Definition And Description

Chloasma is a designation which has been quite loosely applied, and by many writers has been made to embrace several distinct affections - to include, in fact, all brownish or yellowish brown discolorations, larger than freckles, by whatever cause produced. Some, on the other hand, confine the term to parasitic discoloration (Chromophy-tosis) while others, including Hebra. (135, 1: 77) exclude the parasitic affection but embrace both cases that arise from external and mechanical causes, and those that are symptomatic of certain internal conditions and diseases, speaking of the former class of cases under the name of idiopathic chloasma, and the latter as symptomatic chloasma The writer, however, prefers to restrict the name chloasma to certain discolora-tions of the skin of internal origin, and assigns the name melasma to cases of non-parasitic cutaneous discoloration due to external agencies.

Under these restrictions chloasma may be defined as a diffuse brownish discoloration of the skin, usually located on the forehead and cheeks. Of this two varieties may be admitted. The first occurs, according to Lom-broso (131, 4: 17), in both sexes, though more frequent in males, as a result of mental alienation; the second, the more common form, is supposed to depend on some disturbance of the uterine function, and is, of course, exclusively met with in women.

Course

Chloasma may arise during the period of pregnancy, and

Diagnosis

The diagnosis of chloasma presents little difficulty. The band-like discoloration on the forehead and the similar patches over the malar bones and neighboring integument are characteristic, the only other pigmentary lesion of these parts, at all resembling it, being the tanning which comes from frequent exposure to the sun. We can hardly conceive that any one can mistake the latter condition for the former. Parasitic discoloration (chromophytosis) does not invade the face, though occasionally seen upon the neck.

Prognosis

The prognosis of chloasma is uncertain. Some cases are permanently relieved by treatment, while others relapse continually, even after the best directed efforts for their relief. The affection sometimes disappears spontaneously after the menopause.

Treatment

In true chloasma of uterine origin it is probable that the seat of the discoloration is extremely superficial and located among the cells of the stratum corneum, and not in the deep cells of the stratum Mal-pighii.* We may therefore hope, by removing the horny layer, to remove with it the abnormal pigmentary deposit, or, at least, a portion, and by the termination of pregnancy, or relief of the uterine disorder, to prevent its reformation.

Before attempting the local treatment of chloasma an effort should be made to ascertain its cause. If pregnancy be present it is hardly worth while to attempt any treatment until gestation is over. If uterine disease be the fons origo of the trouble this must, of course, receive attention if any permanent benefit is hoped for. Having considered the etiological factors, the question of topical applications is then to be considered. The principal indication is to procure an exfoliation of the stratum corneum, under the expectation that the newly formed horny layer will be free from pigmentary deposit. There are quite a number of agents capable of destroying the superficial layers of the epidermis, and causing their exfoliation, as cantharides, mustard, iodine, and corrosive sublimate, and any of them might be used for the purpose, were it not that some of them are very apt to produce a melasmic condition that may last longer and prove more disfiguring than the original affection. Mustard is especially objectionable on this account. Of the epidermicides mentioned, corrosive sublimate is to be preferred as the least likely to produce these disagreeable sequelae. It should be used as a lotion of the strength of three to five grains to the ounce, applied two or three times a day until the stratum corneum loosens. This may then be rubbed off with a damp towel, and is replaced by epidermis less pigmented than before, or perhaps altogether normal. If necessary, the applications may be repeated, and the new horny layer removed by the same means. Instead of the foregoing, tincture of iodine, iodized glycerine, sulphur ointment, or sapo viridis may be employed as recommended by Kaposi (198, 505).

* That this is sometimes the case I have satisfied myself by microscopical examination, bat whether it is always so I do not know.

In addition, Sodii Boras, 106; Veratrum Album, 113; and Veratroidia, 113, may be considered.