Lupus vulgaris (known also as lupus exedens, lupus vorax) is a cellular new growth, characterized by variously-sized, soft, reddish-brown patches, consisting of papules, tubercles, and flat infiltrations, eventually terminating in ulceration and cicatrization. The disease appears differently as seen in the several forms and stages of its development. All the varieties usually begin in one and the same way.
The primary lesions are pinhead- to small pea-sized, deep-seated, brownish-red or yellowish papules, having their seat in the deeper part of the corium. They are softer and looser in texture than normal tissue, and as the disease progresses form variously sized and shaped patches. They may be so closely aggregated as to form flat infiltrations. The patches tend to be round, serpiginous, or ill defined. As the papules increase in size they may be distinctly recognized both by the eye and by passing the finger over the surface; later even reaching the size of small peas. The lesions having attained a certain size or development and being covered with imperfectly-formed epidermis, may so remain for a time, or retrogressive changes may immediately occur. They may disappear by absorption, fatty degeneration taking place, leaving a desquamating, atrophic or cicatricial tissue—lupus exfoliativus—or disintegration and destruction of the diseased skin may occur, resulting in ulceration—lupus exedens, or exulcerans. This latter is the usual course of the disease. The ulcerations are rounded, shallow excavations with soft and reddish borders. If the ulcerations are the seat of exuberant granulations, the condition is known as lupus hypertrophicus. Papillary outgrowths may occur in the healing ulcers, and a rough, verrucous condition results—lupus verrucosus.
The lesions of lupus are seldom painful. The ulcers secrete a slight or moderate amount of pus which forms crusts. Soft or firm cicatricial tissue finally results. In almost all cases of long standing the several stages of the disease may be recognized, each lesion, whether the first or the last, going through a similar course, either of absorption and exfoliation or ulceration and cicatrization. The deeper parts may be involved in the process, subcutaneous connective tissue, cartilage, and mucous membrane being liable to invasion. The mucous membrane of the mouth, gums, velum and larynx may even be primarily the seat of the lupus infiltration, considerable destruction eventually resulting. The face, especially the nose, is the most common site of the disease. Occurring about the eye, the process may eventually destroy that organ. The ears are likewise frequently attacked. Not infrequently the extremities, and occasionally the trunk, are invaded. The disease begins, as a rule, in childhood. It is always a destructive process, usually resulting in disfiguring cicatrices.
The causes of the disease are obscure. Although it usually appears in early life, it is never congenital. Heredity has little if any influence. It is comparatively rare in this country, less so in England and Ireland, but is more common in Austria, Germany and France. It is most generally observed among the strumous and debilitated, but is also frequently seen in those who enjoy all the advantages of life and who are otherwise in average health. It is entirely distinct and independent of syphilis. The French consider it a scrofuloderm (scrofulide), and yet in many cases there is clinically a considerable difference. On the other hand, cases are met with in which its close relationship, if not identity, with the scrofulodermata is not to be questioned. The view that it is a tuberculosis of the skin due to the same cause as at present advanced for tuberculosis of the lungs—the bacillus—has lately been suggested. The disease attacks both sexes, but is somewhat more common in women than in men.
Anatomically, the process is a chronic inflammation, consisting essentially of small-cell infiltration, affecting primarily the corium, eventually spreading to other parts. The epithelial structures are usually involved in the first stages of the disease. Recent lesions are rich in vessels, the vascularity when retrogressive changes take place rapidly decreasing, beginning at the centre of the nodule. The cutaneous tissues undergo cicatricial contraction, a part, however, being organized into coarse connective tissue. In addition to the formation of the nodular mass, the cell-infiltration is found to spread along the vessels of the corium and papillæ, and also into the deeper portions of the skin. The papules may be so close and the cell-infiltration so extensive that a large area of disease results and undergoes the same changes as an individual lesion. The sweat and sebaceous glands are involved. Sometimes epithelial hyperplasia takes place, the epithelial outgrowth from the rete dipping down and joining similar outgrowths from the cells of the sweat-glands and hair root-sheaths, forming an epithelial network which may become a histological basis for the development of epithelioma. The occurrence of this latter disease in lupus tissue, in association or as a sequela, has been noted by several observers. According to the latest investigations the infiltration of lupus is due chiefly to cell-proliferation and outgrowth from the protoplasmic walls and adventitia of the blood-vessels and lymphatics. The fibrous-tissue network, vessels, and a portion of the cell-infiltration are thus produced, the fixed and wandering connective-tissue cells of the inflamed stroma of the cutis being responsible for the other portion of the new growth.
DIAGNOSIS.—Ordinarily, the features of lupus vulgaris are so distinctive as to render a diagnosis a matter of no difficulty. The characteristic soft, small, reddish-brown subcutaneous papule—the primary efflorescence of the disease—is generally to be found, especially about the periphery of the patch, and when present is diagnostic. At times, however, it bears resemblance to syphilis, epithelioma, lupus erythematosus, and acne rosacea.
It is chiefly in the serpiginous forms of the late tubercular and ulcerative syphilodermata that the resemblance to lupus vulgaris is sometimes very close. There are several points of difference. Syphilis is much more rapid in its course, marked ulceration following frequently within a few weeks or months of its appearance. With lupus, on the other hand, years may elapse before the same amount of destruction results. In lupus there are usually several points of ulceration; in syphilis, one or several, which incline to coalesce. The ulcers of lupus are apt to be superficial, whereas those of syphilis are usually deep, with a punched-out appearance. Lupus papules are small, soft and but slightly elevated, and frequently reappear in the scars left by the disease; the papules or tubercles of syphilis are larger, more elevated, firm and harder, and are seldom seen in the scar or track of the disease. The secretion of the syphilitic ulcer is abundant, purulent and offensive, and the crusts thick, often oystershell-like, and of a greenish or blackish color; the secretion of lupus ulceration is slight, odorless, the crusts thin and scanty and of a reddish or reddish-brown color. The scar of lupus is generally hard, shrunken, yellowish, and more or less distorted, while that of syphilis is soft and, compared to the amount of ulceration, but slightly disfiguring. The bone-structures are not involved in lupus; they may be in syphilis. The two diseases have different histories: lupus generally begins in childhood and runs a slow and chronic course; syphilis is usually seen after adolescence or adult age, and progresses more rapidly. In syphilis, moreover, other evidences of the disease may usually be found.
Lupus vulgaris differs from epithelioma in several important points. The edges of the epitheliomatous ulcer are hard, elevated, and waxy; the base is uneven, and the secretion is thin, scanty, and apt to be streaked with blood; the ulceration usually starts from a single point; it is often painful; the tissue-destruction may be considerable; and, finally, epithelioma is, as a rule, a disease of advanced age. Lupus vulgaris differs essentially in all these particulars.
As a rule, there is no difficulty in differentiating lupus vulgaris from lupus erythematosus. The absence of papules, tubercles and ulceration is sufficiently distinctive. Lupus erythematosus is, moreover, a superficial disease, pinkish or violaceous in color, showing itself in circumscribed patches covered with thin adherent scales, and with usually evident involvement of the sebaceous glands. It rarely begins before adult age, whereas lupus vulgaris, as a rule, first appears in childhood. Attention to the ordinary characters of acne rosacea—the hyperæmia, the dilated vessels, comedones, acne papules and pustules, its advent at or after maturity, and the history—will prevent an error in diagnosis.
TREATMENT.—Lupus vulgaris is always a chronic disease, and one that calls for a guarded opinion as to treatment. Although it be removed, relapses are prone to occur, and new papules may show themselves even about the scar resulting from treatment. If it is localized the chances of permanent cure are more favorable. The deformity attending and following the disease is often great,—contraction of joints, destruction of cartilages, and sometimes partial closure of the orifices resulting. The general health is usually good. Death by tuberculosis of the lungs has been noticed in some cases.