungus? Symptoms, Causes, & Treatment

Created at:1/16/2025

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Nail fungus is a common infection that affects your toenails or fingernails, causing them to become thick, discolored, and brittle. This condition, medically known as onychomycosis, happens when tiny organisms called fungi find their way under your nail and start growing there. While it might feel embarrassing or concerning when you first notice it, nail fungus is incredibly common and completely treatable with the right approach.

What is nail fungus?

Nail fungus is an infection caused by microscopic organisms that thrive in warm, moist environments. These fungi eat keratin, the protein that makes up your nails, which causes the characteristic changes you see in infected nails. The infection typically starts small, often beginning at the edge or tip of your nail, then gradually spreads deeper if left untreated.

Your toenails are more likely to get infected than your fingernails because your feet spend more time in dark, warm, moist conditions inside your shoes. The infection can affect just one nail or spread to multiple nails over time, and it tends to be more stubborn than other types of fungal infections you might encounter.

What are the symptoms of nail fungus?

The early signs of nail fungus can be subtle, but they become more noticeable as the infection progresses. You might first notice a small white or yellow spot under the tip of your nail, which can easily be mistaken for a minor injury or stain.

As the infection develops, you may experience these common symptoms:

  • Thickening of the nail, making it difficult to trim
  • Yellow, brown, or white discoloration
  • Crumbly, brittle, or ragged nail edges
  • Distorted nail shape
  • A slightly foul smell coming from the infected nail
  • Separation of the nail from the nail bed
  • White or yellow streaks on the side of the nail

In more advanced cases, you might notice the nail becoming so thick that it causes discomfort when wearing shoes. Some people also experience mild pain or tenderness around the infected area, though nail fungus typically does not cause significant pain unless complications develop.

What are the types of nail fungus?

There are several different types of nail fungus, each with slightly different patterns of infection. The most common type is called distal subungual onychomycosis, which starts at the tip of your nail and works its way back toward the cuticle.

Other types include white superficial onychomycosis, which creates white patches on the surface of your nail, and proximal subungual onychomycosis, which begins near the cuticle and spreads outward. There is also candidal onychomycosis, caused by yeast rather than typical fungi, which often affects people with compromised immune systems.

Each type may look slightly different and respond differently to treatment, but the good news is that most antifungal treatments work effectively against all common types of nail fungus.

What causes nail fungus?

Nail fungus develops when fungi find the right conditions to grow and multiply. These organisms are everywhere in our environment, but they particularly love warm, moist places where they can thrive undisturbed.

Several factors can create the perfect environment for nail fungus:

  • Wearing tight, non-breathable shoes that trap moisture
  • Having sweaty feet or hands
  • Walking barefoot in public pools, showers, or locker rooms
  • Having a minor nail injury that creates an entry point
  • Sharing nail clippers, files, or other personal items
  • Having poor circulation in your hands or feet
  • Living in a humid climate

Sometimes, nail fungus can spread from other fungal infections on your body, such as athlete's foot. The same fungi that cause skin infections can migrate to your nails, especially if you touch the affected skin and then touch your nails without washing your hands.

When to see a doctor for nail fungus?

You should consider seeing a healthcare provider if you notice changes in your nails that concern you or if home treatments are not working. Early treatment often leads to better outcomes, so do not feel like you need to wait until the infection becomes severe.

Definitely schedule an appointment if you experience pain, notice signs of a bacterial infection like pus or red streaking, or if the infection is spreading to multiple nails. People with diabetes, circulation problems, or weakened immune systems should see a doctor promptly, as nail infections can lead to more serious complications in these cases.

It is also worth getting a professional opinion if you are unsure whether your symptoms are actually caused by nail fungus, since other conditions can cause similar changes to your nails.

What are the risk factors for nail fungus?

While anyone can develop nail fungus, certain factors can make you more susceptible to infection. Understanding these risk factors can help you take preventive steps and recognize when you might be at higher risk.

Age is one of the biggest risk factors, as nail fungus becomes more common as you get older. Your nails grow more slowly with age and become thicker, making them more vulnerable to infection. Reduced blood circulation and a weakened immune system also contribute to increased risk as you age.

Other factors that increase your risk include:

  • Having diabetes or circulation problems
  • Taking immunosuppressive medications
  • Having a history of athlete's foot
  • Excessive sweating (hyperhidrosis)
  • Working in a humid environment
  • Having psoriasis or other skin conditions
  • Living with someone who has nail fungus
  • Participating in activities that involve prolonged moisture exposure

Men are generally more likely to develop nail fungus than women, and having a family history of fungal infections can also increase your risk. If several of these factors apply to you, taking extra preventive measures becomes especially important.

What are the possible complications of nail fungus?

Most nail fungus infections remain relatively minor and do not cause serious health problems. However, if left untreated for a long time, some complications can develop that may require more intensive treatment.

The infection can spread to other nails on the same hand or foot, and in some cases, it can spread to the surrounding skin. This is particularly concerning if you have athlete's foot alongside nail fungus, as the two conditions can feed into each other in a cycle of reinfection.

For people with certain health conditions, complications can be more serious:

  • Bacterial infections developing in damaged nail tissue
  • Cellulitis (spreading skin infection) in people with compromised immune systems
  • Permanent nail damage or loss
  • Difficulty walking due to thick, painful nails
  • Secondary skin infections from scratching

People with diabetes face additional risks because nail fungus can create open wounds that heal poorly and become infected. If you have diabetes and notice any signs of nail fungus, it is important to address it promptly with your healthcare provider.

How can nail fungus be prevented?

Preventing nail fungus is often easier than treating it, and most prevention strategies involve keeping your hands and feet clean and dry. Good hygiene habits can significantly reduce your risk of developing an infection.

Start by keeping your nails clean and trimmed short, cutting them straight across to prevent ingrown nails that can create entry points for fungi. Always wash your hands and feet regularly, and dry them thoroughly, especially between your toes.

Here are key prevention strategies that can help:

  • Wear breathable shoes and change socks daily
  • Use antifungal powder in your shoes if you sweat heavily
  • Wear shower shoes in public pools, gyms, and locker rooms
  • Do not share nail clippers, files, or other personal items
  • Choose nail salons that sterilize their tools properly
  • Treat athlete's foot promptly to prevent spread to nails
  • Wear gloves when doing wet work or using harsh chemicals

If you are prone to fungal infections, consider using antifungal sprays or powders regularly, especially during humid weather or when you will be in high-risk environments like gyms or pools.

How is nail fungus diagnosed?

Diagnosing nail fungus typically starts with a visual examination by your healthcare provider. They will look at the affected nails and ask about your symptoms, medical history, and any recent activities that might have exposed you to fungi.

However, since other conditions can cause similar nail changes, your doctor may want to confirm the diagnosis with laboratory tests. They might take a small sample of nail clippings or scrape some debris from under your nail to examine under a microscope or send to a lab for culture testing.

These tests help identify the specific type of fungus causing your infection, which can guide treatment decisions. The process is quick and typically painless, though you may feel slight pressure when the sample is collected. Results usually come back within a few days to a week, depending on the type of test performed.

What is the treatment for nail fungus?

Treatment for nail fungus requires patience, as nails grow slowly and the infection can be stubborn. Your healthcare provider will recommend the best approach based on the severity of your infection, your overall health, and your preferences.

Topical antifungal medications are often the first line of treatment for mild to moderate infections. These come as creams, gels, or nail lacquers that you apply directly to the affected nail. While they have fewer side effects than oral medications, they may take longer to work and are not always effective for severe infections.

For more extensive infections, oral antifungal medications are usually more effective. These prescription pills work from the inside out, reaching the infection through your bloodstream. Treatment typically lasts several months, and you will need periodic blood tests to monitor for potential side effects.

Other treatment options include:

  • Laser therapy, which uses focused light to target fungi
  • Nail removal in severe cases to allow direct treatment of the nail bed
  • Combination therapy using both topical and oral medications
  • Photodynamic therapy, which combines light with special chemicals

Your doctor will work with you to choose the treatment approach that makes the most sense for your situation, considering factors like your age, overall health, and how bothersome the infection is for you.

How to take home treatment during nail fungus?

While professional treatment is often necessary for nail fungus, there are several things you can do at home to support your recovery and prevent the infection from getting worse. These home care measures work best when combined with prescribed treatments, not as replacements for them.

Keep your feet and hands as clean and dry as possible throughout your treatment. Wash them daily with soap and water, then dry thoroughly, paying special attention to the areas between your toes. Change your socks daily, and choose moisture-wicking materials when possible.

Here are helpful home care strategies:

  • Trim infected nails short and file down thick areas gently
  • Disinfect nail clippers and files after each use
  • Apply prescribed medications exactly as directed
  • Wear breathable footwear and alternate shoes daily
  • Use antifungal powder in your shoes
  • Replace old shoes that may harbor fungi
  • Wear clean socks made of breathable materials

Some people find soaking their feet in warm water with Epsom salt helpful for softening thick nails and improving the penetration of topical medications. However, always check with your healthcare provider before trying home remedies, as some can interfere with prescribed treatments or cause irritation.

How should you prepare for your doctor appointment?

Preparing for your appointment can help ensure you get the most out of your visit and receive the best possible care. Start by making a list of all your symptoms, including when you first noticed changes in your nails and how they have progressed over time.

Bring a complete list of all medications you are currently taking, including prescription drugs, over-the-counter medications, and supplements. This information helps your doctor choose the safest and most effective treatment options for you.

Consider writing down questions you want to ask, such as:

  • What type of nail fungus do I have?
  • What treatment options are available?
  • How long will treatment take?
  • What are the potential side effects?
  • How can I prevent reinfection?
  • When should I expect to see improvement?
  • Do I need follow-up appointments?

If possible, avoid applying nail polish or artificial nails before your appointment, as these can make it harder for your doctor to examine your nails properly. Also, think about whether you have been exposed to fungi recently or if family members have similar infections.

What's the key takeaway about nail fungus?

Nail fungus is a common, treatable condition that affects millions of people. While it can be persistent and take time to clear completely, effective treatments are available, and most people can achieve clear, healthy nails with proper care and patience.

The most important thing to remember is that early treatment generally leads to better outcomes. If you notice changes in your nails that concern you, do not hesitate to seek professional advice. Your healthcare provider can help determine the best treatment approach for your specific situation.

Prevention remains your best defense against nail fungus. By maintaining good hygiene, keeping your nails clean and dry, and avoiding high-risk situations, you can significantly reduce your chances of developing an infection. If you do develop nail fungus, remember that it is a medical condition, not a reflection of poor hygiene, and effective treatment is available to help you regain healthy nails.

Frequently asked questions about Nail Fungus

Yes, nail fungus can be contagious, but it does not spread as easily as some other infections. You can catch it by direct contact with infected nails or by walking barefoot in areas where fungi thrive, like public showers or pools. However, not everyone exposed to the fungus will develop an infection, as individual susceptibility varies.

Treating nail fungus requires patience, as it typically takes several months to see complete results. Toenails usually take 12 to 18 months to grow out completely, while fingernails take about 6 months. You should start seeing improvement within the first few months of treatment, but complete clearance takes time as the healthy nail grows out.

It is generally better to avoid regular nail polish during treatment, as it can trap moisture and make the infection worse. However, some antifungal nail lacquers are specifically designed for treating nail fungus. If you choose to use regular polish occasionally, make sure to remove it completely and let your nails breathe between applications.

Nail fungus rarely goes away without treatment. In fact, it typically gets worse over time if left untreated, potentially spreading to other nails or causing complications. While some very mild infections might improve with aggressive hygiene measures alone, most cases require antifungal treatment to clear completely.

Nail fungus can recur if the underlying conditions that led to the initial infection are not addressed. This might include continuing to wear tight shoes, not keeping feet dry, or being exposed to fungi in your environment. Additionally, some people may be more genetically susceptible to fungal infections. Following prevention strategies and completing the full course of treatment can help reduce the risk of recurrence.

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