Lupus erythematosus (also known as lupus erythematodes, seborrhoea congestiva, and lupus sebaceus) is a small-celled new growth, characterized by one or more circumscribed, variously sized and shaped, reddish patches, more or less covered with adherent grayish or yellowish scales. The affection usually begins as a rounded, circumscribed, pinhead- to pea-sized, slightly elevated lesion, which increases in size by peripheral extension until considerable surface is involved; or, as is often the case, the disease starts with several such spots, which grow and generally coalesce, sooner or later involving considerable surface. The spots are at first erythematous and slightly scaly, with but little elevation, later becoming thickened, with a more or less raised border sharply defined against the healthy skin, covered with small, firmly adherent yellowish or grayish scales, with enlarged and plugged or patulous follicles, the centre of the patch being somewhat depressed. The color is pinkish, reddish, or violaceous. In the beginning the disease often closely resembles seborrhoea,—so much so that it was originally described by Hebra as seborrhoea congestiva. The scaling is usually scanty, but in exceptional instances may be abundant. At times the lesions show little tendency to peripheral growth, the large areas of disease resulting from the continuous appearance of new patches in proximity which run together. Occasionally the patches are small, discrete, and numerous, when the disease is apt to be disseminated over considerable surface.

Lupus erythematosus is seen most frequently about the face, one or several patches, varying in size from a pea to a silver dollar, ordinarily being present. The nose and the cheeks are favorite localities, and, seated here, the disease is apt to be symmetrical, extending from one cheek across the nose to the other cheek, in shape representing rudely the outline of a bat or butterfly with outstretched wings. The lips, ears, scalp, and other parts of the body are often affected. The progress of the disease is variable; the patches, as a rule, reach a certain size, and then remain stationary or retrogress, or, as generally happens, the central portion becomes depressed and more or less atrophied. The resulting scar is whitish, usually soft, punctate, and superficial. As old patches disappear it is not uncommon to see new patches appearing close by. It is essentially a chronic disease: the individual lesions may be acute in their course, and when such is noted, as a rule new areas of disease continue to appear in rapid succession. Ordinarily, however, the individual patches themselves are chronic in their course. The disease is not attended with ulceration. The subjective symptoms of itching and burning are usually mild in character, and sometimes are entirely wanting.

The condition of the general health is, as a rule, good. The disease is seen more frequently in women than in men, and is rarely observed before puberty, being chiefly encountered in early adult and middle age. The causes are not known. It frequently begins as a seborrhoea, but it may occur (although rarely) upon the palms of the hands, where sebaceous glands are not to be found. It is a notable fact, however, that the disease is most commonly encountered in those who are subject to disorder of these glands. It is observed more often in persons of light complexion. It is comparatively rare. The condition of the general health apparently exercises no causative influence.

Pathologically, the process is essentially a chronic inflammation of the cutis, superinducing degenerative and atrophic changes. In the majority of cases the disease originates in the sebaceous glands, but later all parts of the skin become affected. It is even authoritatively stated that it may in some instances take its start in the subcutaneous connective tissue. In some respects it has the character of a new growth, which until late years it has been considered. In the light of recent investigations, however, it seems possible that it may be a chronic inflammation leading to degenerative changes. The process never ends in the formation of pus. There is small-celled infiltration about the follicles and glands, the blood-vessels are dilated, the surrounding tissue is infiltrated with embryonic corpuscles, and the sebaceous glands are enlarged and their walls infiltrated with small cells. The whole affected area is, in fact, infiltrated with a small-celled inflammatory new growth. If retrograde changes occur, the infiltration may disappear by absorption without leaving a trace. On the other hand, and as is usually the case, degenerative metamorphosis, resulting in absorption and atrophy, takes place.

There is very little difficulty in recognizing a fully-developed patch of lupus erythematosus, as its features are usually characteristic. The sharply circumscribed outline, the reddish or violaceous patch with elevated border, the tendency to central depression and atrophy, the plugged-up or patulous sebaceous ducts, the adherent grayish or yellowish scales, together with the region attacked (generally the nose and cheeks), are characters which, when taken together, are common to no other disease. Lupus vulgaris may be excluded by the absence of papules, tubercles, and ulceration. The sebaceous involvement and the peculiar atrophy and superficial scarring are, moreover, not seen in lupus vulgaris. Erythematous lupus begins, as a rule, during adult life; lupus vulgaris usually in childhood. In psoriasis the course and symptoms peculiar to that disease will distinguish it from lupus erythematosus. It is scarcely possible to confound the disease with eczema or syphilis. In some cases in the beginning of the affection it may resemble seborrhoea; in fact, it often has its starting-point in that disease. The inflammation, infiltration, sharply-defined characters, atrophy, and scarring are absent in seborrhoea.

TREATMENT.—The prognosis of lupus erythematosus, as regards the general health and welfare of the patient, is good, but respecting the disappearance and cure of the disease an opinion should always be guarded. Occasionally the patches yield readily, but, on the other hand, cases are frequently met with that prove exceedingly rebellious, responding only after long-continued treatment. Constitutional remedies are in most cases of but little value. Occasionally arsenic and cod-liver oil, used continuously for a long period, prove serviceable. Iodized starch, in the dose of one or two teaspoonfuls three times daily, has been recommended, and in some cases potassium iodide has a favorable influence.

It is to the external treatment, however, we look for positive effects. In the selection of remedial applications it is to be remembered that the patches of disease sometimes disappear spontaneously, occasionally with little or no scarring, and therefore treatment that would have as an effect marked scarring or disfigurement is to be avoided. The simplest remedy, at times useful, is soft soap, the sapo viridis of the shops. This may be used as such or in solution in alcohol, two parts of the soap to one of alcohol, constituting the well-known spiritus saponatus kalinus. It is to be energetically rubbed into the diseased parts once or twice daily. The application of the sapo viridis as a plaster is a more energetic method. After several days the soap is to be discontinued and a soothing ointment applied. In addition to its therapeutic properties, sapo viridis—or, better, its alcoholic solution—may be advantageously employed to cleanse the parts preparatory to other remedial applications. Mercurial plaster constantly applied to the patches will in some cases effect a cure. A 10 to 25 per cent. oleate-of-mercury ointment, rubbed on the parts once or twice daily, is sometimes of value.

In almost every case where the inflammatory symptoms are marked the following lotion will prove palliative, and in some cases of the mild and superficial form of the disease it has in time effected a cure:

Rx.Zinci sulphatis,
Potassii sulphidi, aa.		drachm ij;
Aquæ,fluidounce iij;
Alcoholis,fluidounce j.