ECZEMA (Gr. EKE a, a cutaneous eruption)  , one of the most common and important of all skin diseases, consisting of a catarrhal inflammation of the skin originating without visible external irritation, and characterized in some stage of its evolution by a serous exudation . This definition excludes all those forms of inflammation of the skin (dermatitis), which though they may be identical in course and manifestation are yet caused by chemical or mechanical irritants . For an attack of eczema two conditions are necessary: a predisposition or special irritability of the skin, and a directly exciting cause . The first of these conditions is usually inherited or depends on some underlying constitutional state . Thus any organic lesion which may produce oedema and malnutrition of the cutis and epidermis as in kidney diseases, any condition of imperfect metabolism as in dyspepsia or malnutrition, or seborrhoea, may be the predisposing cause . Another influence that has received increasing attention from skin specialists is that of any nervous shock or prolonged mental strain . A " chill " is followed in most people by an ordinary cold, but in some by an attack of eczema . Again, it may be caused by reflex nervous irritation from the uterus, stomach, &c . In some women it always accompanies menstruation, and in others pregnancy . It is of common occurrence in infancy, being attributed by some specialists to dentition, but by others to seborrhoea . Also there is an undoubted relationship between eczema and certain forms of functional neurosis, 0f which perhaps asthma is the most striking illustration, some physicians considering the latter trouble to be eczema of the bronchial tubes . Sufferers from rheumatism and gout are also specially prone to eczema, though the exact relationship is a much disputed point .

There are yet other cases that are undoubtedly microbic, but the micro-organism cannot produce the lesion unless the

soil is suitable . As a rule it is net contagious, though when complicated by micro-organisms it may be auto-inoculable, or more rarely inoculable from one patient to another . Except between the ages of ten and twenty years when menstruation is becoming established, and again at the menopause, males are more liable to be attacked than females . In old age the sex influence is lost . An attack of eczema is usually described as acute or chronic, but the only distinction lies in the greater or less intensity of the inflammation at the time of description: it has nothing to do with the length of time that the disease has lasted . The illness usually begins with a feeling of itching and burning at the site of the lesion . The skin becomes covered with an erythematous blush, on which numerous tiny vesicles form . Swelling, heat, redness and tension are all present . The vesicles grow larger, run together, and either burst or are broken by the patient's scratching, a clear fluid exuding which stiffens linen . The discharge does not dry up at once, but continues to exude—hence the name of " weeping eczema " when this is a prominent symptom . In mild cases the symptoms begin to subside in a few days, the exudation growing less and scales and scabs forming, under which new skin is formed . But where the attack is more acute fresh crops of vesicles spring up and the process repeats itself .

In some cases papules are the predominant lesions, but in others, especially when the

face is attacked, the erythematous condition is more marked . A severe attack of eczema is usually accompanied by some slight constitutional disturbance, but the general health seldom suffers appreciably, unless, as occasionally, the itching is so bad as to make sleep impossible . The irritation and local heat may be out of all proportion to visible changes in the skin, and in neurotic patients the nervous excitement may be extreme . The attack may centre itself on any part of the body, but there are certain places where it more usually begins, such as the bends of the elbows, the backs of the knees and the groins; the groove behind the ears, the scalp, the palms or the soles, and the breasts of women . According to its position the form of the eczema is somewhat modified . On the front of the legs and arms, from the uniform redness it exhibits in these positions, it is known as eczema rubrum . On the scalp it is generally of the seborrhoeic type, and in children; especially when pediculi are present, it will become pustular from microbic infection . On the palms and soles it brings about a thickening of the epidermis which leads to the formation of cracks, and is hence called eczema rimosum . The disease can best be treated by a combination of internal and external remedies . Internally, when the inflammation is acute, nothing is so good as antimony, since this relieves the arterial tension and thus reduces the local inflammation . But this must never be given when the patient is suffering from depression . In other cases, especially for babies and children, small doses of calomel are very beneficial; strychnine, phosphorus and ergot are all useful at times .

When nervous excitement is marked it must be treated with sedatives .

Arsenic and iron are both contra-indicated in this disease, since they increase blood formation and hence stimulate the eczematous process . Internal treatment is always best when combined with local treatment, but as a preliminary to this all crusts and scales must first be removed to allow the remedy free access to the disease . Locally the aim is (r) to overcome any source of irritation, (2) to protect the inflamed surface from the air and from microbic infection, and (3) to relieve the itching . The diet should be simple but nourishing, and all hygienic precautions must be taken .