Lichen nitidus is one of the rare chronic skin diseases of unclear genesis and mechanism of development. Mostly boys of preschool age are ill. The primary element of the rash is considered to be a granuloma – a dense nodule, the size of a pinhead, resembling a focus of productive inflammation in tuberculosis, rheumatism, syphilis, sarcoidosis and other diseases. It has no tendency to merge, spread. Localization of rashes is typical: the head of the penis, lower abdomen, elbows, knees. Dermatosis almost never occurs on the skin of the face, scalp, palms and soles. There are no subjective feelings. There is no special diagnosis. Treatment is symptomatic.
General information
Lichen nitidus is a rare chronic benign dermatosis. He has been known as an independent nosological unit since 1907, when his clinical picture was described in detail on the pages of the dermatological bulletin by Dr. Pinkus. Since then, chronic lichen with monomorphic rashes in the form of nodules on the surface of the skin has received a second name – Pinkus lichen. This small-nodular dermatosis, most likely, of an infectious-allergic nature, with a typical localization of rashes, is characteristic of boys 3-9 years old. Hereditary predisposition has not been revealed, there is no seasonality. The ailment does not violate the quality of life, it causes inconvenience of a purely cosmetic nature.
Currently, it is considered that lichen nitidus is one of the varieties of red lichen planus or a specific trace reaction to the presence of tuberculosis bacilli in the child’s body.
Causes
Lichen nitidus is a chronic skin disease of a persistent course, in which the primary elements, having just appeared, immediately tend to self-involution or reverse development. The causes and mechanism of development of the disease have not yet been studied. Modern practical dermatology focuses on the infectious and allergic nature of the disease. The infectious component of pathology is indicated by the mandatory presence of a focal infection during the examination of the child and a positive result from antibiotic therapy. In favor of allergic genesis, the fairly frequent presence of atopic dermatitis in the patient’s history is evidenced, which reliably confirms the sensitization mood of the body.
It is not accepted to classify lichen nitidus in connection with the monomorphism of the clinic in dermatology, but its rare variants should be mentioned. One of them is post–traumatic lichen nitidus, when the primary elements appear directly at the site of injury. Rare also include a generalized form of the disease, which occurs against the background of a sharp decrease in immunity after suffering stress, hypothermia, severe illness. The primary elements of rare forms of lichen nitidus can be hemorrhagic, vesicular, perforating, merging, palmar-plantar. However, this is more of a casuistry than a rule.
Symptoms
The classic clinic of brilliant lichen resembles vulgar red lichen planus in children. The primary element is an oval, shiny, pearlescent flat nodule, the size of a millet grain. The primary elements are located very close to each other, but they never merge, having clearly defined boundaries. The color of the rash is from flesh to bright pink, without peeling. The rash is localized in the lower abdomen, in the genital area, on the lateral surfaces of the arms and legs, in the elbow and knee bends, on the forearms. Much less often, the rash appears on their internal surfaces and on the mucous membranes of the oral cavity.
The general condition of the child is not disturbed. The disease is chronic. Rashes exist on the skin from several weeks to several years, and then spontaneously regress – independently, without any visible causes, traces and consequences. That is why lichen nitidus is classified as a dermatosis with a benign course.
Diagnostics
The clinical diagnosis does not cause difficulties for a dermatologist. In order to exclude focal foci of infection, it is necessary to examine the child according to the clinical minimum: blood test, fluorography. In the case of rare forms of the disease, specific skin tests and histological examination are used. There is no typical morphological picture. Histologically, there are two types of structure of the primary element: granuloma-tubercle and granuloma of an inflammatory nature of non-tuberculosis origin. Both are located in the upper layers of the dermis, have sharply defined borders, consist of lymphocytes, phagocytes, blast cells. In the central part of the “newborn” granuloma there is a blood vessel, in the tubercles of the “retirement age” there is necrosis.
Differential diagnosis is of greater importance. Lichen nitidus should be distinguished from the banal “goose skin”, or follicular hyperkeratosis – by the nature of the nodules and the prevalence of the process (“goose skin” tends to totally capture the skin, while its “nodules” are nothing more than compacted hair follicles); from red flat lichen – by color and size “millet grains” (with red lichen planus, the primary elements are larger and brighter, can transform into plaques).
You can differentiate lichen nitidus from spiny lichen by the “grater symptom” (if you run your hand over the skin with rashes of spiny lichen, which have a “spike” of hyperkeratosis at the top of the nodule, you will feel that you have passed your hand over the grater). From lichenoid tuberculosis of the skin and lichenoid syphilis, lichen nitidus is reliably differentiated only with the help of histology results and a complete clinical examination of the patient. To differentiate lichen nitidus from follicular mucinosis, the age of the patient is sufficient (mucinosis affects not children, but mature men). In addition, follicular mucinosis occurs on the scalp, in the eyebrows and neck, and lichen nitidus does not.
Lichen nitidus treatment
Lichen nitidus has a benign course, does not cause subjective sensations, is prone to self-resolution, therefore, the treatment of dermatosis is purely symptomatic: the foci of chronic infection are sanitized, functional disorders are corrected. First of all, they strengthen the immune system, the nervous system. To do this, courses of vitamin therapy (A, B1, C, D2, multivitamins), immunostimulating drugs (echinacea juice, eleutherococcus extract, ginseng tincture), iron preparations, physiotherapy (UVO) are used. Coniferous baths or bran baths are shown. Externally, 1-2% resorcinol, salicylic, sulfur ointments are used. In the case of resistance, hormonal ointments with baby cream are shown in a ratio of 1:1. Spa treatment (Matsesta) gives good results.
Prognosis and prevention
The prognosis, taking into account the self-resolution of the process, is favorable. There is no special prevention. However, hardening the child, strengthening his immunity, playing sports, a rational daily routine, the absence of inadequate physical and mental loads, coupled with annual preventive examinations at the pediatrician, is a guarantee of the absence of meetings with brilliant lichen.