122 SKIN DISEASES ulceration and resulting scar are slight (lupus non- exedens); or, on the other hand, the ulcerative process may be deep and extensive, destroying a large portion of the tissues of the nose or cheeks, and leaving deep marks with much disfigurement (lupus exedens). Another form of this disease, termed lupus erythematosus, is of compara- tively mild character, and occurs on the nose and adjacent portions of the cheeks in the form of red patches covered with thin scales, underneath which are seen the widened openings of the sebaceous ducts, this variety of the disease affecting specially that portion of the skin texture. It is very slow in disappearing, but does not leave any marked scar. Lupus is generally more frequently seen in women than in men, and it is held to be connected with a scrofulous constitution. Its treatment bears reference especially to this condition (see SCROFULA). In the superficial variety the application of soothing ointments when there is much redness, and Squire's method of slight linear incisions to destroy the increased blood supply, are often serviceable. In the ordinary form the great principle of local treatment is to remove the new tissue growth. This is most readily done either by solid points of caustic, of which the nitrate of silver is perhaps the best, thrust into the tubercles to break them up, or by means of a scoop (Volkmann's spoon) to scrape away the diseased masses. Only by such means can the ulceration be arrested and healing brought about. (b) Leprosy (elephantiasis Grxcorum) may be regarded as belonging to this class of skin diseases, inasmuch as it consists in a new growth of cell material, like lupus, but with less tendency to disintegration and with a wider dis- tribution affecting the skin, mucous membranes, nerves, &c., all over the body. For its history and pathology see vol. xiv. p. 468 sq. Leprosy is not amenable to treat- ment, beyond attempts at palliation of the symptoms and by general hygiene. (4) Pigmentary Changes. Chloasma is an abnormal pigmentation, in the form of brown patches, either gene- rally diffused or confined to one part, such as the fore- head and face, and occasionally seen in women suffering from uterine ailments. Addison's disease is connected with a morbid condition of the suprarenal capsules (see PATHOLOGY), and is accompanied with general bronz- ing of the skin, together with anaemia and great and increasing prostration. Lcucoderma is a change in the pigmentation of the skin, whereby it becomes white in patches, with a tendency to spread and affect almost the whole surface, until a few dark areas alone remain to represent the original appearance of the skin. It is some- times called white leprosy, but has no relation to that disease, nor is it of any special significance as regards the health. Albinism is an entire absence of pigment from the hair, skin, eyes, &c. The hair is usually white, and the skin exceedingly pale ; and the eye has a pinkish appearance. This condition is congenital. It occasionally exists to a partial extent in any of the textures named. III. INFLAMMATORY SKIN AFFECTIONS. These embrace the following chief varieties : (1) diffuse (erythema) ; (2) papular (lichen) ; (3) catarrhal (eczema) ; (4) vesicular (herpes, pemphigus) ; (5) pustular (impetigo) ; and (6) scaly (psoriasis, pityriasis). (1) Diffuse. This variety includes erythema (see ERYSIPELAS) and its forms, particularly erythema nodosum, which consists of spots and patches of dark red colour and slightly elevated, appearing on the front of the legs and back of the arms in young persons, mostly females. The patches continue for a number of days and then become fainter. It is supposed to be connected with rheumatism, joint pains not uufrequently accompanying it. Urticaria or nettle-rash is a diffuse redness of the skin, accompanied with wheals of raised and paler appearance, not unlike the effect produced by the sting of nettles or of insects, and attended with great irritation and itching. Certain kinds of food, such as fruit and fish, produce this eruption in some persons, as also some drugs, such as opium. It is best treated by some soothing application, such as a solution of sal volatile, to which a little chloral has been added, and by attention to the state of the alimentary canal. Roseola, which consists in the appearance of rose- coloured spots upon the body, is frequently seen in children, and is apt to be mistaken for measles, but has none of the accompanying febrile or catarrhal symptoms of that disorder, and is of brief duration. (2) Papular. Lichen, an eruption consisting of small, thickly-set, and slightly-elevated red points, more or less widely distributed over the body, and in the young some- what resembling scarlet fever, but with only slight febrile symptoms and no sore throat, usually results from digestive derangements, but apparently may also arise from exposure to the sun, and it lasts but a short time. Some forms, however (e.g., lichen ruber), are of chronic character and difficult of treatment. The ordinary form requires little beyond attenti^p to the digestive organs and the appli- cation of a soothing lotion or powder. The chronic forms are best treated by the administration of arsenic. Strophulus, or tooth-rash, or, as it is popularly termed, "red gum," an affection very common in young infants, belongs to this class of skin disorders. (3) Catarrhal. Eczema, one of the most common and important of all skin diseases, consists of an inflammation of the true skin, of catarrhal character, together with the formation of papules, vesicles, or pustules, attended with more or less discharge, and with itching and other symptoms of irritation. It may be either acute or chronic, and presents itself in a variety of forms. As regards causation, it appears impossible to assign any one condition as giving rise to this disease. It occurs frequently in persons to all appearance in perfect health, and it may in such cases be a permanent or recurring affection during a whole lifetime. Again it is.undoubtedly found in persons who possess a morbid constitution, such as the gouty or scrofulous ; but apart from any such evident associations it seems in some instances itself distinctly hereditary. Sometimes it is set up as the result of local or general irritation of the skin in certain occupations, and it may exist in connexion with the presence of some other skin disease. It is much more common in men than in women. Numerous varieties of eczema are described, according to its site and duration ; only the more important of these can be alluded to. Acute eczema shows itself by redness and swelling of the skin, with the formation of minute vesicles, and attended with severe heat and irritation. Should the vesicles rupture, a raw moist surface is formed, from which a colourless discharge oozes, which when it accumulates forms thin crusts. The attack may be general over the greater portion of the body, or it may be entirely localized to a limb or other part. It usually lasts for a few weeks and then passes off, leaving, however, a liability to recurrence. Such attacks may occur as a result of digestive derangements, or in persons of rheumatic or gouty habit, and they tend to appear at certain seasons, such as springtime. They are usually best treated by attention to the general health, and by a simple and carefully-regulated diet, while locally some soothing application, such as a weak lead lotion or a dusting powder of zinc, starch, or boracic acid, will be found of benefit. Chronic eczema shows itself in various forms, of which we note the most common. In eczema rub?-um the disease affects a part, very often a limb, as a severe form of inflammation, with great redness, and weeping or oozing
