Lupus is a chronic disease of the skin, in which dull or livid tubercles are developed, having a tendency to destroy or so seriously to affect the adjacent tissues, with or without ulceration, as always to lead to indelible cicatrices. It was formerly known as noli me tangere. The disease usually attacks the face, especially the alæ of the nose and the lips, but may occur on almost any part of the body. It usually begins in childhood or early adult life, but may recur at a later period. It more often affects the female sex, and is not contagious, nor usually hereditary. It is, in its severer forms, a terrible disease, but is happily of somewhat rare occurrence. It derives its name from the Latin lupus, 'wolf,' in consequence of its destructive nature. See TUBERCLE.
Lupus usually commences with the appearance of one or two circular or oval, dull-red, somewhat translucent tubercles, about two lines in diameter. After a time these tubercles increase in number and size, and take on new characters. They may ulcerate, constituting the variety known as Lupus exedens, in which case the ulceration may pursue a superficial or a deep course. Scabs are formed over the ulcers; and as these scabs are thrown off the ulcer beneath is found to have increased in extent, till great destruction of the soft parts and (in the case of the nose) of the cartilages is effected. The ulcer of lupus has thick red edges, and exudes a fetid, ichorous matter in considerable quantity. When they do not ulcerate, the tubercles are softer than in the previous variety, and form patches of considerable extent, the intervening skin and cellular tissue also swelling and exhibiting here and there dull-red points, which are the summits of the imbedded tubercles. The lips become much enlarged, the nostrils closed with the swelling, the eyelids everted, and the whole face hideous. This variety is known as Lupus non exedens.
The progress of lupus is usually slow, and the sufferings of the patient less than might be expected, in consequence of the sensibility of the parts being diminished from the first. The complaint may continue for years, or even for life, but is seldom fatal. Its causes are not well known; it is thought that a scrofulous habit predisposes to the disease, but in many of those affected the health is otherwise excellent. A bacillus has been found in the diseased tissues, never abundantly, which is indistinguishable from the tubercle bacillus; but lupus is so rarely associated with tuberculous disease elsewhere that it is doubtful whether the two organisms are actually identical.
Treatment.—It is of course desirable that the patient's general health be brought into as vigorous a condition as possible; and for this purpose cod-liver oil, iodide of iron, and other tonics are often useful. But no internal remedy seems to have any reliable effect upon the disease. The local treatment has passed through many variations: the application of strong escharotics, repeated incisions, or scraping away of the diseased tissues, were often successful in modifying or arresting the disease. Less severe measures, however, first recommended in 1886 by Unna of Hamburg, have proved very efficacious. Chief among these is the constant application to the diseased parts of plasters made for the purpose, containing salicylic acid, which, while it has little effect upon the healthy skin, causes gradual breaking down and removal of the diseased tissues, and creasote, which greatly diminishes the pain caused by salicylic acid alone. Under any method of treatment, however, the disease is apt to be obstinate and troublesome.