Psoriasis Vulgaris (Diffuse Dry Teeter— see Plate XXV.) is a chronic disease of the skin, in which thick layers of shining pearly scales are formed on a reddened and thickened skin. The scales are easily separated by the nails. There is little or no itching, and thus, in one chief point, psoriasis differs from eczema. Large portions of the skin may he affected, or the eruption may occur in little heaps, of the size of pin heads, which gradually enlarge till masses like drops of mortar are produced, and still enlarging may become like coins in size. These patches tend to heal in the centre and spread at the circumference, circles and figures of 8 being produced. As the disease heals, the patches become less raised, the scales being detached, and others not being formed with the same rapidity, and the redness gra dually fades till the skin resumes its natural colour. The most common places for psoriasis are the backs of the elbows and the front of the knees. It may also form a ring round the forehead and ears.
Psoriasis may be cured, but is always liable to return. It is not contagious, but is distinctly transmitted from parents to children.
Treatment.—The most successful application is made of a powder called chrysophanic acid, of which 15 grains are combined with 1 ounce of lard or vaseline. This may be rubbed on the part at once, or after scales have been removed by the use of soft soap. If it irritates too much the ointment may be weakened or discontinued for a time. It stains clothing a deep colour not removed by ordinary washing. Benzole, how ever, or a weak solution of potash or chlori nated lime will remove the stains. Of more recent remedies, pyrogallic acid ointment (60 grains to 1 ounce of lard) is also useful. It is commonly necessary to combine with the ointment the internal administration of arsenic. A good way of avoiding a mistake with the dose is to have the drug put up in pill, each pill containing 2 grains dried sulphate of iron, nth of a grain arseniate of soda, and 1 grain extract of gentian. One pill should be taken thrice daily after meals. The pills should be continued for a long period, should never be stopped abruptly, but, when it is desired to cease taking them, the dose should be gradually diminished-2i pills daily, then after some days 2 pills daily, and so on, till, after the lapse of a fortnight or so, the dose has been gradually reduced to nothing. On the whole, however, such drugs should not be taken without the direction and guidance of a physician; and no one, of course, would give such a medicine to children unless the correct dose were regulated by a medi cal man.
The internal administration of thyroid ex tract in extensive cases of the disease produces sometimes remarkable results ; the affected skin being shed in sheets, leaving healthy skin in its place.
Dandruff (Brawny Tetter—Pityriasis) is a chronic disease of the skin in which a quantity of fine scales is continually being produced and shed. The skin is sometimes slightly red, and
there is some amount of itching present. Any part of the skin may be affected, but the scalp is specially apt to be the seat of the disease, chiefly in children and old persons. It is a very chronic affection. The distinguished German authority on skin disease —Hebra----has shown it to be really due to excessive secretion of the glands connected with the hair follicles—the sebaceous glands (p. 414).
Treatment.—A free use of soap is advised, or the use of an alkaline solution, such as the car bonate of potash (salt of tartar), of the strength of 60 grains to the half-pint of water. An oint ment consisting of one part of red precipitate ointment and three of lard is useful for the scalp.
Impetigo, Plate XXV. (Pustular Tetter Honey Sickness—Honey Scab).—This is an in flammation of the skin in which a flattened eruption containing matter is formed. The matter soon dries up and leaves yellow crusts or scabs. When the scabs are removed a raw surface is left. Heat and itching are severe. It occurs on the face and head and sometimes on the hands. It is accompanied by feverish ness and sensations of chilliness. The disease runs its course in about a fortnight, but may be prolonged by successive crops. The matter of the pustules is capable of producing pustules on healthy parts by being inoculated.
Treatment.----Remove the scabs by the use of the lysol application (p. 423). Thereafter the ointment recommended in the immediately preceding article, with the addition of 20 drops of carbolic acid, well mixed, is to be applied to the affected parts.
Lichen Simplex, Plate XXV. (Strophulus —Red-gum Rash).—Lichen is characterized by an eruption of minute red pimples, which last about five or six days, are accompanied by much local irritation, itching, and tingling, and sometimes constitutional disturbance such as headache and feverishness, and whose dis appearance is followed by slight shedding of scales of the skin. The pimples are solid, that is contain no fluid, and make the skin feel very rough. The face or arms are usually affected, but other parts also. The tops of the pimples may be torn off by scratching, and a minute crust of blood may cover them, altering the appearance of the eruption. The eruption may be mistaken for measles.
Strophulus, Red Gum, or Tooth Rash, appearing in infants, is similar to the eruption of lichen, and has been classed with it.
Treatment.—Mild opening medicine should be given, to children fluid magnesia. Tepid baths are of great use in allaying irritation, and should be frequently employed, specially the lysol bath, for a child a table-spoonful of lysol thoroughly stirred into the ordinary child's bath. All irritating agents should be removed from contact with the skin. Thus flannel should not be worn next the skin. Plain diet, milk, &c., is the most suitable. Internal remedies are sometimes necessary, but these should be prescribed by a physician.