The pustular form of eczema differs from the vesicular, simply in the larger proportion of leucocytes contained in the exudation. The pustules form on a reddened patch, break, and give issue to the exudation which, drying, forms somewhat greenish crusts. On removal of these a raw surface becomes visible. After an indefinite period the exudation diminishes and disappears, and a dry and desquamating surface replaces the previous moist condition. After a time the desquamation ceases, and the skin returns to a healthy state.

Between the forms just mentioned there may be any number of gradations, simply characterized by the greater or less proportion of leucocytes contained in the discharge, and this would appear to depend on the constitution of the patient and his own peculiar pyogenic proclivities.

In the papular form of eczema the exudation is less watery, and instead of reaching the surface and forming vesicles or pustules, produces little solid elevations which are usually not so closely aggregated, at least, in the beginning, as the lesions already mentioned; they are also slower of formation, and having once appeared, persist for a much longer time than the vesicles or pustules. As the itching which accompanies the eruption leads to scratching, the little papules become torn, and a small amount of fluid exudes, which dries into thin crusts. After some weeks or months, as the case may be, the tendency to papulation ceases, the skin becomes drier and more scaly, until finally every trace of lesion disappears.

In the fissured form we find little clefts in the epidermis giving issue to a usually slight amount of serous or sero-purulent exudation. Thin crusts may form and continue until there is a gradual resumption of the healthy condition through the same changes as in the other forms.

There is still another way in which an acute eczema may commence. As the exudation gradually reaches the surface the stratum corneum becomes loosened, and almost imperceptibly exfoliates,* or is rubbed off by the patient in his efforts to calm the accompanying irritation. This results in a humid and exuding surface, with the rete cells naked and exposed. Crusts form, and the eruption passes through the same stages as in the other forms. The dry and scaly condition, present in all forms prior to recovery, is usually termed the third stage.

The varieties of eczema depending on the character of the primitive lesion have received certain special appellations, as Eczema vesiculosum, pustulosum, papulatum and fissum or rimosum. In addition I have ventured to apply the specific appellation of nndosum to the form last de-scribed. Besides these we have names indicating the condition of the eruption, as Eczema humidum and siccum, and other names referring to the locality occupied, as capitis, manuum, etc.

The location of the eczematous eruption, to a certain extent influences its aspect. Thus, on the head the exudation glues the hairs together, and forms much thicker crusts than elsewhere, and in the eczema capitis children small abscesses of the scalp are not infrequent, and the lymphatic glands at the back of the neck become enlarged and somewhat ten-der. Pediculi also appear to exhibit a preference for the eczematous scalp of a child.

When eczema involves the region of the mustache and beard in adult males, the inflammation sometimes dips down into the hair-follicles and excites a condition usually included under the name of Sycosis or Men-tagra.+ The prominent peculiarity of this form is the appearance of little pustules surrounding the mouths of the hair-follicles. The hairs become loosened, and if extracted with the forceps frequently bring with them their root-sheaths which form a cylindrical investment to the hair-root.

On the palmar and plantar surfaces the fissured and vesicular forms are most commonly met with. Owing, however, to the greater relative thick-ness of the stratum corneum in these regions, it does not rupture so easily, but the back pressure of the exudation dissects it up to a greater or less extent, and we consequently have much larger vesicles than are met with elsewhere.

The patches of eczema may vary in number and in size; occasionally the greater, and practically the entire surface may be involved. Whatever its extent, pruritus is one of its prominent accompaniments, and the aspect of the eruption may be more or less modified by the existence of scratch-marks in addition to the lesions peculiar to the disease itself.

Having considered the acute forms, we pass to the chronic. Chronic eczema may be an affection that has commenced acutely, but on reaching the second or third stage may persist in one or the other of these conditions for an indefinite period; or, on the other hand, the early stages may be absent and the eruption commence as a subacute affection chararacterized at its beginning by a slightly reddened, slightly elevated, sometimes roughened or papulated patch, and covered with fine, non-imbricated scales. These patches are. usually small and circumscribed, rarely attaining the extent frequently met with in the other forms. The peculiar feature, that, besides chronicity, usually characterizes long-standing cases of eczema, is the presence of more or less infiltration. This may be a uniform circumscribed thickening of the skin upon which the special lesions repose, or the surfsce may be rendered rough and uneven by the occurrence of papules and fissures. Sometimes the papillae of the corium undergo considerable hypertrophy and give the thickened patch a somewhat warty aspect. Occasionally both the papillae and other portions of the derma, more especially in the neighborhood of the ankles, participate in the proliferation of new tissue to an extent that may cause the affection to simulate Elephantiasis.

* I have elsewhere < 87, 148) more fully considered this condition, which is not gen-erally alluded to in work* on dermatology.

+ It is to be distinguished from a parasitic disease of these Darts which will be 1ater described under the name of Trichophytosis barbae.

The various conditions above described may persist indefinitely, sometimes undergoing spontaneous recovery, though not, as a rule, if there be any marked degree of infiltration, or any proliferation of new tissue.

Among the most annoying features of eczema is the tendency to relapse. Whether a case recovers spontaneously or is cured by treatment, there is no guarantee that it will not, in a few weeks or months, return as severely as before, that is to say, if the causes which produced the first attack remain in operation.

The pruritus that accompanies all forms to a greater or less degree is sometimes so severe as to interfere with the patient's rest at night, leading ultimately to decided nervous prostration.

Eczema may occur in persons presenting all grades of general health; in those who otherwise appear strong and hearty, and in those who are enfeebled by various causes.

Diagnosis

The experienced eye rarely has any difficulty in detecting eczema in any of its varied phases. Occasionally, however, it is difficult to say whether a chronic superficial congestion should be considered an eczema that has halted in the first stage, or a simple erythema. Occasionally, also, a red infiltrated patch with large scales may closely simulate a psoriasis, or one with small scales, pityriasis. In either case if the resemblances are so close that an absolute diagnosis cannot be made, it is of little consequence, as the treatment would be essentially the same. In certain locations, however, it is important to be strictly on the guard in the matter of diagnosis; thus a scaly eczema of the scalp might very closely resemble a partly cured favus or trichophytosis, so on the face, an eczema barbae might be mistaken for trichophytosis. In these cases the microscope would enable the diagnosis to be made without difficulty. The palmar and plantar surfaces in chronic eczema sometimes present appearances that may greatly resemble syphilitic lesions of the same parts.

Prognosis

The prognosis of eczema varies greatly in different cases. In acute eczemata the prognosis is almost always extremely good, for, as a rule, you can assure the patient that his trouble can be relieved within a reasonable period. In some of the chronic forms, however, especially if there be much long-standing infiltration, the prognosis should be more guarded, and no definite assurances should be given to the patient as to the the me that will probably elapse before he is cured. He should further be warned that during treatment that appears to be progressing favorably, he is liable at any time to temporary aggravations, sometimes traceable to indiscretions on his own part, but, also very often corning on without assignable cause. The eczemata that are, perhaps, among the most obstinate are the chronic infiltrated ones of the scrotum.

Etiology

Eczema is undoubtedly due, in the writer's judgment, to the blood condition resulting from imperfect assimilation of the food and deficient oxidation of the protein compounds existing in the blood, a point fully discussed in connection with the rheumic diathesis (p. 126). This is, par excellence, the predisposing cause. The exciting causes, however, are various. Thus in infants the use of acrid and too alkaline soaps may produce irritation that precipitates an outbreak. In older children an invasion of lice may do the same. In adult males a tender skin, a dull razor, and an unskilful barber furnish the necessary etiological factors. In certain avocations the contact with acrid substances, and in certain persons the application of a flaxseed or a mustard poultice will bring out the eruption. On the lower extremities a very frequent cause of eczema is the existence of varicose veins. In these cases the cutaneous circulation becomes sluggish, the vitality of the tissues lowered, and the integument of the part ready to yield to the slightest morbific tendency. The possible connection in some cases between varicose veins and pressure on the vena cava inferior by an enlarged liver should not be overlooked.

Certain other external sources of irritation may lead to an outbreak of eczema, as, for instance, vaccination, or an attack of scabies or phthi-riasis. In other words, in persons predisposed to eczema, almost any irritating agency may be sufficient to invite and localize the eruption, while in others the impulse seems to come wholly from within, as the most careful inquiry may fail to elicit any probable external etiological agency.