What causes nail fungus : how it develops!

What causes nail fungus : how it develops!

Table of Contents

What is the most common cause of nail fungus?

Is nail fungus contagious?

How can I avoid a fungal nail infection?

Here you can find out.

Formation of nail fungus

Nail fungus also called onychomycosis (onycho = nail, mycosis = fungal disease), is the most common disease of the nails.

It usually arises from infection with dermatophytes (filamentous fungi, especially Trichophyton rubrum), rarely also from yeasts or molds.

These fungi are parasites that feed on the keratin on our skin and nails. The nail fungus can occur on both feet and hands. In itself, nail fungus is not dangerous as long as it is treated on time. 

In many cases, the nail fungus develops on the nail of the big toe. But it can also spread to the surrounding toes and affect several nails.

The toenail fungus usually grows from the front edge of the nail bed to the skin below the nail plate (hyponychium).

From there, it spreads further in the direction of the nail matrix. You can see precisely what nail fungus looks like on the nail fungus symptoms pageThere, I posted pictures of infected nails for you.

As already mentioned, both the nails of the fingers and the feet can be affected, but toenails are affected four times more often than fingernails.

This is because a dark, humid and warm environment (as it occurs in many shoes) strongly favors the growth of the fungi.

It offers the ideal living conditions for the fungus to develop. There are several causes of nail fungus. In the next section, I would like to show you the most common ones.

Is nail fungus contagious?

Nail fungus is a contagious disease! If a person has onychomycosis, they can also infect other people with the fungal infection. A distinction is made between two types of illness:

  • Contact infection
  • Indirect smear infection

With contact infection, the nail fungus pathogen is transmitted through direct skin contact with an infected person.

This is different from the more common indirect smear infection: Here, the pathogen is transmitted via shared objects such as shoes and floors.

This is possible because the infection is transmitted through skin flakes, which everyone loses in large numbers. The fungal spores can survive for days and weeks on the skin flakes!

For the reasons mentioned above, the risk of infection is significantly increased in places where people walk barefoot.

In general, public facilities such as swimming pools shared changing rooms, and showers are potential places of contagion.

But also in hotel rooms, you should be careful of toenail fungus. To prevent infection, we recommend wearing socks, slippers, or flip-flops. 

If a person in your household suffers from nail fungus, there is also a high risk of infection here.

For example, if you use the same towels, you can become infected. The same applies to the everyday use of nail care sets, e.g., nail scissors or files.

Risk factors favor a fungal nail infection.

The fungal spores lurk in many places and are looking for a new host. If you come into contact with the pathogen, a healthy immune system can often fight off the pathogen. If the skin and nails are healthy and not injured, there is the perfect protection against nail fungus.

However, certain risk factors promote nail fungus disease:

  • Advanced age
  • Underlying conditions such as psoriasis and diabetes
  • Circulatory disorders
  • Weak immune system
  • Existing athlete’s foot disease
  • Micro-injuries from sports and tight shoes
  • Increased perspiration
  • Improper nail care
  • Genetic predisposition and foot deformitie

 Risk factor: advanced age

Due to their age, the grandparents have an increased risk of developing nail fungus.
Due to their age, the grandparents have an increased risk of developing nail fungus.

Infection of the nails is much more likely in the age group 65 and over. Almost every second of this group is affected by nail fungus. One reason for this is an age-related, poorer structure of the nails and the surrounding tissue.

In addition, the immune system is often no longer strong enough because older people often suffer from numerous diseases. Some drugs may have to be taken that suppress the immune system.

Calcified blood vessels (arteriosclerosis) reduce the blood flow to the limbs and make older people even more susceptible to infection. In addition, there is usually also a deterioration in the texture of the skin with increasing age.

The skin becomes drier, thinner, and more often suffers from cracks. The condition of the nails is getting worse and worse. All of these reasons lead to a significantly increased risk of developing nail fungus.

Risk factor: underlying diseases such as psoriasis and diabetes

People with diabetes are particularly susceptible to developing nail fungus. There are two reasons for this. On the one hand, the blood circulation is often poor, and, on the other hand, the immune defense is restricted.

In addition, toenail fungus is often diagnosed late in diabetics, as painful symptoms are often not noticed due to nerve damage. People with diabetes should have their feet checked regularly or have their feet checked by a foot care provider to treat an infection as soon as possible.

Psoriasis also promotes the development of onychomycosis. The inflammatory skin disease can also appear on the nails and is called nail psoriasis. Fungal infections can also occur due to the excessive formation of skin cells and nail tissue, including inflammation.

Risk factor: existing athlete’s foot disease

An itchy or burning sensation between your toes or the soles of your feet can be a symptom of athlete's foot.

A previous untreated illness of an athlete’s foot is often the cause of a fungal nail infection. In this case, the fungus spreads along with the toes and eventually infects the toenails.

Therefore, the athlete’s foot treatment should be started immediately after the diagnosis by the doctor, before it also develops nail fungus.

Risk factor: weak immune system

The first two risk factors also refer to the immune system. The body’s defense mechanisms protect the body from harmful substances and pathogens. The body is confronted with viruses, bacteria, and also fungi daily.

For this reason, people who suffer from immunodeficiency are particularly at risk of a fungus invading and causing nail fungus. If there is an HIV infection, the immune system is also severely impaired. Certain drugs deliberately suppress the immune system, e.g., as part of cancer therapy or an organ transplant. Risk factor: circulatory disorders

All diseases that lead to circulatory disorders increase the risk of a fungal infection. This is because the feet and hands are poorly supplied with oxygen and essential nutrients.

Smoking is also one of the risk factors as it affects blood circulation and weakens the immune system.

Risk factor: micro-injuries caused by sports or tight shoes

The skin plays a central role in the immune system. If the skin on the toes and fingers is healthy, it is difficult for germs to enter the body. However, if the skin on the feet is injured, the fungus has an easy job.

These tiny injuries to the skin can occur again and again during sport. Runners are particularly at risk, as blisters often form on both inexperienced and long-distance runners’ toes. When the blisters tear due to friction, this part of the body is a gateway for bacteria and fungi.

But all other athletes or people who suffer micro-injuries to their feet from shoes that are too tight and not fitting are at risk.

Risk factor: increased perspiration

Since the mushrooms need a warm and humid climate for their growth, increased sweat production is a favorable factor. Some people suffer from abnormally heavy sweating of the feet and are therefore in the risk group.

If, for example, work shoes are worn in which little air comes into contact with the feet, permanent, high production of sweat can occur. Breathable socks and shoes are recommended to reduce this risk.

By exercise, it is also increased bleeding at the foot in the shoe. Here, it is advisable to use more than just one pair of sports shoes, let them dry properly after training, and disinfect them regularly.

Risk factor: improper nail care

The nail is often injured if the nail is not properly cared for.
The nail is often injured if the nail is not properly cared for.

As mentioned earlier, healthy skin is significant for fighting off fungi. The pathogens that cause onychomycosis can enter the body much more quickly through minor wounds.

Minor injuries occur, for example, when too much is cut off the nail during nail care. In this case, the nail bed is exposed and accessible to intruders. The same problem exists when nail scissors or nail clippers injure the skin on the toes or fingers.

Artificial nails can increase the risk of nail mycosis. When attaching gel nails, too much is often filed away from the nail, representing an entry point for the nail fungus.

Risk factor: genetic predisposition and foot deformities

The genetic predisposition may also play a role in the risk of nail fungus infection. This is shown by recent studies. In addition to the children, parents and grandparents are often affected by the fungal disease.

Malpositions of the feet can increase the pressure on the toenails, leading to more frequent injuries to the skin and, thus, to a higher susceptibility to nail fungus.

Conclusion: causes of nail mycosis

There are many different causes of fungal disease. A few simple rules of conduct can significantly reduce the risk of infection.

Bathing shoes should always be worn in places with a high risk of infection, such as swimming pools or collective changing rooms!

Wear breathable socks and shoes and dry them thoroughly after use and disinfect them occasionally. 

A healthy, active lifestyle helps strengthen the immune system and blood circulation, which means that the body’s defenses can fight off the fungus.

If an infection does occur, it makes sense to start therapy immediately


What causes nail fungus : how it develops!
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