Skin Pruritus (Pruritus Cutaneus)

Skin pruritus is an independent disease manifested by severe persistent itching and scratches. There is no ultimate opinion to date as to the specificity of the receptors perceiving itching. It is presumed that this is accomplished by the free nerve endings, which perceive pain, or by the endings of non-medullated fibres.

Before making the diagnosis of skin pruritus it is necessary to rule out all diseases of the skin, blood, liver, kidney, pancreas, metabolic disorders, etc., in which itching is among the symptoms of the malady. The diagnosis of pruritus excludes the presence of any primary morphological lesion. As to the secondary morphological lesions, these may be present in the form of excoriations and hemorrhagic (punctate and linear) crusts. In some patients the nails acquire a peculiar 'polished' sharpened appearance as a result of prolonged skin itching. The itching usually occurs in paroxysms in the morning or at night, less frequently during the day. Its intensity varies from mild to very severe, causing partial or total insomnia. Severe itching interferes with the patient's work. According to its extent, itching is subdivided into universal or generalized, and localized. Localized itching is most frequently found in the region of the genitals (vulva, scrotum) and anus. Less frequently it develops on the medial surface of the thighs and legs and on the neck and head. Localized skin pruritus may be caused by helminths (mainly the threadworm), inflammation of the mucous membrane of the vulva, vagina, rectum and anus, vegetoneurosis with local disorders (increased sweating on the itching skin areas) and by neuropsychic, neurosexual, endocrine and other disorders. The cause of generalized itching, in addition to the functional disorders mentioned above, may be metabolic disturbances in elderly and old individuals (senile pruritus), toxicosis (pruritus in pregnancy) and other causes which, however, cannot always be disclosed.

Treatment. Patients with neurotic disorders are given sedatives (bromide, valerian and neuroplegics), antihistaminic agents (Klaritin, Phencarol, Diazolin), hyposensitization therapy (hemodez, calcium preparations, sodium thiosulphate).

Some patients with persistent and excruciating itching may be given corticosteroid hormones if there are no contraindications.

Among the physiotherapeutic procedures, which produce a favourable effect in generalized pruritus, are artificial or natural (at the corresponding spa) sulphurated hydrogen or radon baths, with decoctions of oak bark or bur-marigold, or with bran (1 kg for each bath) and sea bathing. Among the external means of treatment, which cause a temporary effect in generalized pruritus, are rubbing with a 1-2 per cent alcohol solution of thymol, carbolic acid, menthol, chloral hydrate and cooling shake mixtures containing menthol. Dryness of the skin is treated by oral medication with vitamins A, B₂ and B₃, and external application of an emollient cream (Lanolini, 01. Olivarum, Aq. distill. aa 30.0).

Localized pruritus is successfully treated with diadynamic currents. Temporary relief is produced by external application of corticosteroid ointments: Synalar, Locacorten, 1-2 per cent hydrocortisone, 0.5-1.0 per cent prednisolone, 3-5 per cent boric acid-tar ointments.