Thick nails can affect not only fingernails but also toenails. Affected nails can be unsightly or cause discomfort. If left untreated, thick nails can get worse and cause pain. There are many potential causes of thick nails. By understanding these causes, a person may be able to prevent thick toenails from forming and treat them quickly if they develop.

Fungal infection is a common cause of thick nails. If the nails change unexpectedly in terms of thickness, color or texture, it is important to see a doctor to rule out any underlying condition. Treatment depends on the severity of nail changes and the underlying cause. People can often prevent thick nails by avoiding infections and irritants and keeping nails dry. This article examines the causes, symptoms, prevention, and treatment options for thick fingernails and toenails.


Fingernails and toenails act as a strong barrier between the soft tissue in the nail bed beneath them and the environment behind them. Fingernails are useful for everyday tasks, such as scratching. They also participate in the sensory functions of the fingers, providing a harsh contrast to the softer skin of the fingertips. With age, nails can begin to deteriorate or develop a disease that leads to the formation of thick nails. Although there are many potential causes of thick toenails, a fungal infection is the most likely cause of toenails.
Other pathologies, such as psoriasis or diabetes, can also be the cause of the formation of thick nails. The exact cause of thick nails will determine what treatment should be followed to correct this condition.

Symptoms and appearance

At first, thick nails can go unnoticed. But as the nails become noticeably thicker, she may notice more symptoms, including the following:

weak, easily broken nails
a bad smell coming from the nail
nails are easily lifted from the nail bed or do not appear to be fully attached to the nail bed
it is difficult to cut or trim them
the nail splits or cracks easily
dirt or other debris gets under the nails
pain or discomfort

As the toenails thicken, they may appear rough, grooved or scaly on the surface. Nails can also take on a yellow, green or brown hue.

Causes and risk factors

There are several reasons why nails can become thicker. Most of them are related to infections or other medical problems related to thickened nails.

Some of the most common reasons are listed below:

– Fungal and yeast infections

Fungal and yeast infections primarily affect toenails rather than fingernails. A type of fungal infection called onychomycosis is one of the most common causes of thick nails. Fungal infections often develop in toenails because they thrive in warm, moist environments. They spread easily and can grow quickly, causing many of the symptoms described above. Some people are more prone to yeast infections than others. Here are some of the main causes of fungal toenail infections:

constant exposure to wet areas
binding shoes
damage to the nail or next to the nail

Also, certain health conditions can increase the risk of fungal nail infections, such as:

athlete’s foot
immune defects
circulatory problems

To prevent fungal infections, avoid going barefoot in public places, especially changing rooms and showers. It is also important to keep the shoes dry.
Doctors generally do not consider fungal nail infections to be serious. These infections can often get better with treatment. It is not always possible for the nail to completely regain its former appearance. However, treating the fungal infection can help the person reduce their discomfort and improve the appearance of the nail.

– Sore

Toenails can become thicker as a result of sudden or repeated trauma or injury. It most often happens to people who play sports or exercise, such as soccer players, runners, and dancers. It can also affect people who wear ill-fitting shoes. Thick nails due to injury are often mistaken for fungal infections.
Seeing a doctor for a nail injury can help the nail grow back more normally. If treatment is effective, improvement is likely to be slow. It takes months for the new nail growth to completely replace the length of the nail.

– Yellow nail syndrome

This less common cause of thick nails affects both fingernails and toenails. The nails become yellow, curved and thickened. A person with yellow nail syndrome usually has breathing problems and swelling in the arms and legs. This is due to an accumulation of fluid around the lungs and in the limbs. Although doctors do not know the exact cause of yellow nail syndrome, some believe there may be a genetic link. This condition may also be associated with certain cancers and immune disorders. There is currently no treatment for yellow nail syndrome, and treatments for affected nails have limited effectiveness.

– Psoriasis

Psoriasis is an autoimmune disease that typically causes red, scaly patches on the skin. Nail psoriasis often accompanies this disease and affects both fingernails and toenails. In addition to thickening, psoriasis can also cause nail changes, such as

detachment of the nail bed
People with nail psoriasis may experience symptoms that come and go at intervals. Treatment can reduce inflammation and improve the condition of the nail over time, but healing is usually a slow process.

– Paronychia

Paronychia is an inflammation that causes redness and swelling of the skin around the nail. Inflammation in the nail area over a long period is called chronic paronychia. It can be caused by infections or exposure to irritants such as cleaning solutions. Over time, fingernails and toenails can become thick. A person may notice that layers of the nail begin to peel off. People can develop paronychia by frequently sucking their fingers, doing the dishes, and cutting nails or cuticles too much.

Several occupations also have an increased risk of developing thick nails due to paronychia. These jobs are:

the bartenders
the whitewashers
the cleaning assistants

The condition usually affects several fingers or toes. Chronic paronychia can be managed by:

avoid contact with irritants
treat inflammation
allows the nail’s natural barrier to heal over time.

– Aging

Often, with age, toenails begin to thicken. Although this condition is most common on toenails, it is also possible for fingernails to thicken.
Health professionals believe that nails thicken with age due to changes in blood circulation or long-term UV exposure. Thick nails and ridges that form on the nail due to aging cannot be treated. But a person can polish them lightly to soften their appearance.

Other reasons

Rare causes of thickened nails include the following:

congenital pachyonychia, a rare genetic disease
pityriasis rubra pilaris, a rare group of inflammatory skin diseases
severe scabies infection.


Thick nails are often a symptom of another infection or disorder. In most cases, thick nails are unlikely to cause further complications. But if left untreated, they can continue to get worse, causing pain and making it uncomfortable to wear shoes. Very thick nails can lead to loss of dexterity. Seeking a medical diagnosis for thick toenails can help prevent other complications that may arise. For example, a person may need treatment for an underlying condition that affects nail health, such as diabetes.


It is possible to prevent some causes of thick nails. Thick nails are less likely to occur if hands and feet are kept clean and dry and if nails are trimmed short. Nail infections can enter the nail through cuts or cracks in the surrounding skin. People can avoid some nail infections by keeping hands and feet hydrated to prevent cracking and by treating wounds or other skin problems.

To prevent thick nails, a person should avoid the following situations:

work in wet environments without gloves
share nail clippers
share towels
walking barefoot in public places such as changing rooms or showers.
People should always wear gloves when working in a damp area.

Here are more prevention tips

wear well-fitting shoes

keep socks and shoes dry


Thick nails do not always require treatment. In cases where aging causes the nails to thicken, treatment will likely be as simple as buffing rough surfaces to smooth them out. In other cases, a doctor must prescribe treatment. The goal may be to improve the condition of the nail or to prevent it from getting worse.

Treatment options for thick nails include:

prescription creams or ointments
oral medication
laser therapy or light therapy
surgery to remove the nail and let it grow back.
The doctor will choose the appropriate treatments depending on the cause of the thickening of the nails.


In some cases, the cause of thick nails can be benign, such as aging. In other cases, the person will need treatment to treat the underlying condition. Thick nails can sometimes be a sign of other health problems. It is important to seek medical attention and treatment when thickening or discoloration of the nails is observed. If left untreated, thick nails can get worse over time. By avoiding irritation and infection of the nail area, a person can often prevent thickening of the nails.

* Presse Santé strives to convey health knowledge in a language that is accessible to everyone. IN NO CIRCUMSTANCES can the information provided replace the advice of a healthcare professional.