Under the name hereditary palmoplantar keratosis is used to describe a variety of genetically caused cornification disorders of the palms and soles of the feet. These are diffuse or focal palmoplantar hyperkeratoses. The inherited forms of palmoplantar keratosis are predominantly inherited in an autosomal dominant manner and usually occur in early childhood during the first or second year of life.
The migration of cells from the basement membrane to the surface of the skin takes 28 days. Once there, the horny flakes are peeled off in tiny, barely visible flakes of skin.
The large number of hereditary palmoplantar keratosis (PKK) summarized manifestations of genetically caused hyperkeratoses of the palms and soles of the feet are presented by an equally large variety of symptoms. Acquired ones are also presented with a great variety palmoplantar hyperkeratosis.
They are caused by infections, pollutants, or as a side effect of medication. An important, but not sufficient, distinguishing feature between the two forms is the time at which the disorder occurred. Most genetic forms of hyperkeratosis show the first symptoms in early childhood at one or two years of age.
The acquired forms of the disease only appear after contact with the causative substance, i.e. usually only in adulthood. Hereditary palmoplantar keratoses are often associated with functional impairments in other organs such as eyes or ears or with developmental disorders of the central nervous system.
Some hereditary palmoplantar keratoses are not caused directly, but indirectly by a genetic enzyme defect, such as the Richner-Hanhart syndrome. The syndrome is identical to tyrosinemia type II. Due to a gene mutation, the amino acids tyrosine and phenylalanine are extraordinarily enriched, which among other things triggers the symptoms of palmoplantar hyperkeratosis.
The multitude of manifestations of hereditary palmoplantar keratoses already suggests that there cannot be a single genetic defect causing the disease. In fact, causative mutations have been documented on many different genes that can be on different chromosomes. These are usually genes that encode certain keratin proteins.
Gene mutations lead to incorrect coding of proteins, which is usually associated with a loss of function. In a few cases, such as in Richner-Hanhart syndrome, a gene mutation does not lead to a false coding of a keratin protein, but, for example, to block tyrosine aminotransferase, so that tyrosine and phenylalanine can accumulate extremely in the body. The palmoplantar keratosis caused thereby also fulfills the characteristics of an acquired hyperkeratosis.
In the uppermost layer of human skin, the epidermis or epidermis, fresh skin cells form in a continuous process in the basement membrane that separates the epidermis from the dermis or dermis. These are horny cells that gradually migrate to the surface of the skin with the loss of their cell nucleus and increasing cornification within the epidermis.
The migration of cells from the basement membrane to the surface of the skin takes 28 days. Once there, the horny flakes are peeled off in tiny, barely visible flakes of skin. In the presence of hereditary palmoplantar keratosis, the transformation process of a keratin-containing skin cell into a dead horny platelet is disturbed.
It can also happen that the rate of reproduction of the skin cells in the basement membrane of the epidermis is greatly increased (hyperkeratosis). Most of the manifestations of hereditary palmoplantar keratosis can already be recognized on the basis of specific and typical features of the affected skin areas. The first symptoms usually appear in the form of skin changes and excessively thick calluses.
Indirect indicators for the presence of hereditary, i.e. hereditary PKK are early onset at the age of one to two years and associated functional disorders of other organs or organ systems such as hearing disorders or visual disorders, neurological abnormalities, hyperhidrosis and persistent therapy resistance.
A careful family history, which reveals other cases of palmoplantar keratosis in family members, corroborates the diagnosis that it is an inherited form of the disease. Certain forms of the course also include hair and nails, and as the disease progresses, the affected areas of skin can expand beyond the soles of the feet and palms.
Genetic PKK can show different manifestations in the palms of the hands and on the soles of the feet. For example, the soles of the feet can be affected by diffuse areas, while the palms show accentuated, stripe-like or punctiform cornification disorders.
This disease results in changes and skin complaints that mainly occur on the feet. This leads to a thick cornea. In some cases, this can lead to difficulty walking or pain and thus significantly reduce the patient's quality of life. In most cases, palmoplantar keratosis also causes discomfort to the ears and eyes, and in the worst case, the affected person can go completely blind or lose all of their hearing.
Neurological complaints also occur, which in some cases can also lead to paralysis and other disorders of sensitivity. It is not uncommon for the symptoms to spread to the hair and nails. In these cases, the aesthetic changes also cause patients to suffer from reduced self-esteem and from inferiority complexes.
The treatment is primarily aimed at alleviating the symptoms and does not lead to further complications. As a rule, the disease can be limited by changing one's diet so that the symptoms disappear completely. In some cases, surgical interventions are necessary. Life expectancy is not restricted or reduced by palmoplantar keratosis.
Since this disease does not heal itself and the symptoms usually worsen, treatment must always be carried out by a doctor. A doctor should then be consulted if the patient suffers from a cornification disorder.
This can occur in childhood and affect different regions of the skin. As a rule, the skin becomes very keratinized and flaky. If these symptoms occur without a particular reason and, above all, permanently, a doctor must be consulted.
The dermatologist and general practitioner are initially the right people to talk to. Since the skin complaints can often lead to psychological complaints, psychological treatment is also advisable. Often, disorders of the internal organs or the eyes also indicate the disease and should be examined. Either the ophthalmologist or the internist can determine these disorders.
There is currently no therapy available to cure inherited PKK, so all forms of treatment are limited to relieving symptoms and preventing infections. Exceptions exist in the forms of the disease that can only be traced back indirectly to one or more mutated genes, such as the Richner-Hanhart syndrome mentioned above, in the course of which PKK develops as a concomitant phenomenon.
The keratosis regresses when the person concerned changes their diet to components that are as low in tyrosine as possible without the disease being considered cured. Depending on the manifestation of the disease, treatment consists of mechanical removal of excess horn structures or even surgical intervention. Some variants of the inherited PKK respond to acitretin.
As a derivative of vitamin A, this slows down the formation of corneal cells and is primarily used to treat psoriasis (psoriasis). The drug is not free of side effects. Side effects such as nosebleeds, blurred vision, and dry skin are commonly reported, and prolonged use increases cholesterol levels.
The prognosis of hereditary palmoplantar keratosis depends on the specific disease. It is a group of genetically caused cornification disorders of the skin on the hands and feet. The diseases are all innate.
The first symptoms usually begin in early childhood. Due to their genetic cause, these skin diseases cannot be cured. Only symptomatic therapies are possible, which can bring some relief to the affected patient.
The group of hereditary palmoplantar keratoses includes both diffuse and focal palmoplantar hyperkeratoses. In focal palmoplantar hyperkeratoses, the keratinization processes are delimited, while in diffuse palmoplantar hyperkeratoses larger areas are affected. Most of the time, life expectancy is normal. However, there are also diseases with reduced life expectancy, such as keratoderm with esophageal carcinoma.
The most common form of hereditary palmoplantar keratosis is epidermolytic palmoplantar keratosis. It is characterized by diffuse, but sharply demarcated cornification disorders on the extensor surfaces of the hands and feet with watch-glass nails. Some diseases still show involvement of the ears with the development of inner ear hearing loss in addition to extensive hyperkeratosis.
Examples are the diseases keratoderma hereditarium mutilans or the KID syndrome. Although life expectancy is usually not restricted, the affected patient often suffers from a greatly reduced quality of life. This in turn depends on the success of the cosmetic treatment with keratolytics, which contribute to the dissolution and removal of the excessively formed cornea.
There are no preventive measures to prevent the genetically caused palmoplantar keratosis. If cases of illness within the family become known, there is an increased risk for newborns of developing one of the many possible variants of PKK. A molecular genetic test is only effective if it is known which gene could be affected. Otherwise a genetic test could turn out negative without it being certain that PKK cannot occur.
With this palmoplantar keratosis, the affected person has in most cases no or very few direct measures and options for aftercare available. The person affected should contact a doctor at the first signs and symptoms of the disease so that the symptoms do not continue to worsen. In general, an early detection of the symptoms has a very positive effect on the further course and can also prevent further complications.
In most cases, the symptoms of palmoplantar keratosis can be alleviated and completely limited by a proper diet, so that there is no need to take medication. The doctor can also create a nutrition plan for the parents according to which the child is to be fed. The dry skin should be treated with creams and ointments in this disease so that there are no cracks or other discomfort to the skin.
In most cases, these symptoms disappear again after the treatment, so that no special follow-up measures are necessary. Since palmoplantar keratosis is a hereditary disease, it cannot be completely cured. If you want to have children, a genetic examination and counseling can therefore be useful to prevent the disease from recurring.
Hereditary hereditary palmoplantar keratosis cannot yet be treated causally. Symptoms can be reduced by taking dietary measures.
We recommend a diet that is as low in tyrosine as possible and avoiding coffee, alcohol and cigarettes. In addition, patients should eat a balanced diet rich in vitamins. Exercise and adequate sleep support the healing of the horn structures and increase well-being, which is often reduced, especially in chronic diseases. Finally, in the case of hereditary palmoplantar keratosis, protection and strict personal hygiene apply.
The horn structures can sometimes be reduced with pumice stones and similar aids. So that painful cornifications do not develop in the first place, pressure points should be avoided. Appropriate footwear and clothing significantly reduce the risk of complex horn structures.
Women who have the condition should have their child genetically tested after giving birth. With an early diagnosis, the hereditary disease can be treated well and in the best case does not develop any symptoms. A genetic test is also recommended if the child's father or another family member has PKK.