How to Identify the Different Types of Toenail Fungus Infections

There are a total of four well-known and well-studied kinds of fungal toenail infection. Each is subtly different to the others, although it can be difficult differentiating between them. That’s why we’ve created this in-depth guide so that you can identify it quickly.

Some kinds of fungal toenail infection are more common than others. This is because they have an easier time spreading between an infected person and a non-infected person. Another reason is that the fungus itself can reproduce more quickly and spread faster among people.

Again, some of the types of fungal toenail infection are more severe than the other kinds. They differ in how they affect the nail and nail bed, and some of them are more painful. You have to treat these types of fungal toenail with different methods.

Before examining the different forms of fungal toenail infection, have you considered that your toes aren’t infected? That’s right: even though your nails may appear to have contracted fungus, there’s a good chance they haven’t.

Somewhere around half of suspected infections are completely free of fungus.

Instead, a large portion of people has nail dystrophies. This common deformity has a similar appearance to fungal infection but is a genetic and non-catching condition. As such, the problem is purely cosmetic and doesn’t require treatment (unless it affects your confidence).

Onychomycosis is also easily confused with a number of other nail disorders, such as:

  • General bacterial infections, which can turn the nail a black or green color
  • Psoriasis, eczema, and dermatitis, which can all affect fingernails and toenails
  • Mold or lichen, which can affect the nails (although rarely)
  • Onycholysis and onychogryphosis, both conditions of the nail with similar symptoms, but different causes

The American Academy of Dermatology recommends consulting a podiatrist before any treatment for your fungal toenails. This is because the oils, ointments, and creams used to get rid of fungus can have side effects. This is particularly true of oral treatments, which are commonly prescribed by podiatrists and dermatologists.

Of course, a large proportion of people will experience a fungal nail infection in their lifetime. So if you do suspect that you have an infection, ask your doctor for a diagnosis. But before you go and do that, take a look at our guide for the most common symptoms.

At the very beginning of a fungal toenail infection, there are no visible symptoms. But as the infection progresses, some signs should make your condition obvious. The symptoms that are common among almost all infections are as follows:

  • Discoloration of your toenail, whether it turns white, black, yellow or green
  • A change in the texture of your nail, whether it becomes more brittle or softer
  • Distortion of your nail as its shape and texture change
  • Crumbling of your nail as parts break away
  • General pain and discomfort, not necessarily to the point where you can’t walk, but if you put pressure on your nail

Fungal nail infections also have a number of common causes, although some causes are unique to certain infections.

These common causes are as follows:

  • Choosing, or not being able, to keep your feet clean and dry
  • Wearing shoes that leave your feet feeling sweaty
  • Walking around barefoot at the swimming pool or gym

On the other hand, there are some vectors which are unique to certain kinds of infection.

  • Damaging your nails allows for Candida onychomycosis to infect your toenails
  • Having a weakened immune system allows proximal subungual onychomycosis to take hold, as do having other health conditions like diabetes or heart disease. This is because of your compromised immune system.

Types of Toenail Fungus Infections

If you can pinpoint how you contracted your fungal infection, this may allow you to achieve a diagnosis. At the same time, if you have proximal subungual onychomycosis, this may also be a sign of further illness. In this instance, you should consult a doctor not just for a fungal toenail diagnosis, but a general diagnosis.

Distal Subungual Onychomycosis (DSO)

Distal subungual onychomycosis is by far the most common kind of toenail fungus. It’s also one of the most unpleasant forms of fungal toenail infection, because of its long lasting symptoms. That being said, it can be tackled with appropriate and timely treatment, which we’ll come back to later.

What Are the Symptoms?

Distal subungual onychomycosis is caused by the very same fungus that causes athlete’s foot.  That means that it commonly affects people who already have athlete’s foot, or live with someone who does. So if you already have athlete’s foot, and you have recently contracted a fungal toenail, it’s probably DSO.

A DSO infection is characterized by a number of recognizable symptoms, each of which makes it difficult to treat. DSO infects the skin underneath the nail, which is also known as the nail bed. It first infects the very top of the nail, but quickly moves along the nail towards the bottom.

The infected nail will turn either yellow or white as the condition progresses. If left untreated, the nail will begin to crumble and split, which can cause pain. Debris also gets caught underneath the nail and is particularly hard to remove, which increases the pain.

The nail will also become thicker, and the texture of your nails will change as they lose flexibility. DSO affects the nail bed and is stubborn and difficult to treat, so can be a lifelong condition. But don’t worry, because even the worst fungal nail infection is treatable with enough time and effort.

What Are the Treatments?

Because it is a stubborn condition, your podiatrist may recommend a range of treatments. This could be up to and including removing a portion of the affected nail to prevent re-infection. Infections vary between patients.

Because of its stubborn nature, treatment for DSO will most likely take longer than other forms of infection.  If you receive laser surgery for toenail fungus, this will take an hour, and you will come in for repeat treatments. Your podiatrist will advise you on when they consider your treatment to have achieved its full effect.

White Superficial Onychomycosis (WSO)

White superficial onychomycosis is the next most common form of fungal infection, after DSO. White superficial onychomycosis, as per the name, is only superficial: it affects the nail, not the nail bed. This means that it is much quicker and much easier to treat, which is good news.

What Are the Symptoms?

The first sign of WSO is that small, white spots will begin to appear on the surface of your nail. Over time, the condition will progress until the surface is covered in crumbly powder.  That being said, you don’t need to let the condition affect the entire nail before seeking treatment.

Unlike DSO, the nail does not become any thicker over time, although the texture does change. And again, unlike DSO, the nail does not separate from the underlying nail bed. WSO is, therefore, less likely to become debilitating and painful, so it is considered far less serious.

White superficial onychomycosis is easily confused with a common condition which is not harmful, nor caused by fungus. WSO is commonly mistaken for keratin granulations which form as a reaction to nail polish in some people. This reaction causes a chalky, white substance to form on the nail, just like white superficial onychomycosis.

Because WSO does not infect the nail bed, you are far less likely to find walking and movement difficult. As such, whereas there is a chance that DSO may be covered by insurance, WSO certainly won’t be. But even so, you can still have it effectively treated by a podiatrist.

What Are the Treatments?

Because of its less serious nature, WSO is treated by ointments and creams, such as the Purely Northwest Toenail Fungus System. This is because the common side effects of oral medication are not considered worth treating the condition. Laser treatment is also a safe and non-invasive option for the treatment of WSO.

Even though it is less serious than subungual infections, it is still vital that you receive proper treatment. Any form of fungal infection progresses over time, spreads from nail to nail, and becomes more painful. It’s better to get treatment over with as soon as you possibly can, to prevent further spread.

Toenail Fungus Types

Candida Onychomycosis

Candida onychomycosis is relatively rare and is caused by a different mechanism than WSO and DSO.  CO is caused by a yeast infection, as opposed to a fungal infection, but can operate in the same way. It also has a number of similar symptoms, but there are tell tale signs that you’re suffering from CO.

What Are the Symptoms?

Infection with Candida begins with paronychia: literally, an inflammation and infection next to the nail. That means that the skin around the nail becomes infected before the nail itself is attacked. This method of infection is unique to candida onychomycosis, so it’s much easier to detect than other fungal infections.

From there, CO will begin to affect the nail itself, spreading from the sides of the nails to the center. Like other forms of infection, CO can affect several nails at the same time. It more commonly affects the fingernails than the toenails but is known to affect both.

CO (like DSO) can cause the nail to separate from the underlying nail bed, which is one of the most painful symptoms. Unlike other infections, however, CO changes the infected nail to a variety of different colors. The nail may become a discolored white, green, or brown, and may change shape over time.

The nail becomes thicker than normal and will show more general signs of infection like swelling and tenderness. The infection itself is more painful than the fungal forms of infection. The treatment is also different, both because of the infection’s severity and its different cause.

What Are the Treatments?

Just like DSO, the severity of Candida onychomycosis might mean that you need to undergo extensive treatment. This can mean taking oral medication, undergoing laser treatment and applying creams to the infected area. On the plus side, Candida onychomycosis is rare and therefore more difficult to catch in the first place.

Candida onychomycosis is caused by common yeast and is therefore contracted in the same way as athlete’s foot. It is water borne, which is why it spreads through exercise- sweat is an excellent medium for infection! It commonly affects those who regularly have their hands in water, such as dish water.

That’s why it doesn’t as often affect the feet, as they are submerged less often.

Proximal Subungual Onychomycosis (PSO)

Proximal subungual onychomycosis is caused by dermatophytes, the same keratin eating fungi that cause DSO and WSO. But unlike the other two fungal infections, PSO is specifically common in people who are infected with HIV.

What Are the Symptoms?

The difference between PSO and DSO is the location of the infection, as indicated by the name. ‘Proximal’ and ‘distal’ refer to two locations of the nail and nail bed, one near and one far. The proximal nail fold is also called the eponychium and is the section of skin that partially covers the lunula.

PSO is defined by the action of the fungus, not in attacking the distal nail edge, but the proximal nail fold. This means that the infection attacks the newest nail growth, immediately after it begins to show. This is a sign that the body is immunocompromised, i.e. that their immune system is not operating properly.

PSO is identified by the white appearance of the area around the lunula, to a greater extent than usual. Whereas the lunula is normally lighter than the rest of the nail, the base becomes opaque in PSO. The infection can also spread from the base of the nail to the surrounding area of skin.

Aside from these factors, the symptoms of PSO are broadly similar to those of DSO. The nail becomes white and opaque, the texture brittle and flaky, and the nail thicker than usual. The main differentiating factor is the location of the infection at the base rather than the tip.

What Are the Treatments?

Because it is broadly similar to DSO, the treatment is also similar. PSO can be treated with oral medication, creams, or laser treatment- or a combination of the above. However, you may not experience a similar recovery time: PSO is harder to treat than the other forms.

That’s because PSO is usually a sign of a more important medical condition, which inhibits immune system response. As such, it is unlikely that treatment will completely cure your PSO, as the condition will recur. It is important to talk to your doctor to prioritize your care, but they’re quite likely to recommend an over-the-counter product called Xenna Nonyx Nail Gel.

Of course, PSO is not necessarily a sign of an even more important condition. That’s why you may wish to visit your podiatrist for advice on the issue. They advise you on the prognosis of treatment, how long it will take, and whether it might recur.

What If I Can’t Tell What Kind of Infection I have?

Despite having information available online, it can still be difficult to diagnose your condition. This is because while the general rules above hold true, your case may not reflect that. You may also, believe it or not, have more than one infection – although that is exceedingly rare.

There is also little to distinguish between DSO and PSO, although this isn’t of much concern. They are each treated in the same way, so that isn’t a problem. The only distinction between the two is the location of the infection.

Even if you are fairly sure of what is wrong with your nail, we still advise seeking out a podiatrist for an initial diagnosis. They will be able to identify the specific cause, fungal or otherwise, of your toenail condition. They will then be able to tell you the right treatment.