a scar. This distinction, however, is of little value, since the growth is the same in either case, and it is impossible to assert, in any case of spontaneous keloid, that it has not been preceded by some prick or slight injury to the skin. A distinction, however, may be justly drawn between keloid and a hypertrophic cicatrix. Many scars, especially those following burns, are prone to pucker and bulge until a tumor is formed which looks very much like keloid, being rounded, smooth, reddened, and often very firm and even painful. But while keloid is characterized by a marked tendency to enlarge its area by the forma-
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Fig. 58.—Keloid.
tion of claw-like processes suggestive of a crab, and to persist indefinitely, the hypertrophic cicatrix never extends beyond the limits of the scar tissue and tends to a gradual disappearance rather than to an increase in size.
Keloid is usually single, but many tumors may be present, and in some cases these attain considerable size. The growth is commonly painful when squeezed or pressed, and sometimes a continuous burning or pricking sensation is experienced. A spontaneous disappearance of the tumors has been reported, but this is exceptional. Keloid occurs at all ages, affects various portions of the body in both sexes, and is especially common in the negro race. The tumors increase in size for a certain time and then often remain stationary for years. A characteristic peculiarity is their tendency to return quickly whenever excised. A spontaneous disappearance of keloid is more likely to occur in childhood than in adult life, and tumors developing upon large scars are more likely to disappear than those which seemingly spring from the normal skin. A favorite site of keloid is the sternal region, where it often appears in adults as an elongated flattened tumor crossing the median line in a transverse direction. Its frequent occurrence in this locality has been attributed to the common custom of applying blisters to this part for the relief of acute pulmonary affections. It also is seen frequently upon the scalp, face, neck, and trunk.
The treatment of keloid is usually discouraging. Excision, as has been remarked, is usually followed by a return of the growth. Good results have been obtained by deep linear scarification and the application of glacial acetic acid to the cuts, and also by the use of the electrolytic needle. Subcutaneous injections of thiosinamine have been recommended, and in hypertrophic cicatrica I have known this to be followed by benefit. The results from the subcutaneous use of this drug in lupus, psoriasis, and certain other skin diseases have not proved to be as beneficial as its enthusiastic advocates of a few years since were disposed to claim. But in the relief of corneal opacities and cicatricial contractions it has apparently proved of value. Whether its use in true keloid will effect even a notable improvement remains to be demonstrated; but in cases of scar keloid which are tending to recovery it might, at least, be tried in connection with the fatty inunctions and frequent massage which seem to do some good and certainly do no harm.
Scabies is a disease which in this country has notably increased in frequency during recent years. In most cases it is readily recognized by the characteristic location of the excoriated papules which mainly constitute the eruption. The disease, as is well known, is due to the burrowing of the acarus or itch-mite in the soft skin between the fingers and elsewhere, and is usually communicated by sleeping with, or in a bed which has been occupied by, a person affected with the disease. The mature, impregnated female alone makes the burrow in which the eggs are deposited, and dies after performing this function. In recent cases the burrows or cuniculi in which the female acarus has deposited her eggs may be found upon the web of the