Onychauxis is a condition that affects the nails of the fingers and toes. The name of the disease derives from the Greek and comes from the terms ‘onyx’ for fingernail and ‘auxano’ for reproduction. Onychauxis is either present in the affected person from birth or is acquired later in life through various influences.


What is Onychauxis?

Onychauxis is a pathological abnormality in the growth and appearance of the nails of the fingers and toes. Some patients have the disease from birth. In other cases, onychauxis develops later in life, with certain risk factors favoring onychauxis development. See acronymmonster for Definition of Microtia in English.

It is typical of onychauxis that the fingernails and toenails are more or less clearly thickened. However, the nails are not deformed, but mostly grow in the same shape as healthy nails. The medical scientific literature rarely uses the term disease. Instead, there are more case descriptions of onychogryphosis and onychogryposis.

In both cases, the nails of the toes and fingers are affected not only by significant thickening, but also by deformation. Onychauxis occurs, for example, in people who suffer from what is known as acromegaly or psoriasis. Wearing shoes that are too tight or too small for a longer period of time also increases the risk of affected people developing acquired onychauxis.

In addition, onychauxis sometimes occurs in connection with certain disease syndromes. Pachyonychia congenita, for example, is an autosomal recessive inherited dysplasia of the nails. There are genetic mutations in the FZD6 gene.


Various factors favor the pathogenesis of onychauxis. The acquired form of the disease occurs, for example, as a result of traumatic effects on the nails of the fingers and toes. This is the case, for example, with injuries to the nail. Prolonged, excessive exposure to pressure on the nail also increases the risk of developing onychauxis.

In addition, frostbite of the fingers or toes can trigger onychauxis. The thickening of the nails is particularly common as a result of shoes that are too small and press on the toenails. In addition, onychauxis frequently occurs in association with certain diseases and syndromes.

For example, onychauxis is more frequently associated with Darier’s disease, pityriasis rubra pilaris, acromegaly and psoriasis. In principle, acquired onychauxis develops in numerous cases only on individual nails of the fingers or toes, depending on where the traumatic impact took place.

Symptoms, Ailments & Signs

Onychauxis manifests itself through characteristic symptoms and signs. The affected nails on toes and fingers are noticeably thickened. In addition, they often have a yellowish color. Onychauxis is often confused with onychomycosis and psoriasis.

Although the diseased nail thickens significantly and thus increases in height and volume, stability does not always increase to the same extent. When cutting nails affected by onychauxis, they often crack, break, or crumble. The surface of the nail sometimes appears pitted and porous. In other cases, cutting the diseased nails is hardly possible because the thickening is too great or the consistency is too firm.

Diagnosis & course of disease

If people show the typical signs and symptoms of onychauxis, a doctor should be informed about the symptoms. The general practitioner is initially a suitable contact person who carries out an initial anamnesis and small visual examinations with the patient. After a preliminary assessment of the diseased nails on the toes and fingers, the doctor may refer the person to a podiatrist.

In some cases, however, the family doctor himself initiates the further treatment steps. The diagnosis of onychauxis begins with a detailed discussion with the patient. In addition to the individual symptoms, the doctor attaches great importance to learning as much as possible about the background and possible factors behind the thickening of the nail.

In the case of acquired onychauxis, traumatic effects on the nail such as injuries are particularly relevant. Long-term stress such as wearing shoes that are too small also indicate onychauxis. In the congenital form of onychauxis, certain disease syndromes indicate the disease, for example Darier’s disease. If a person suffers from certain chronic and congenital diseases, they are predestined to develop onychauxis.


A causal treatment of onychauxis is not always possible. In these cases, the patient must be prepared to be permanently dependent on the help of a trained podiatrist, who usually uses special tools to flatten the thickened nails. This treatment must be repeated at regular intervals.

In the case of acquired onychauxis, a number of behavioral adjustments can also be made to the patient. In most cases, tight or pointed shoes may no longer be worn, as these constantly press on the nail and cause or at least promote the thickening caused by the disease. Some patients are no longer allowed to wear standard shoes at all, but have to get used to special orthopedic shoes.

Those affected must also reckon with additional complications if the thickened nails are particularly strong or very porous. If the stability develops proportionally to the thickness of the nail, it can often no longer be cut or filed with standard pedicure instruments. Those affected are then dependent on the help of trained podiatrists.

If particularly strong nails grow in, this is extremely painful for the patient. If the nails become particularly porous, there is a risk that those affected will slip off when cutting the nails and injure the nail bed or the surrounding tissue. The cuts can be very painful and become infected.

When should you go to the doctor?

Any changes or abnormalities in the nails should be observed. If the irregularities grow out of their own accord and there are no symptoms afterwards, a doctor is usually not needed. If the problems persist or the symptoms spread, you need to see a doctor for a check-up.

Discoloration of the nails on the hands or toes is considered unusual and should be evaluated medically. If the nails become unstable, quick injuries or damage to the nail structure occur, the instructions should be discussed with a doctor. These are often warning signs of the organism for existing diseases that have to be clarified.

Thickening or brittle nails are further signs of an existing irregularity. They should be examined so that a diagnosis can be made. If the person concerned suffers from psychological problems due to the optical changes, a doctor is also required. Being depressed, mood swings, or withdrawing from social life is cause for concern. Strong feelings of shame or disgust should be discussed with a doctor. For many people, biting their nails indicates an inner imbalance. Mental stress or emotional irregularities often contribute to a deterioration in the overall condition. In addition, the risk of secondary diseases or other complaints is increased.

Treatment & Therapy

A causal treatment of onychauxis is often not practical. Instead, the focus is on the cosmetic treatment of the thickened nails. Such technical treatment measures are usually carried out by a trained podiatrist. The plate of the diseased nail is flattened with the help of special files. Sometimes special shoe shapes are recommended so that the pressure on the nail is reduced.

Outlook & Forecast

Onychauxis offers a good prognosis. The disease can be treated well and does not result in any health problems for the patient. If the condition is treated early, the individual symptoms can be reliably alleviated. Life expectancy is not reduced by onychauxis. However, well-being can sometimes be severely restricted, especially with physical activity.

In the case of chronic diseases, a malposition often develops as well. This can result in psychological and physical complaints that are a heavy burden for the patient. Consequential diseases such as joint wear or circulatory disorders, which occur primarily in advanced onychauxis, are particularly problematic.

The prognosis for onychauxis is usually made by the competent podiatrist. To do this, the severity of the disease must be assessed, taking into account a number of factors such as the type and severity of the deformity and the causative disease. The prognosis can usually be made after just a few treatment appointments and does not have to be changed if the course is expected. Onychauxis can always return unless the causes of the condition are addressed.


Prevention of onychauxis is only possible in the acquired form of the disease. People avoid wearing shoes that are too tight for long periods of time and avoid trauma to the nails due to injuries. However, prevention due to unforeseen accidents is not always successful.


In most cases, those affected with onychauxis have only limited follow-up measures available because it is a rare disease. If the disease has been present since birth, it can usually not be completely cured. Therefore, if the person concerned wants to have children, they should have a genetic examination and counseling carried out in order to prevent the disease from reoccurring.

As a rule, it cannot heal on its own. Most patients with this disease depend on various cosmetic procedures that can alleviate and limit the symptoms. These may have to be repeated more often, so that a complete limitation of the disease is not possible.

Contact with other patients with the disease can also be very useful in the case of onychauxis, as this leads to an exchange of information, which can make everyday life easier for those affected. Likewise, the nails of the affected person should not be put under too much strain, so as not to aggravate the symptoms. Further aftercare measures are not available to those affected with this disease and are usually not necessary. The onychauxis does not reduce the life expectancy of the affected person.

You can do that yourself

Onychauxis can occur in connection with various diseases and injuries. The treatment methods are correspondingly diverse. In general, toenail deformity does not require treatment unless it causes pain, discomfort, or other discomfort. It is usually sufficient to wear suitable shoes and regularly check the affected area for changes.

If swelling occurs or another problem occurs, a doctor’s visit is recommended. Before that, you can try to correct the change in the toenail with foot baths or massages. If these measures have no effect, the family doctor should be consulted. Onychauxis can be fixed by having a podiatrist grind down the nail plate. With the help of the right foot care products, those affected can often do this themselves. However, appropriate podiatry training should be available to prevent injuries.

Lastly, an onychauxis must be seen as a warning sign. It is important to identify the trigger and prevent it from happening again. A small onychauxis usually causes no symptoms and does not need to be treated. If the thickened nail cannot be cut itself because it is too hard, a podiatrist or a professional podiatrist should be consulted.