Page:Encyclopædia Britannica, Ninth Edition, v. 22.djvu/139

 SKIN DISEASES of serous matter from the raw surface. It gives rise to great irritation and pain, and may cause considerable disturbance of the general health. It may last for years, with intervals of partial recovery, but easily recurring. The skin of the limb becomes in time thickened and the limb itself much swollen. In dry eczema the skin, though irritable, remains dry and scaly. In pustular eczema, or eczema impetiffinodes, in addition to the cutaneous inflam- mation there occur pustules which break and the purulent matter forms yellow crusts upon the skin. This form is very common on the heads of young children during the period of dentition. The treat- ment of chronic eczema depends in great measure upon the form it assumes. Where there exists much irritation, soothing lotions or applications similar to those required for acute eczema are necessary ; but where irritation has subsided, stimulating ointments, such as those of zinc or white precipitate, are often of service. Constitutional remedies, such as iron, arsenic, Arc., are an important and often essential part of successful treatment. (4) Vesicular. Herpes is an inflammation of the true skin, attended with the formation of isolated or grouped vesicles of various sizes upon a reddened base. They contain a clear fluid, and either rupture or dry up. Two well-marked varieties of herpes are frequently met with. In herpes labialis et namlis the eruption occurs about the lips and nose. It is seen in cases of certain acute febrile ailments, such as fevers, inflammation of the lungs, or even in a severe cold. It soon passes off. (6) In herpes zoster, zona, or shingles, the eruption occurs in the course of one or more cutaneous nerves, often on one side of the trunk, but it may be on the face, limbs, or other parts. It may occur at any age, but is probably more frequently met with in elderly people. The appearance of the eruption is usually preceded by severe stinging neuralgic pains for several days, and, not only during the continuance of the herpetic spots, but long after they have dried up and disappeared, these pains sometimes continue and give rise to great suffering. The disease seldom recurs. The most that can be done for its relief is to protect the parts with cotton wool or some dusting powder, while the pain may be allayed by opiates or bromide of potassium. Quinine internally is often of service. Pemphigus consists in large blebs upon a red base. They contain clear or yellowish fluid. This disease appears to show itself most frequently on the bodies and limbs of unhealthy or neglected children. The blebs give rise to much irritation, and when they burst leave raw- ulcerated surfaces which are slow of healing. One variety of this malady (pemphigus foliaceus) affects the entire skin of the body, from which there exudes a constant discharge. This form is apt sooner or later to prove fatal from its exhausting effects. The treatment is mainly con- stitutional, by good nourishment, iron, tfcc. (5) Pustular. Impetigo, consisting of small pustules situated upon a reddened base, mostly occurs in children. There appears to be a contagious form of this malady. Ecihyma consists of large pustules of similar character on the body and limbs. The treatment of these ailments requires special attention to nutrition, since they usually occur in low states of health. (6) Squamous or Scaly. Psoriasis, an inflammatory affection of the true skin, attended with the formation of red spots or patches, which are covered with white silvery scales, may affect any portion of the surface of the body, but is most common about the elbows and knees, and on the head. There is as a rule comparatively little irrita- tion except at the outset, but there is an extensive shed- ding of the scales from the affected spots. Varieties of this disease are described in relation to the size and dis- tribution of the patches. The causes of psoriasis have given rise to much discussion, and, while some authorities regard its appearance as in many instances connected with some constitutional morbid state, such as gout, rheumatism, .Arc., the majority deny any such relationship, and mention hereditary influence as the only recognizable cause, although it must be admitted that even this evidence is wanting in a large number of cases. The disease appears to be consistent with continued good health. It is usually obstinate to treat, and may, with intervals of comparative immunity, last a lifetime. The remedies most serviceable are arsenic internally and the application externally of preparations of tar. Recently the employment of chrysophanic acid as an ointment or in solution has been resorted to with considerable success. Pityriasis, a superficial inflammation of the skin, with the formation of minute branny scales, occurs most com- monly on the head, and is of chronic duration. The remedies most useful are alkaline lotions and tar prepara- tions. A variety of this disease (pityriasis rubra) affects the whole body, and is most intractable to treatment. IV. XEUROSES (Nervous Affections). Various disorders of nutrition of the skin occur in persons suffering from organic nervous diseases, such as bedsores, atrophic changes, eruptions, <tc., but these belong to the symptoms of the several diseases with which they are associated. The most common of the neuroses of the skin is probably pruritus, which is an ailment characterized by intense itching of the surface of the body. It may occur in con- nexion with other morbid conditions, such as jaundice, diabetes, digestive disorders, ttc., or as the result of the irritation produced by lice or other skin parasites. The most serious form is pruritus senilis, which affects old persons, and is often a cause of great suffering, depriving the patient of sleep (the malady being specially trouble- some during the night). In such cases it is probably due 'to atrophic changes in the skin. No eruption is visible, except such marks as are produced by scratching. The treatment consists in the removal of any apparent cause, and measures to strengthen the system, such as the use of quinine, iron, &c. Soothing lotions composed of solutions of alkalis conjoined with chloral, opium, hydrocyanic acid, lire., may be applied to the affected skin at bedtime. V. PAEASITIC DISEASES. (1 ) Animal. The following are the chief animal parasitic diseases. Phthiriasis is produced by the presence of lice (pedicit/i), of which there are three varieties, infesting respectively the head, body, and pubis. The cause is in most instances uncleanliness, but occasion- ally in the aged, and in persons suffering from chronic diseases, there appears to be a liability to the development of pediculi, notwithstanding every care to prevent it. The irritation produced by the parasite and the scratching thus occasioned may give rise to abrasions of the skin and eczematous conditions. The treatment consists in thorough cleansing of the parts and the use of parasiticides, such as red or white precipitate, carbolic lotions (one in twenty), or a decoction or ointment of stavesacre. Where clothing is infested it should be destroyed or subjected to a strong heat to get rid both of the parasites and their ova. Scabies or itch is a skin affection due to the Acarus scabiei (see MITE). The female insects burrow into the upper layers of the skin and deposit their eggs in the tract thus made. Great irritation of the skin is set up, and scratching pro- duces eruptions which aggravate the condition, especially at night. The most frequent sites are the parts between the fingers, or the wrists, but by scratching the disease may be conveyed to any part of the body, and in extreme cases the greater portion of the surface of the trunk and limbs may be involved. In infants the feet and buttocks