(Tetter: Salt rheum)
Definition. An acute, subacute or chronic, non-contagious, inflammatory, catarrhal disease of the skin, characterized primarily by erythema, papules, vesicles and pustules, and secondarily by a variable amount of infiltration, thickening, scaling and crusting, accompanied by pronounced subjective sensations.
Symptoms. Eczema is a many sided disease; but for purposes of study four elementary varieties, the erythematous, the papular, the vesicular and the pustular are recognized. These lesions constitute the peculiar type which may remain distinctive, or at least predominate throughout the course of the disease, though the secondary forms, such as eczema rubrum, eczema, squamosum and eczema fissum, may develop. This technical division of a disease which constitutes between ages, in all countries, in all seasons, in both sexes and in all conditions of life, is necessary for the convenience of description, but it is well to again emphasize that even in the mixed types one lesion usually predominates.
Eczema erythematosum. This variety occurs in the extremes of life, in infancy and old age, usually on the face, palms, toes, or genitalia, and while the least common of the primary forms, is very pronounced. The erythematous spots may remain isolated or, rapidly spreading over a large surface, coalesce. There may be swelling, or even edema, about the eyes. There may be rough scales or fissures, or a general weeping of the surface may appear whether vesicles are visible or not. If this scaling persists to any degree, the condition becomes eczema squamosum or eczema exfoliativum. If the eruption remains well defined in small patches throughout its course, it is called eczema circumscriptum. If on opposing surfaces, as between the genital folds, it is known as eczema intertrigo and is usually associated with a muciform secretion. Erythematous eczema may be associated with other forms, especially at its borders. It may be persistent or respond rapidly to treatment, only to reappear in a short time. It is always associated with itching and burning, and in a short time. It is always associated with itching and burning, and is nearly always worse from marked changes of temperature, cold wind or excessive heat.
Eczema vesiculosum is the most typical catarrhal inflammation of the skin, and one of the most common transitional forms. While if may occur on any surface, it is often seen upon the faces of infants and young children, and upon the fingers, hands, necks and flexor surfaces of older people. Ordinarily the eruption is preceded by sensations of itching and burning, followed by a diffused local erythema, upon which, within a short time, closely aggregated pin-point to pin-head-sized vesicles appear; these may enlarge, coalesce, or rupture spontaneously or from friction, but in the end of a sticky serum is exuded which stains and stiffens linen brought in contact with it. The subjective sensations are usually improved with the rupture of the vesicles, only to become more aggravated when new vesicles are forming and always at night during the entire course of the eruption. Scratching or rubbing naturally increases the weeping so typical of most eczema. It not disturbed, the fluid exudation forms yellowish-brown crusts beneath which a moist surface is evident. When the fluid ceases to exude, and scales take the place of crusts, a squamous form of eczema may persist for a time, or a severe form may ensue from the increased inflammation and the discharge, with aggravations from itching and scratching, and eczema rubrum, with its intense red and angry appearance, is established. In a great majority of cases of vesicular eczema, the vesicular type is permanent, although the area involved may be large, because fresh vesicles develop at the margins, or because it becomes generalized. Limited to one region it is apt to run an acute course.
Eczema papulosum Lichen simplex). Pin-head-sized rounded or acuminated, bright or dull red, discrete or closely aggregated papules commonly situated on the flexor surfaces of extremities, less often on the trunk, or even generalized, but never involving the scalp, present the description of this type. It was formerly thought a form of lichen because of its tendency to remain papular throughout, and the frequent situation of the papules in the hair-follicles. A careful search may reveal tiny vesicles at the apex of some of these papules, but more often they are blood capped as the result of scratching. Closely aggregated papules may develop into a weeping patch as the result of vesiculation, or they may become scaly, lose their papular character and become a squamous eczema, which is commonly noted on the dorsal surface of the hands and on the extensor surfaces f the extremities, while the rest of the eruption remains papular. Papular eczema is often refractory to treatment, frequently relapses, and is especially memorable because of its intense itching.
Eczema pustulosum begins in the same way as the vesicular form white local erythema upon which there appears closely aggregated pustules, or there may be an intermediary vesicular state, or the vesicles and pustules may commingle in varying proportions, or neither lesion may be distinct, and yellowish or brownish crusts may cover the whole or part of the affected area. On the hairy surfaces, such as the bearded portion of the face of males, the follicles become inflamed and secondary folliculitis complicates the process, and it may even persist after the eczematous manifestation has ceased. Pustular eczema is especially fond of the strumous, cachectic patient, and appears to favor children, appearing on the face and scalp. In adults, it is sometimes found on the thighs and lower legs as well as upon the beard.
Eczema rubrum is a secondary form, and is due to an aggravation or modification of one of the primary types, especially the vesicular or pustular varieties. Redness, swelling, infiltration, exudation, bleeding, and consequent crusting are pronounced. It is most common on the face of infants, where originally it may have been a mere dermatitis, but neglect or irritation has caused this development, and upon the legs of middle-aged or old adults, especially men, who suffer from marked varicosities and often show the common varicose ulcer. The name eczema madidans has been given to that aggravated form of red, raw and weeping eczema in which the moisture constantly oozes from the surface with pronounced burning and itching.
Eczema squamosum. Scaling and infiltration are the pronounced features of this development from the chronic erythematous or papular types. The erythematous eczema is especially apt to terminate in this form, but it is well to remember that the later stages of all eczemas will show a certain degree of scaling. The scales are usually grayish-white, thin and flaky, and are scantier and more easily detached than those of psoriasis. They may involve large areas or small patches, and are frequently not typical of true eczema unless the previous history be known. In one variety of this type, eczema tyloticum, in which the palms of the hands and the soles of the feet become enormously thickened, the horny appearance will lead one to think of keratosis plantaris et palmaris.
In any type of eczema in which there is much induration, or in a location where there is a natural crease, there may be a separation of the surface leading to the condition known as eczema fissum. A mild form of eczema, usually of a squamous or fissured nature, is presented in the condition known as chapping due to cold winds, cold water, or any irritating substance even ordinary soap if too frequently used. If the infiltration of the skin is unaccompanied by inflammation, but is chronic, indolent and leathery almost to the degree of scleroderma, it is called eczema sclerosum. If characterized by watery excrescences, it is known as eczema verrucosum, or eczema papillomatosum if the papillary hypertrophy is exaggerated. The clinical feature of eczema are much modified by location, due not alone to anatomical differences, but also to external influences such as temperature and friction to which the different portions of the body are subject. To avoid repetition, the description of eczema by anatomical location is best left to the consideration of the regional treatment of the disease.
Etiology. There is not one cause of eczema. It is not respecter of persons or age and although more common in the over and under nourished, and more frequent in the extremes of life, it can occur in any period, during any season, and in any land. It is not a parasitic disease, although various bacteria may influence its course. The difference between a dermatitis caused by external irritants and an eczema excited by the same irritants rests wholly in the existence of a predisposition in the latter condition and an absence of the same in the former. Hence we consider that the cause of eczema are two-fold: constitutional or predisposing, working from within, and local or exciting, working from without. It is possible that either one might cause the development of a case of eczema independently of the other, but usually they are associated in the causation. If the predisposition exists, local irritants which ordinarily would cause no damage might bring about the disease.