A system of practical medicine. By American authors. Vol. 4

by Unknown

In some cases excitants, external or internal—as, for example, cutaneous irritants and intestinal worms—may determine an outbreak. In like manner, dentition and vaccination may call forth the disease. Among the local causes producing the so-called artificial eczemas the preparations of mercury, sulphur, croton oil and tincture of arnica are most notable. Contact with the several varieties of the rhus plant, though usually producing a peculiar dermatitis, may in eczematous subjects provoke a genuine eczema. Heat and cold, especially the rays of the sun, are also factors to be considered, while it is well known that the disease in many instances is influenced by the seasons, being, as a rule, worse in winter than in summer. There are many subjects who suffer only in winter. In sensitive skins water, soap, alkalies and acids, all prove more or less injurious, giving rise to harshness or chapping of the skin, and sometimes to eczema. In the same manner the presence of parasites and the consequent scratching are productive of more or less simple dermatitis, and in eczematous subjects the disease under discussion. Eczema is not contagious, a question which is frequently asked by the patient.

PATHOLOGY.—The changes which occur in the skin in the various eczematous conditions are somewhat different as the process is of short or long duration and mild or intense in character. In all cases hyperæmia and exudation, constant symptoms of all inflammations, are present, varying according to the activity and duration of the process. The rete mucosum is also involved in all cases, being oedematous and infiltrated. In the erythematous form the blood-vessels of the papillary layer are dilated, exudation and congestion as well as increasing activity of the rete taking place. In the papular variety the process is mainly limited, primarily at least, to the follicles. The exudation is confined to small circumscribed areas and gives rise to papular elevations. In the vesicular variety fluid exudation occurs in the upper strata of the corium and in the rete, and the formation of vesicles results. The contents of the vesicles consist of a clear liquid containing a few rete-cells and later some pus-corpuscles. In the pustular form the process is more intense in character, and the cell-emigration and multiplication increased. In the chronic forms of the disease the infiltration involves the deeper parts of the corium and even the subcutaneous tissues, which, in addition to the new connective-tissue formation sometimes taking place, gives rise to considerable thickening. The papillæ are enlarged, and at times are considerably hypertrophied, as exemplified by the so-called verrucous eczema. The exudation and cell-infiltration are especially marked along the blood-vessels. In squamous eczema the blood-vessels of the corium and papillæ are dilated, and these parts infiltrated with round cells and changed connective-tissue corpuscles. Pigmentation may take place in the deeper layers of the rete and in the corium, especially about the vessels. The pathological process in eczema seems to have its starting-point in disturbance of the capillary circulation, the origin and nature of which it is difficult to determine.

DIAGNOSIS.—It must be remembered that the disease is capable of appearing in a multitude of forms, some of which are so dissimilar in their clinical features as sometimes to occasion embarrassment in the diagnosis. No other disease except syphilis manifests itself in such a variety of forms. In all cases where the lesions are varied or where they are ill defined the eruption should be viewed as a whole, when the characters of the process will usually be apparent. Thus a variable amount of infiltration, with swelling or thickening, is almost always present, the skin being more or less red and inflammatory. Moisture or positive discharge, with slight or extensive crusting, is a frequent though by no means a constant symptom, and when present is characteristic. Itching is experienced in almost all cases, and is generally a marked symptom. In some cases heat and burning are complained of.

Cases are occasionally met with in which the eruption bears some resemblance to erysipelas and scarlatina, but the absence of systemic symptoms in eczema would prevent an error in diagnosis. Papular eczema may at times simulate the papular manifestations of urticaria, especially in children, but in ordinary cases there is no likelihood of confounding the diseases. Herpes zoster in its early stage may bear a resemblance to a patch of vesicular or papular eczema, but the grouping of the lesions and the burning or pain in the former disease will generally prove sufficient to distinguish them. Seborrhoea, especially as it occurs upon the scalp, may be mistaken for squamous eczema, but in seborrhoea the scales are greasy, containing more or less sebaceous matter, and the distribution of the disease is usually more uniform than in eczema; and, finally, in the latter affection the skin is reddish, inflamed, often thickened, and usually itchy.

Psoriasis and squamous eczema frequently simulate each other, and in some instances the resemblance is so close that error in diagnosis may readily occur. Both diseases are common, and are liable to invade all regions. In eczema the patches usually fade away into the healthy skin, whereas in psoriasis their margins are generally sharply defined. In eczema the scales are usually scanty, thin and small; in psoriasis they are abundant, whitish or silvery, large and imbricated. These points, taken in connection with the history of the case, will serve to aid in the diagnosis.

The rare disease pityriasis rubra may be confounded with squamous eczema, but the peculiar abundant, thin, papery scaling of this affection is not met with in eczema. Sometimes papular eczema resembles lichen ruber, but with attention to the characteristics of the lesions in the latter disease the diagnosis in most cases offers no difficulty. The resemblance of tinea circinata to eczema in some cases is to be borne in mind, but in the latter disease there is wanting the tendency to circular and marginate forms so characteristic of the parasitic disease. The microscope should always be employed in doubtful cases. Both tinea sycosis and sycosis may be confounded with eczema of the hairy portion of the face, but the follicular involvement in the former affections is the diagnostic point to be remembered. Scabies in its early stages often looks much like papular, vesicular, or pustular eczema, and care should in all cases be taken to make a correct diagnosis. The history of scabies, the regions involved, the distribution and multiformity of the lesions, and the presence of the parasite, as shown by the extraction of the mite or by the burrow, are all points to be duly inquired into. Eczema seldom simulates syphilis. They are most likely to be confounded one with the other when occurring in chronic forms about the scalp and the hands and feet.

PROGNOSIS.—Under favorable circumstances eczema is always a curable disease. In the prognosis of the affection as regards the probable length of time required to remove it an opinion should be guardedly expressed. It depends upon the extent of the disease, the duration, the attention the patient can give to the treatment, and the ease with which the exciting causes can be removed. Where the disease is the result of nervous prostration, as seen in those who have been mentally overworked from whatever cause, the cure will take place slowly, and many relapses will probably occur before positive recovery sets in.

Where the exciting causes cannot be entirely removed recovery is slow, and a complete or permanent cure is sometimes impossible. Thus in eczema about the hands in those who are obliged to wet or wash the parts frequently, to handle chemicals, dyestuffs, or otherwise expose the parts to the action of deleterious substances, a cure of the affection is exceedingly difficult. The same may be said in regard to eczema of the scrotum and neighboring regions, where the natural heat and moisture are constant and exciting, and to a certain extent irremovable, causes. In eczema of the lower limbs depending upon a condition of varicose veins the disease is obstinate. On the other hand, there are many cases of acute eczema met with which run a rapid course and end favorably. Eczema of the face, lips, and other exposed parts is, for evident reasons, apt to prove rebellious. In each case, then, all these points are to be taken into consideration in rendering an opinion upon the probable duration and termination of the disease.

TREATMENT.—There is no other disease of the skin which requires so thorough a knowledge of general medicine for its successful management as does eczema. The exciting cause of the affection is to be ascertained and to be properly treated. It is the specialist who has as the groundwork a comprehensive knowledge of general medicine who is best able to cope successfully with the disease under consideration. In the management of eczema both constitutional and local treatment will be necessary. It is true that some authorities depend upon external applications alone, but, judging from our own experience, a combination of external and internal treatment promises decidedly better results. In those cases in which the exciting cause has disappeared and the eczema persists from habit, as it were, the simplest local treatment may bring about a cure. But these are, unfortunately, exceptional instances. In almost all cases external treatment is indispensable.