Ichthyosis is a hereditary skin disease that occurs according to the type of dermatosis. It is characterized by a diffuse keratinization disorder and manifests itself in the form of scales on the skin that resemble fish scales. The main cause of ichthyosis is a genetic mutation, the inherited biochemistry of which has not yet been deciphered. Protein metabolism disorders, when amino acids accumulate in the blood and fat metabolism disorders, which are manifested by an increased cholesterol content, are the main manifestation of a gene mutation that leads to ichthyosis.
Ichthyosis is a hereditary skin disease that occurs according to the type of dermatosis. It is characterized by a diffuse keratinization disorder and manifests itself in the form of scales on the skin that resemble fish scales.
The main cause of ichthyosis is a genetic mutation, the inherited biochemistry of which has not yet been deciphered. Disorders of protein metabolism, when amino acids accumulate in the blood and disorders of fat metabolism, which are manifested by an increased cholesterol content, are the main manifestation of a gene mutation that leads to ichthyosis.
All metabolic processes decrease, the thermoregulation of the body is disrupted, and the activity of enzymes in the oxidative processes of skin respiration, on the contrary, increases. In patients with a gene mutation that is the cause of ichthyosis, a decrease in the activity of the thyroid gland, adrenal glands and gonads gradually increases or immediately appears, and the deficiency of humoral and cellular immunity increases. Violation of the absorption of vitamin A, together with reduced functions of the sweat glands, leads to a violation of keratinization of the skin towards hyperkeratosis, since there is an excessive production of keratin with an altered structure, which, together with slowing down the process of rejection of the keratinized layer of the epidermis, causes manifestations of ichthyosis. With ichthyosis, amino acid complexes accumulate between the scales, which have a cementing effect, so the scales are tightly interconnected, and their separation from the body is sharply painful.
Ordinary or vulgar ichthyosis manifests itself at the age of up to three years, but it is usually diagnosed before the third month of life. This is the most common form of ichthyosis inherited by autosomal dominant type. At first, the skin becomes dry and rough, then it is covered with small whitish or gray-black scales tightly adjacent to each other. With ichthyosis, the area of the elbow bends, popliteal pits, the area of the armpits and the inguinal zone are not affected.
Mucoid peeling appears on the palms, the skin pattern becomes pronounced. The severity of the course of ichthyosis depends on how deep the gene mutation is, an abortive course is possible, when the only manifestation of ichthyosis is dryness and slight peeling of the skin on the extensor surfaces.
With ichthyosis, hair, teeth and nails undergo dystrophic changes. Dry brittle hair is characteristic, nails break off and delaminate, multiple caries joins. Quite often, ichthyosis is accompanied by eye damage – chronic conjunctivitis and retinitis. Patients with ichthyosis have a hereditary predisposition to myopia, which begins to manifest itself in childhood. Since immunity is reduced, allergic diseases and purulent infections are permanent. Later, disorders in the work of internal organs are joined, most often cardiovascular insufficiency and liver diseases are noted.
Recessive ichthyosis occurs only in males, although it is inherited on the X chromosome and differs in that the cause of the disease is a defect of placental enzymes. Clinical manifestations appear in the second week of life, less often immediately after birth. Horny layers of skin look like large dense scales of black-brown color and resemble shields. The skin between the scales is covered with cracks, because it looks like the skin of a crocodile or snake. Children with recessive ichthyosis often have mental retardation, abnormalities in the structure of the skeleton, epilepsy. Juvenile cataracts and hypogonadism occur in 10-12% of cases.
Congenital ichthyosis develops in utero at 4-5 months of pregnancy. At birth, the baby’s skin is covered with thick horn shields of gray-black color. With congenital ichthyosis, the scales can reach up to 1 cm in thickness, the scales have different shapes, smooth or jagged, the skin between them is covered with furrows and cracks. Due to the dense, well-connected scales, the baby’s mouth opening is either stretched or sharply narrowed so that the feeding probe barely passes. The ear holes are deformed and filled with horny scales, the eyelids are turned out due to stretching. Almost all infants have skeletal abnormalities – clubfoot, myopia, many children with a congenital form of ichthyosis have interdigital bridges on the feet and palms, sometimes there are no nails. Pregnancy is more often premature, the percentage of stillbirths is quite high. Since there are anomalies incompatible with life, most children with a congenital form of ichthyosis die in the first days of life.
Epidermolytic ichthyosis is a form of congenital ichthyosis. The baby’s skin is bright red, as if scalded with boiling water. Nikolsky’s syndrome is positive as in the case of pemphigus of newborns – with a slight touch, the rejection of the epidermis scales is observed. The skin on the palms and soles is white, significantly thickened. In some cases, with the epidermolytic form of ichthyosis, there may be hemorrhages in the skin and mucous membranes. This is an unfavorable sign, if hemorrhages join, then children most often die. With milder clinical manifestations of ichthyosis, the bubbles become smaller over time, but throughout life the disease recurs in the form of outbreaks, while during the recurrence of ichthyosis, the temperature often rises to high levels. By the fourth year of life, horny layers appear on certain parts of the body in the form of thick dirty-gray scales, which are localized mainly in the places of natural skin folds.
Often there are defects in the nervous, endocrine and other body systems, many children with congenital ichthyosis are later diagnosed with oligophrenia, spastic paralysis, the cause of which is the accumulation of phytanic acid in the tissues. Polyneuropathies, anemia, infantilism complicate the course of ichthyosis. The mortality rate is very high due to concomitant complications and associated diseases.
In most cases, clinical manifestations are sufficient to diagnose ichthyosis. In congenital forms, it needs to be differentiated with erythermoderma and other diseases. Histological examination of the skin confirms the diagnosis. Methods of gene diagnostics have been developed.
Treatment of ichthyosis, depending on the severity, is carried out by a dermatologist on an outpatient basis or in a hospital. Vitamins A, E, B, vitamin C and nicotinic acid are prescribed in high doses for long multiple courses. Drugs that have a lipotropic effect soften the scales. These are preparations containing lipamide and vitamin U. Plasma transfusions, gamma globulin, preparations containing iron and calcium, as well as aloe extract are shown to stimulate immunity. If there are lesions of the thyroid gland with the development of hypothyroidism, then thyroidin is indicated, with hypofunction of the pancreas – insulin.
In severe cases and with congenital ichthyosis, hormone therapy is immediately prescribed, if there is an eversion of the eyelids, then an oil solution of retinol acetate is instilled into the eyes. After normalization of the condition, the dose of hormonal drugs is slowly reduced to complete withdrawal. During remissions, blood tests are periodically performed to monitor the general condition of the patient and prevent the development of complications. Nursing mothers are shown to take all vitamins, as well as children with ichthyosis.
Local therapy consists in taking general baths with a solution of potassium permanganate and lubricating the skin with baby cream with vitamin A added to it. Adult patients with ichthyosis are shown salt and starch, general or local baths, depending on the localization of the process. Vitamin A, sodium chloride and urea are added to the water.
UV irradiation in suberythemic doses, thalassotherapy and heliotherapy, resorts with sulfide and carbon dioxide baths stimulate metabolic processes in the dermis. Silt and peat mud are recommended already at the stage of resolving the recurrence of ichthyosis and as a preventive measure. Aromatic retinoids, due to the fact that they restore the work of dermal cells and normalize metabolic processes, have recently become widespread in the treatment of ichthyosis.
Prognosis and prevention
The prognosis of ichthyosis is always unfavorable, since even with mild forms of the disease, the addition of systemic pathologies and the progression of metabolic diseases lead to complications. The main prevention of ichthyosis is counseling before pregnancy in order to determine the degree of genetic risk. If fetal ichthyosis is detected during the analysis of amniotic fluid, then termination of pregnancy is recommended. Couples whose risk of having a child with ichthyosis is quite high, it is better to refrain from pregnancy in favor of adopting orphaned children.