Neurodermitis

Neurodermitis is a chronic recurrent inflammatory skin disease manifested by intensive itching, papular eruptions and marked lichenification.

Circumscribed (neurodermitis circumscripta) and diffuse (neurodermitis diffusa) are distinguished.

Etiology and pathogenesis. Neurodermitis results mainly from the effect of endogenic factors, such as disturbed activity of the nervous system, endocrine glands and internal organs, metabolic disorders, and under the effect of unfavourable environmental factors. Neurotic disorders of various degrees are observed: increased excitation or restraint, rapid exhaustion, asthenia, emotional lability, insomnia, etc. All this sustains the tormenting and persistent itching, which is the dominant symptom of neurodermitis.

Disturbed functioning of the higher parts of the central nervous system may be of primary character and play an etiological role in the origin of neurodermitis. In some patients they are of secondary character, appearing as a consequence of a persistent skin disease, protracted and severe itching and insomnia. A vicious circle is thus formed: the severe course of neurodermitis and the tormenting itching sustain and intensify the neurotic disorders, whereas the neurotic disorders aggravate the course of neurodermitis.

The causes of the origin of neurodermitis discussed from the standpoint of functional disorders in the central nervous system in the first place, and then in the vegetative and endocrine systems, the role of allergic states of the body and metabolic disorders in various internal organs do not contradict but even supplement one another. The frequently encountered combination of functional disorders of the nervous system with endocrine disturbances (disorders of the hypophyseal-adrenal system and less frequently of the thyroid and gonads) provide grounds for stating that neuroendocrine disorders play the leading role in the pathogenesis of neurodermitis.

Chronic catarrhal inflammation of the mucous membrane of the distal part of the rectum and anal canal plays an important role in the pathogenesis of localized neurodermitis and itching in the region of the anus.

The principal role in the pathogenesis of localized neurodermitis of the external genitals may be attributed to neurosexual disorders, various inflammatory processes in the region of the genitals, hormonal gonadal dysfunction, and chronic diseases of the sexual sphere (adnexitis and endometritis in females, prostatitis in males, etc.).

Infiltration with lichenification of the skin against the background of erythema (of non-acute inflammatory character) predominate in the clinical picture of diffuse neurodermitis. The foci of affection are mostly localized on the face, neck, flexor surfaces of the limbs (cubital and popliteal fossae), in the region of the genitals, medial surfaces of the thighs and on other body areas. Epidermodermal papules are the commonly encountered primary morphological lesions. They are often distinguished with difficulty from the healthy skin in colour and in places they coalesce to form areas of papular infiltration. The skin in the foci of affection is often hyperpigmented and dry and numerous excoriations and microfurfuraceous scales are seen. Linear fissures are often found in the natural folds against the background of infiltration. Affection of the skin manifested by severe itching and a monomorphous eruption, in many cases neurotic disorders of this or that degree, white dermatographia constitute the typical clinical picture of neurodermitis. Hypocorticism in patients with neurodermitis is manifested by hyperpigmentation, often by hypotonia, adynamia, allergic reactions, reduced secretion of gastric juice, hypoglycemia, a certain reduction in urine excretion, loss of body weight, and increased fatigability.

Diffuse neurodermitis is usually seasonal; the patient's condition usually improves in summer and deteriorates in winter. In some cases the process is combined with bronchial asthma, hay fever, vasomotor rhinitis, and other allergic diseases. Impetiginization and eczematization of the process are possible (development of vesiculation, short-term weeping, erythema of an acute inflammatory character).

From the pathohistological aspect, diffuse neurodermitis is characterized by para- and hyperkeratosis, mild acanthosis, intra- and intercellular oedema, oedema of the papilli, and a round-cell (lymphohistiocytic) infiltrate found prevalently around mildly dilated vessels in the dermis.

Localized neurodermitis develops on a circumscribed skin area but is agonizing for the patient because of very severe itching, which usually appears in the evening or at night. The favoured localization is the posterior and lateral surfaces of the neck, the anal-genital region (in these patients the skin of the medial surface of the thighs is often involved in the process), the intergluteal folds, and the flexor surfaces of the large joints. At first the skin on the localized area remains unchanged. With time, however, papular lesions of a dense consistency and covered with furfuraceous scales in places appear in combination with itching and scratching. After that individual, predominantly the lichenoid, papules coalesce and form flat plaques of various size (continuous papular infiltration) pale-pink to brownish-red in colour with oval or rounded contours. The skin pattern gradually becomes markedly exaggerated, i.e. lichenification develops. The skin turns shagreen-like. In typical cases three zones may be distinguished at the peak of the process in localized neurodermitis: a central zone with lichenification, a middle zone with isolated shiny, often with a smooth surface, pale-pink papules, and a peripheral zone with hyperpigmentation. Excoriations (fresh or covered with hemorrhagic crusts) are often seen against the background of erythema, which is of a non-inflammatory character. In exacerbation of the process disseminated pruriginous lesions are sometimes seen besides the grouped coalesced lichenoid papules, scaling intensifies and erythema becomes brighter. The disease follows a protracted course measured in years.

Histopathology. The histological picture is marked by parakeratosis (less frequently by hyperkeratosis), acanthosis, infiltration of the papillary and frequently of the reticular dermal layers.

Treatment. Sedative therapy and psychotherapy in combination with low, gradually decreasing doses of anti-inflammatory and hyposensitizing corticosteroid hormones (Urbasone, Dexamethasone) are recommended for patients with a diffuse process. These hormones are prescribed in a persistent course of the disease, severe itching, and a tendency to dissemination of the foci of affection when the process responds poorly to other methods of treatment. The activity of the central nervous system is normalized and neurotic reactions reduced by means of preparations of bromide and valeriana, neuroplegics and antihistaminic antipruritic agents (Tavegil, Phencarol, Klaritin, Suprastin, etc.). Vitamins of the B complex, and vitamins PP and A are prescribed. Sulphurated hydrogen and radon baths, ultraviolet irradiation and heliotherapy (photochemotherapy) are the recommended physiotherapeutic measures. Baths with bur-marigold, oak bark or chamomile decoction are advisable. After the bath the dry skin areas are smeared with nutrient cream (Lanolini, 01. Olivarum, Aq. destill. aa 30.0) or olive oil. Keratoplastic ointments with naphthalan, tar, sulphur, ichthammol, ASD solution are applied.

Ointments containing corticosteroids (Synalar, Locacorten, Flucinar, Ftorokort, etc.) are applied to the affected areas. Aniline dyes, Castellani's paint and Oxycort, Geocorton, Locacorten N, Locacorten-Vioform ointments are used for external therapy of secondary infection. Patients with localized neurodermitis, like those with diffuse and disseminated processes, are given sedatives and antihistaminic agents, a diet with restriction of spicy and smoked foods and exclusion of salt foodstuffs. Alcoholic beverages and food which intensifies itching and the inflammatory process of the skin are not allowed. Injections of hydrocortisone emulsion around the foci are advisable in pronounced lichenification and infiltration of the foci. A long stay in the south in summer is recommended for the prevention of recurrences and prolongation of the achieved remission, as well as a rational hygienic regimen, treatment of foci of chronic infection, and removal of food, drug and household allergens (animals' fur, everyday household chemicals, household dust, etc.).