A system of practical medicine. By American authors. Vol. 4

by Unknown

⁵ Purpura, constituting Class III., appears in Vol. II. p. 186, as a separate article by I. E. Atkinson.

Lentigo.

Lentigo, or freckle, is characterized by irregularly-shaped, rounded or angular, pinhead- or pea-sized, yellowish or brownish spots of pigment deposit, occurring for the most part upon the face and the backs of the hands. They may appear as blemishes scarcely perceptible to the casual observer, or to such an extent and with such intensity of color as to be disfiguring. They may show themselves as discrete or as confluent lesions, and in the latter event the skin presents a spotted, rusty, or dirty appearance. As stated, the face and the backs of the hands are usually attacked, but other regions may also be invaded. They are encountered at all ages, but usually in young persons, especially in those of light complexion, and more particularly in red-haired subjects. They pursue a chronic course, lasting, as a rule, a lifetime, being, however, in most cases much paler in winter than in summer. Sometimes the lesions are blackish rather than brownish, and cases are on record where such were numerous and occupying the general surface. Blackish freckles are also met with in connection with certain rare forms of atrophy of the skin proper complicated with telangiectases, as in the cases reported by Hebra and Kaposi, Taylor, and one of us (Duhring), an account of which may be found under atrophy of the skin.

The affection consists of a circumscribed deposit of pigment, which in the majority of cases is due to the influence of the sun's rays, but there are cases in which the lesions cannot be assigned to this cause, as, for example, where they occur upon the trunk or other regions not exposed to light. The treatment will be referred to in connection with chloasma.

Chloasma.

Chloasma may be described as a pigmentary affection, consisting of variously sized and shaped, more or less defined, smooth patches of a yellowish, brownish, or blackish color. The affection is one merely of coloration, the structure of the skin proper being normal. The spots or patches vary much as to size and shape. As a rule, they are irregular in outline, and not infrequently they are angular. They vary in size from a small coin to a hand or larger. At times the affection may develop as a diffuse or even as a universal discoloration. The distribution of the pigment may be uniform, but more frequently it is mottled, giving the skin a thick, muddy, or dirty appearance. Under idiopathic chloasma are included the forms of pigmentation due to various external agencies, as, for example, chemicals, sinapisms, heat, and long-continued scratching. The symptomatic group comprises uterine chloasma and the discolorations occurring in connection with certain general maladies, among which cancer, tuberculosis, Addison's disease, and malaria may be mentioned. Chloasma is also met with as a symptom in certain diseases of the skin proper, as scleroderma, morphoea, leprosy, and syphilis.

Chloasma uterinum, the commonest form, appears in all degrees from a duskiness or swarthiness of the complexion to pronounced patches of mottled yellowish or brownish discoloration, occurring on the face usually of pregnant women. But the same condition is met with also in single women, and at times in men. In women it usually appears as a more or less broken patch invading the forehead, extending from temple to temple, but the nose, cheeks, and chin are likewise very frequently attacked. It is due both to physiological and to pathological changes in the uterus, and also to various disorders of the menstrual function. The nervous system in many cases is without doubt at fault, and to this cause must be assigned those cases occurring in men. It is encountered, as a rule, between the ages of twenty-five and fifty. Its course is variable, depending upon the cause, but, as a rule, it is persistent, and it may continue for a long period. It is liable to be confounded with tinea versicolor, from which, however, it may be readily distinguished by the observation that in the latter disease the surface of the skin is the seat of more or less furfuraceous desquamation, which becomes more evident by scraping. In chloasma the skin is normal in structure. The patches of tinea versicolor are usually more numerous than those of chloasma, and occupy the trunk, a region seldom invaded by the latter affection. The face is the common seat of chloasma, a region practically exempt from tinea versicolor.

The treatment consists in removing the cause where this is possible, or in modifying it by such general remedies as appear indicated. Among the various local remedies corrosive sublimate is one of the most valuable, used in the form of a lotion with water, alcohol, or almond emulsion. Its strength should vary from half a grain to five grains to the ounce, according to the region, size of the spot, sensitiveness of the skin, and the effect produced. Two or three grains to the ounce will generally be found of sufficient strength; and this may be applied, dabbed on lightly for five or ten minutes, twice daily, until irritation or desquamation appears. A lotion recommended by Hardy is the following:

Rx.	Hydrargyri chlor. corros.,	gr. viiss;
	Zinci sulphatis,	drachm ss;
	Plumbi acetatis,	drachm ss;
	Aquæ,	fluidounce iv. M.

Ammoniated mercury, from forty to eighty grains to the ounce of ointment, may also be referred to as of positive value.