Xanthomatosis is a metabolic disease in which deposits of lipids, mainly cholesterol and cholestanol (xanthomas), form on the surface of the skin and in some other tissues. Symptoms of this condition are yellowish painless plaques and growths on the skin of the face, lower eyelids (xanthelasm), limbs and trunk without signs of inflammation. Diagnosis of xanthomatosis is carried out according to the results of examination of the skin, as well as the study of the main indicators of lipid metabolism (cholesterol and lipoprotein levels in the blood). Treatment is divided into general – correction of lipid metabolism – and local, in which xanthus is removed surgically or by means of medical cosmetology.
Xanthomatosis is a multiple deposition of lipoid substances in the skin (in some cases – in bones, dura mater, tendons), which are caused by hyperlipidemia. One of the first researchers who was able to correctly describe and characterize this dermatological condition back in 1835 was the French physician P. Rayet. Xanthomatosis of the skin is only part of the manifestations of impaired lipid metabolism, in addition, patients may also experience xanthelasm, atherosclerosis, corneal lipoid arch and even heart defects caused by the deposition of lipids on the valves. This condition is not common, it can be caused by both primary (genetic) disorders and acquired disorders of fat metabolism. In some cases, xanthomatosis is caused by age-related changes. Depending on the type and nature of lipid metabolism disorders, this skin disease can manifest itself at different ages – from childhood and adolescence to old age and senile.
The main reason for the development of xanthomatosis is a violation of lipid metabolism with the development of hyperlipidemia – a condition in which the number of different lipoprotein fractions in the blood increases dramatically. Such changes may have a different nature – for example, the primary disorder of fat metabolism has five varieties. Each of them is caused by a malfunction of a certain link in the transport of fats and cholesterol in the body, but they all have approximately the same result – triglycerides and cholesterol in the form of lipoproteins begin to accumulate in the blood, changing its rheological properties.
As a result of complex processes, lipids begin to penetrate into cells and the intercellular space of skin and tendon tissues, forming clusters there that are visually identified as xanthomas. The multiple formation of such clusters on the skin is called xanthomatosis.
In addition to primary or hereditary lipid metabolism disorders leading to hyperlipidemia and xanthomatosis, there are also acquired factors that can increase the level of triglycerides and cholesterol in the blood. These include diabetes mellitus, high intake of fats from food, hypothyroidism, inflammation of the pancreas (pancreatitis), liver damage (severe hepatitis, cirrhosis). In some cases, hyperlipidemia with the development of xanthomatosis occurs in old age as part of a complex of senile changes in the body. As a rule, secondary or acquired forms of xanthomatosis are more common in older or elderly people, while primary ones can develop in both children and adults. The pathogenesis of lipid deposition in the skin in secondary hyperlipidemia has no characteristic differences.
The xanthomas themselves in this condition may have a different appearance, which largely depends on the causes that caused the development of xanthomatosis. So, eruptive xanthomas are isolated, which have first a red, then a yellowish color, but the crimson rim persists around them for a long time. They have clear boundaries and a hemispherical shape. Tuberous xanthomas are characterized by symmetrical formation, have a yellow or brown color and can reach quite large sizes – up to 2-3 centimeters. Flat xanthomas, detected in some types of xanthomatosis, are spots or plaques of yellow color, quite often occur on the palmar surfaces of the brush. Also, tendon xanthomas and xanthelasmas are sometimes isolated into separate types – fatty deposits on the eyelids.
The classification of such a condition as xanthomatosis is inextricably linked with the types of lipid metabolism disorders. The type of such disorders depends on the nature of lipid formations on the skin and in other tissues, the age of their development, the clinical course and a number of other factors. All causes of hyperlipidemia leading to xanthomatosis are divided into two groups – primary and secondary. Primary, in turn, are divided into five varieties, which are characterized by pathologies of different links of lipid metabolism:
- The first type – there is a high level of triglycerides and chylomicrons in the blood. Xanthomatosis in this condition is represented by eruptive xanthomas, which can spread throughout the body, but their predominant localization is the buttocks and flexor surfaces of the elbows and knees. A feature of this form of the disease is the spontaneous disappearance of lipid deposits on the skin with a decrease in the level of triglycerides. Xanthomatosis of this type most often affects children.
- The second type of hyperlipidemia is diagnosed with a simultaneous increase in the level of very low density lipoproteins and cholesterol. This xanthomatosis is mainly characterized by tendon xanthomas ranging in size from a few millimeters to 3-4 centimeters, but flat or tuberous skin deposits of lipids are also possible. Most often, this type of disease affects people over the age of 20.
- The third type – with it, abnormal forms of lipoproteins (beta-lipoproteins) and high levels of triglycerides and cholesterol are observed in the blood. Xanthomatosis in this hyperlipoproteidemia is characterized by the development of flat xanthomas on the palms and upper extremities, tendon and eruptive lipid accumulations are extremely rare. It can be diagnosed in people over 30 years of age.
- The fourth type of hyperlipidemia is characterized by a very high level of triglycerides and very low density lipoproteins against the background of normal cholesterol content. With it, xanthomatosis develops in the form of eruptive and tuberous xanthomas of various localization. The age of manifestation of skin manifestations is 30-40 years.
- The fifth type is diagnosed with a high level of chylomicrons and very low density lipoproteins, as well as a high concentration of triglycerides. The clinical course of xanthomatosis characteristic of this condition is numerous eruptive xanthomas on the background of hepatosplenomegaly, heart defects and pronounced atherosclerosis of coronary vessels.
Thus, if the cause of xanthomatosis is the primary forms of hyperlipidemia, then by the nature of the rash, the age of the patient and other symptoms, you can roughly determine its type. With regard to secondary types of lipid metabolism disorders, such a clear relationship is not revealed. The course of xanthomatosis in this case depends on the severity of the disorder of lipid metabolism and reactivity of the body – it is possible to have both single xanthomas of small size and multiple deposits of fat-like substances throughout the body with a diameter of up to 3-4 centimeters. In the case of secondary xanthomatosis, the symptoms of the underlying pathology that caused the failure of fat metabolism (diabetes mellitus, cirrhosis of the liver, and others) are always added to the clinical picture of the disease.
Usually in dermatology, the diagnosis of such a condition as xanthomatosis does not present any particular difficulties. To do this, a method of examining the patient’s skin, a biochemical blood test or a lipidogram study is used, in controversial cases, a xanth biopsy can be performed for histological examination. When examined by a dermatologist, formations of various shapes, sizes and localization from yellow to brown are revealed, which may be surrounded by a purplish-red border or unchanged skin. They are painless and do not cause the patient any concern, except for an aesthetic defect. Often, the patient’s obesity or, conversely, his excessive thinness (with type I diabetes mellitus) attracts attention.
The lipidogram indicates a high level of various fractions of blood lipids – very low density lipoproteins, chylomicrons, cholesterol or triglycerides. The value of the atherogenicity index increases, which indicates the predominance of harmful lipoprotein fractions in the patient’s blood. The combination of hyperlipidemia and the presence of xanthomas on the skin already clearly indicates in favor of xanthomatosis in the patient. Histological examination of tissues in the lesions determines a large number of foam cells with their predominant localization around blood vessels. When stained with Sudan-3, the cellular inclusions in them turn orange, which indicates their lipid nature. The epidermis in the area of the development of accumulations of fat-like substances with xanthomatosis is little changed, sometimes there is a slight hyperkeratosis.
Treatment and prognosis
The general treatment of xanthomatosis is reduced to a decrease in the level of lipid components in the blood and normalization of fat metabolism. For this purpose, both a low–lipid diet and special anti-atherosclerotic drugs are used – for example, atorvastatin. In cases where hyperlipidemia is caused by another disease, it is necessary to start its treatment – for example, eliminate hypothyroidism, hepatitis, control diabetes mellitus. In some cases, especially at a young age of the patient, and if xanthomatosis was manifested by eruptive xanthomas, after normalization of the lipid level in the blood, the skin manifestations of the disease can disappear independently. In other cases, xanthomas need to be removed by surgical techniques, cryodestruction, laser cauterization or electrocoagulation.
The prognosis of xanthomatosis directly depends on the causes of hyperlipidemia, since some of its forms can manifest not only skin symptoms, but also heart defects, atherosclerosis of coronary and cerebral vessels, hepatomegaly. Xanthomas by themselves do not pose a threat to the patient’s life and can only create cosmetic inconveniences. The prognosis regarding recovery and complete elimination of xanthomatosis in some cases is favorable – while maintaining an optimal level of lipids in the blood, new formations do not appear, and those already formed can be removed by cosmetological methods. However, if hyperlipidemia occurs again for various reasons, then a relapse of the disease is possible.