Among the most common as well as perplexing cases of skin disease met with by the dermatologist and general practitioner, eczema justly occupies a prominent place, assuming as it does a multitude of forms, general and local, acute and chronic, and appearing so universally among all classes of society, the rich as well as the poor, the ignorant and the well educated, and arising from the most varied causes.
An accurate and at the same time concise description of eczema is impossible in view of the fact that the disease presents so many forms and phases and that of a dozen consecutive cases no two may look alike or even bear what ordinarily would be termed a family resemblance. These differences are due to the occurrence of lesions which may be quite dissimilar in character and appearance, and combined in ways and proportions almost with- out number. The aspect, too, of the individual lesions varies somewhat with the location they occupy, the degree of activity they present, and the length of time they have lasted.
The varieties of eczema dependent on the primitive or characteristic lesion are six in number-namely, erythematous, vesicular, pustular, nodosae, papular, and fissured; and these in their progress may undergo changes and become complicated with or give place to certain secondary lesions.
The varieties of eczema dependent on the activity of the process may be classed as acute and subacute, while those that run but a short course may also be termed acute, and those of longer duration chronic.
Location greatly influences the appearances presented by eczematous lesions, and the principal modifications met with in this connection are those seen on the scalp, face hands and feet, genitals, and about the anus. Eczema may also invade the follicular apparatus of the skin, and give rise to an eczematous affection of the hair-follicles and of the sebaceous glands.
We will best understand the appearances presented by this protein malady if we trace the course of a simple acute eczema of the general surface. It commences with a local congestion, or erythema, followed in a few hours, perhaps, by a crop of minute, closely aggregated vesicles filled with a clear, transparent serum. It often takes a sharp eye, and even a lens, to distinguish their separate contours. When closely examined, we find them to consist of a very thin and delicate epidermic covering, which for a brief period retains the lymphy exudation that is seeking an exit. Rubbing, scratching, or other violence from without, or the pressure of the exudation from within, soon ruptures the epidermis, and usually in twenty-four or thirty-six hours the vesicles have disappeared, and we find in their place a red and exposed surface more or less moist with exudation. If exposed to the air, the watery portions of the exudation evaporate, and light, straw colored crusts remain. As the exudation continues, the crusts thicken until they drop off, or are purposely removed. After a varying period (days or weeks as the case may be) the crusts lessen or cease to form, and nature makes an attempt to cover the part with a new layer of horny epithelial cells.
It may be weeks before this effort is entirely successful, and the affected surface presents in the interval a reddened and somewhat glossy surface scantily covered with loosely attached scales of small size, the scales being composed of embryonic horny cells which have not yet attained a normal character and consistence. Those first formed are less visable than the normal cell, and are quickly shed, to be replaced by others of more natural character and aspect, until finally we find a complete regeneration of the epidermis, and a return to the condition which existed before the appearance of the attack. In eczema pure and simple we never have ulceration or loss of tissue, and recovery takes place without the least trace of scarring.
For practical convenience the course described above may be divided into three stages: the first being that of congestion and vesicle formation, the second that of exudation and crusting, and the third that of dryness and scaling.
The pustular variety of eczema pursues the same course and passes through the same stages as the vesicular, and differs from it only in the character of the exudation and the color of the crusts in the second stage. Instead of transparent, lymphy exudation we have a purulent one, and the crusts are of a greenish color. In the vesicular form the number of leucocytes in the exudation is limited, while in the pustular they are abundant. The third stage of both varieties is identical, and if a case be seen in this stage it is impossible to determine, except by the patient’s recital, whether the eruption had been characterized by vesicles or pustules.
The nodosae, or exfoliative form differs from, the preceding forms by the fact neither vesicles not pustules are observed, but instead a rapid loosing and exfoliation of the horny layer over the whole or greater part of the affected area. The succeeding exudation may be serous, sero-purulent, or purulent and crusts form as already described. In the second and third stages the appearances are the same as those presented by the two first- named varieties.
In the papular variety an area of congestion becomes the seat of small scattered or aggregated papules, with little if any tendency to exudation unless the papules be wounded by scratching. In this case a small quantity of lymph may exude and dry into a minute scale or lamina.
The papules after a time subside and the surface becomes somewhat glossy and scaly, but not to the extent met with in the varieties already described. The arms and forearms, and the thighs and legs, especially the flexor aspects, are the favorite seats of papular eczema, although it is sometimes met with on the face.
In the fissured variety we have more or less reddened surface without vesicles, pustules, or epithelial exfoliation, but instead presenting small cracks or fissures extending through the stratum corneum, and sometimes through the stratum Malpighii as well. Exudation is slight, crusting is absent, and the skin after a time returns to the normal condition by simply closing of the fissures and disappearance of the congestion. The palms and soles are the favorite seats of this variety.
The erythematous variety is characterized simply a red and congested patch of varying extent, and is not accompanied with vesicles, pustules, papules, or the other lesions of the disease.
Cases of eczema vary in respect to the grade of inflammation present. In one it may exhibit great activity and be accompanied with decided heat, high color, and other evidences of marked inflammatory action, in either the first or second stages or in both; and this activity may continue for an indefinite period, and until the case prepares to enter the third stage. On the other hand, the natural color may be but slightly altered, the increased of local heat be almost inappreciable, and the general process partake of a subacute character from the beginning. In other cases, again, an eruption which is subacute may at any stage of its progress suddenly assume an acute phase, or there may be frequent alternations of activity and comparative quietude. This is a very striking feature of eczema, and one that should always be borne in mind. A case may be progressing nicely under treatment, and with the prospect of early recovery, when suddenly the trouble may relapse into its previous active state, and often apparently without sufficient provocation.
The duration of eczema varies. In some cases it may run its course in a few days or weeks, while in others it may be prolonged for months or years, constituting the chronic form of the affection; or again, there may be frequent relapses, even after complete disappearance of the individual attacks.
The location of an eczema greatly influences its appearance, and exhibits also preference for certain varieties of lesion. Thus, in eczema of the scalp, especially in infants and children, the process is usually acute, with profuse lymphy or purulent exudation, which mats the hair together in a tangled mass, offensive to both sight and smell. If by chance pediculi find lodgment in such a scalp, they multiply rapidly, and by their irritation increase and aggravate the trouble. If proper care and cleanliness are not practiced, the scalp may become a mere mass of animated filth.
When eczema attacks the scalp in children, it frequently extends to the face, presents an active form of inflammation of the vesicular, pustular, or nodosae type, accompanied with a good deal of heat and pruritus. If it extends behind the ears, fissures may form.
In adults, eczema of the scalp is usually of the subacute form, without much exudation; and on the face it may be of the erythematous type, without other lesion.
When the palmar and plantar surfaces are attacked by eczema, we may have a purely erythematous lesion, characterized by a red, dry and glossy surface, on which the natural skin lines are greatly exaggerated as to size and distinctness, and many lines appear which are not noticeable in the normal condition. In addition fissures may form, accompanied with slight exudation. This type of the disease is the most common, and is usually subacute and chronic. On the other hand, we may have an acute eczema of the hands and feet, accompanied with vesicle formation. In consequence of the thickness of the horny epidermis on those parts, the vesicles do not easily rupture, but instead retain their integrity, and even become larger, and remain as vesicles until absorption of the contents occurs, when what was the summit of the vesicle separates as a small scale.
