Eczema is derived from a Greek word meaning "to boil". The term is descriptive of the acute stage of the process when the skin is covered with small blisters, like bubbles on boiling water. The blisters which are formed within the epidermis break readily (except on the hands and feet where they are preserved by the thick horny layer, and the names cheiropompholyx and podopompholyx have been given to this type of eczema) resulting in copious weeping from a denuded, raw surface followed by crusting as the exudate dries, and often complicated by secondary infection of bacterial, fungal or viral origin. In the later stages the eruption is dry and is characterized by redness, scaling and cracking consequent upon the disordered growth of the epidermis.; and these changes persist until a healthy horny layer has reformed. Thickening of the skin occurs as a result of cellular infiltration and oedema in the dermis, and it is much increased by compulsive scratching and by rubbing of the itchy skin until a leathery texture is produced known as lichenification. At all stages of eczema patients complain that the lesions itch.
Eczema is not a disease but a reaction pattern in the epidermis1 which can be precipitated by many stimuli. It follows that the causative agents must be identified and neutralized if the eczema reaction is to subside. The pattern is not necessarily fully developed in every case. Thus one may speak of a " wet " eczema, where the early stages of the process predominate, and of a " dry " eczema at a later stage. A single, unrepeated eczema-producing stimulus—for example contact of a sensitized skin with a leaf of primula obconica—will result in an inevitable and relentless chain of events consisting of itch and erythema for a few hours, blisters and weeping for a few days, and scaling for about three or four weeks, by which time—barring the occurrence of lichenification as a result of the patient's own interference—the skin will have healed except, perhaps, for some residual staining. This erstwhile inexorable result of a single unrepeated stimulus can nowadays be suppressed by the use of corticosteroid preparations which can be used during the normal three or four weeks required for healing, without interfering with the healing process. Consequently, provided that the stimulus is not repeated, this treatment will appear to have " cured " the patient; but if, as is usual, the stimulus continues, a relapse will follow when it is stopped.
The treatment of eczema consists first in identifying and eliminating the provocative stimuli, and second in calming down the inflamed skin until the natural healing process has had time to occur. Since unfortunately the former aim. is sometimes unattainable, the latter must perforce on these occasions suffice. The provocative stimuli are now considered. From their diversity it will be apparent that a thorough investigation of eczema is bound to involve a full history and examination, such as are required in any medical case, but with particular attention directed towards the external environment.
PROVOCATIVE STIMULI
External Irritants.—Primary irritants such as strong acids and alkalis many oils, paraffin, turpentine, petrol, soap, and many antiseptics, will irritate any skin if allowed to come into contact with it in high enough concentration for a sufficient time. The effect is enhanced by removal of the natural greasy protective covering of the skin such as occurs in housewives, nurses, charwomen and metal turners who are habitually using detergents. Allergenic irritants such as primula obconica, chrome, nickel, penicillin, paraphenylenediamine, etc., will in time produce a state of allergic hypersensitivity in certain skins which will then react to the irritant in high or in low concentration. Their identification is often exceedingly difficult since, as far as the patient is concerned, they are harmless (for example cosmetics, flowers, clothing, footwear, ointments, etc.) and it seldom occurs to the patient to suspect such commonplace things. Their recognition depends upon raising the possibility, combined with. Considering
1 For practical purposes eczema is synonymous with dermatitis though dermatitis is used in a general way to describe dermal as well as epidermal inflammation, as in dermatitis herpetiformis. Eczema is to be preferred when a specifically epidermal reaction is implied.
The pattern of the eruption: 'footwear, for example, causes air eczema which primarily involves the feet although the eruption may spread later to other skin which has never been in direct contact with the irritant by a process of auto-sensitivity. These secondary lesions are called by dermatologists the " ide " eruptions and are regarded as allergic complications effected by a humoral mechanism. The ide eruptions are extremely important as they sometimes dominate the clinical picture. Thus it is possible for a patient to present with oedema of the eyelids, or with eczema of the ante-cubital fossae which is an ide reaction resulting from nickel sensitivity induced by metal suspender clips ; it is even possible for only one out of the four clips to produce a mild eczema at the site of primary contact with nickel—so mild that the patient, having merely noticed the mark, has dismissed it as of no account. There are so many potential irritants, that one can only describe the common patterns of eruption produced.
In the face the skin of the eyelids is especially sensitive, and oedema and itching is usual. Things that obviously touch the face should be considered first such as cosmetics, washing materials, handkerchiefs, spectacles, and local applications, whether for the skin or the eye. Secondly there are things that are brought into contact with the face indirectly, being carried thence on the hands and fingers by the unconscious habit of rubbing the face. These include plant juices such as primula and chrysanthemum, nail varnish, hair dye, antibiotics, antiseptics, red or green ink from ball-point pens, etc. The seasonal incidence of many horticultural allergens helps to identify them. Thirdly, as already mentioned, the possibility of an ide eruption from some other primary focus such as nickel sensitivity or a " varicose " eczema must be considered.
On the hands the skin is much less reactive than it is on the face because of the thicker horny layer. Many of the irritants affecting the hands are of the primary irritant variety, and are associated with the degreasing effects of detergents and the macerating effects of water. Housewives and charwomen are particularly liable to this kind of trouble. A state of allergic hypersensitivity is often added ; this applies for example to an antiseptic, rubber, turpentine, or to a pharmaceutical preparation applied locally—especially local anaesthetics and antihistamines. Other occupations hazardous in this respect include baking (flour, sugar, fats, flavourings), engineering (oils, greases, paraffin, diesel, petrol), building (cement, diesel), and working on railways (diesel, chromate). So much detail about the occupational causes of eczema has been collected that special works which deal entirely with occupational skin diseases are available for reference. The mere distribution of the eruption will sometimes reveal the causative irritant, as between the fingers from holding a pen ; in the palm of one hand where an orange has been held, between the fingers where the juice has trickled, and on the thumb and forefinger of the opposite hand which did the peeling ; on one finger from a rubber finger protector ; on the backs of the fingers of one hand from going into a handbag.
On the feet, as on the hands, the skin is tough. Irritants will affect the thinner skin on the dorsum and on the instep, before the horny areas of the sole. The chief hazard is footwear which contains many potential irritants including formalin, dyes, adhesives, rubber and chrome. Potentially irritant footwear or clothing can sometimes be worn for months with impunity until either a soaking or sweating can precipitate an acute contact eczema.
On the trunk and limbs, nickel sensitivity is confined initially to the areas of contact of nickel containing metals with the skin, such as suspender clips, brassiere buckles, watch strap buckles, zip fasteners and ear-rings. An ide eruption on the face and forearms commonly accompanies nickel sensitivity. Clothing sensitivity often due to dye or formalin produces patterns depending on the nature of the offending garment, and the degree to which the skin is protected by the remainder of the clothing. For example, the underclothes protect the parts that they cover from an irritant shirt; and a short-sleeved blouse will protect all but the forearms from an irritant jersey. Irritant clothing in direct contact with the trunk tends to affect the friction areas—the axillary folds, the belt line and the buttocks—initially. Clothing which is not irritant in itself can become irritant by being washed in a detergent to which the patient's skin is sensitive.
On the neck there may be a localized irritation from the collar, from a necklace or its clasp, from a hairnet (involving the ears and brow as well), from a clothing tab, and so on.
All patterns of contact eczema should conform to the following criteria : the eruption should begin on a piece of skin that has been in close contact with the supposed irritant; its removal should result in clearance of the eczema; its re-introduction should provoke a relapse; a patch test using it, suitably diluted, should be positive. This last condition is hedged about with qualifications connected with the practical difficulties of doing and interpreting patch tests, and the advice of a dermatologist is desirable.
The bizarre histories sometimes associated with contact eczema are due to intermittent contact with the irritant. A suit, a scent, a handkerchief or a soap may be used only occasionally resulting in a series of remissions and relapses of the original eczema, and here a diary is important to record the dates of the recurrences. The amount of an irritant required to provoke a relapse may be very small; for example in a case of hypersensitivity to an antihistamine cream, the patient's convalescence was interrupted by a severe exacerbation of the eruption at one wrist due to wearing for one hour a raincoat which she had worn at the beginning of her illness. Although there was no visible stain at the wrist there must have been enough of the cream present to provoke an exacerbation. This garment had been overlooked when carrying out the injunction to have everything cleaned that could possibly contain a trace of the cream.
The management of a case of contact eczema consists in preventing contact between the offending substance and the patient's skin by removing it from the patient's environment, or by removing the patient from its vicinity. This advice sometimes implies a change of work. For those who cannot change their work, such as housewives, protection combined with the suppressive effect of corti-costeroid applications is a second best choice. Barrier creams are not very satisfactory, and protection of the hands with rubber gloves which must be worn over very thin cotton ones (clumsy as this may be) is the best choice, together with measures designed to reduce contact with water and detergents to a minimum.
Infections.—There are several ways in which infection can occur as a complication of eczema. Most commonly the eczematous area becomes secondarily infected ; the original lesion is thus perpetuated or there may be an exacerbation of the eruption. The most dramatic occurrence of this sort is seen when eczema, usually infantile eczema, becomes secondarily infected with the virus of vaccinia or of herpes simplex—a condition known as Kaposi's varicelli-form eruption. The risk of this complication explains why babies suffering from eczema should not be vaccinated. Much more usual, and more insidious, is the growth of bacteria or yeasts which takes place on any area of eczematous skin. In addition to causing persistence of the eruption, this supra-infection can change its appearance as a result of hypersensitivity to the products of infection. An example of this is the eczema of coal miners. This begins locally with a traumatic eruption arising from the friction of coal dust but with the development of an ide eruption—the consequence of secondary infection—the lesion changes into a widespread post-traumatic infective eczema. Primary infection of the skirt, especially tinea of the feet, can give rise to eczematous ide eruptions such as eheiropompholyx. The part played by infection in seborrhoeic eczema is important, but it is not clear whether the infection or some constitutional abnormality is the primary factor. It is certain that anti-infective local measures are required in its treatment. A focus of extra-cutaneous infection such as septic teeth, tonsils, gall bladder, etc., is rarely responsible for producing or maintaining eczema.
The treatment of an infection residing on the skin is to apply anti-infective agents either topically or systemically or both, but always in conjunction with the routine treatment for eczema. When the severity or the extent of the infection makes oral antibiotics advisable a bacteriological diagnosis should be made. While the report on the bacterial flora is awaited it may be justifiable to give oxytetracycline, 0.5 g. twice daily, modifying the antibiotic treatment in the light of advice received from the bacteriologist. Sulphonamides have a place in . oral treatment but none for local use, since sensitization to these drugs can cause a chronic and disabling dermatosis precipitated by exposure to sunlight and tending to recur every summer. For local use the brightly coloured dyes work very well against a wide variety of organisms, but they have assthetic disadvantages : thev are crystal violet paint B.N.F., and a solution of eosin in water, ½ per cent. Magenta paint B.P.C. should be diluted with one to four volumes of water before being applied to an acutely inflamed skin. All are useful when large areas of skin have to be treated, especially with flexural eruptions. A thin layer of these dyes carefully applied is fully effective, and when used in this way the treatment is much less messy and inconvenient. Mild silver proteinate, B.P.C. is a non-sensitizing mild antiseptic useful for adding to calamine liniment in ¼ per cent. strength. Cleaner alternatives are the detergent hexachlorophene which is useful for washing the skin in the presence of infection, and the chemical or antibiotic agents chlorhydroxyquinoline (in the form of quinolor compound ointment), iodochlorhydroxyquinoline ointment, polynoxylin ointment or paste, and chlortetracycline, neomycin, bacitracin, framycetin and gramicidin. These should be prescribed, singly or in combination, together with corticosteroids. At the time of writing, preparations of this kind are not listed in the National Formulary but there are many proprietary preparations to choose from. No anti-infective agents are free from the possibility of causing sensitization, and neomycin does so in a rather insidious manner which may escape notice ; the patient does not complain of an acute exacerbation of dermatitis but merely that the ointment has lost its effect. Patch tests to neomycin carried out on normal skin are likely to be negative unless the skin has been " stripped " with cellophane tape first. Lesions caused by yeasts are amenable to treatment with dyes, nystatin ointment, or the organic mercurial, penotrane. Viral infection can be treated only by measures directed against the secondary invaders. Until a reliable anti-viral agent is available for general use, very severe cases of Kaposi's eruption should be given an injection of immune globulin. Such treatment carries a risk of transmitting serum hepatitis, but if the patient's life is in danger it is clearly justifiable to accept this risk. Tar has a place in the treatment of seborrhceic eczema and post-traumatic infective eczema.
Ingesta.—Ingestion of a drug to which the patient's skin has been sensitized —such as penicillin or the sulphonamides—may result in a recurrence of the original eruption. More difficult to trace is the drug that is taken in non-medical form, such as quinine in tonic water. Food allergies that affect the skin usually produce urticaria but can provoke eczema, especially in hypersensitive (" atopic ") subjects. The intelligent co-operation of the patient or his parents is essential in order to identify the allergen.; A diary must be kept as an essential preliminary to skin testing. Careful records relating to diet, drugs and other possible sources of allergens must be kept. Further it must be remembered that unless the test solutions are of suitable concentration for the purpose the results may be misleading. Once the offending allergen has been identified, the patient must be advised to stop ingesting it.
Inhalants.—Inhalation of allergens, particularly house dust and pollens, will exacerbate some cases of atopic eczema. The patient does not necessarily complain of sneezing or a running nose. The most obvious preventive measure consists in minimizing exposure to household dust. Old-fashioned methods of sweeping which create dust should be abandoned in favour of vacuum cleaners. In some patients desensitization may be effective.
Physical Factors.—Eczema that is provoked by light can be due to previous contact with photosensitizing substances such as tar, the sulphonamides and many plant juices, but more often it is idiopathic. Occasionally the condition is associated with an abnormal porphyrin metabolism. Complete avoidance of sunlight is burdensome. It necessitates changing to night work ; but partial avoidance of sunlight combined jwith local application of corticosteroids to suppress the eczema, a light " screen " (such as 10 per cent. phenyl salicylate in soft yellow paraffin, or Uvistat) to protect the skin and the empirical use of chloroquine phosphate by mouth (0-35 to 0-5 g. daily) usually suffices. Chloroquine should be reserved for occasional use only, as prolonged courses of treatment may cause blurred vision (interference with accommodation), giddiness or rarely permanent damage to the sight.
Heat provokes recurrences of eczema. It probably acts by causing retention of sweat in glands whose ducts have not fully recovered from eczema, although there may be no visible abnormality of the skin. Sweating predisposes to exacerbations of latent fungus infection and can precipitate an ide eruption. It also makes for more intimate and prolonged contact of the clothes with the skin, and this aids the transfer of irritants from the clothing to the skin. Patients convalescing from eczema should be given ample time to recover before returning to hot jobs or hot climates ; and patients subject to eczema should be encouraged to keep their skins dry and cool.
Moisture, particularly when combined with heat, encourages organisms to flourish on the skin. Prolonged maceration of the skin is tantamount to non-specific trauma ; it also makes the skin much more penetrable by chemical substances. The damage opens the way for an infective eczema. Wet work usually upsets the skins of those prone to eczema, but on the other hand soap and water used in moderation should not be prohibited in eczema unless it manifestly does harm, which seldom happens. A plain, unscented toilet soap is usually satisfactory but for those who cannot tolerate soap there are substitute available.
Cold weather causes chapping of the skin, particularly in ichthyotit and atopic subjects, which can start an infective eczema. Protection from the weather is important, but the atopic skin is usually intolerant to contact witt wool. The use of an ointment containing equal parts of glycerin of starch and ol salicylic acid ointment B.P. is a valuable prophylactic. A useful hand lotion is made up thus : glycerin 60 ml., compound tincture of benzoin 8 ml., a sufficiency of oil of rose and gum acacia, water to 170 ml.
Emotions.—It is debatable whether emotional upsets by themselves can cause eczema, but it is certain that they can potentiate many of the stimuli already mentioned. Under emotional stress the threshold of reaction to allergens can be lowered. Cosmetics, handkerchiefs and sedative drugs are in demand ; sweating is increased ; and, any itchy spot will be rubbed vigorously. Such conditions favour the aggravation and persistence of any form of eczema, and the lesion tends to become lichenified from rubbing. Patients with atopic eczema in particular are liable to exacerbations when under emotional stress. The management of the emotional situation demands measures appropriate to the individual patient; and the routine symptomatic treatment of the eczema is also required.
Metabolic Deficiency.—Deficiency of food rarely affects the skin unless there is a frank vitamin deficiency. Malabsorption from the gut is sometimes associated with eczema. The common form of metabolic disturbance of the skin is secondary to venous stasis in the legs, the result of damage to the deep veins. The chronically raised venous pressure causes oedema and interferes with the nutrition of the skin which then becomes liable to ulceration and eczema. Treatment consists in facilitating venous return by applying external pressure with a web bandage or by using elastoplast applied over zinc paste bandage. When recumbent, the patient should be encouraged to lie with the legs raised. If palliative measures fail, a surgical opinion should be obtained. If these methods are employed the eczema will look after itself, provided there are no other provocative stimuli such as infection. Eczema, the result of stasis, is particularly liable to be complicated by an ide eruption, either as a result of auto-sensitivity or sensitivity to a local application. In either case attention should be directed primarily to the leg—even though this may not be the site of the main part of the eruption.
Heredity.—The atopic constitution which is manifested by the occurrence of infantile eczema, Besnier's prurigo, asthma, hay fever, migraine and urticaria in succeeding generations of certain families, and sometimes by several of these diseases occurring successively or consecutively in one individual, is the basis of much chronic disability from skin trouble. Apart from the classical presentation with lichenified eczema of the antecubital fossae and the popliteal fossae there are many clinical variations, the worst of which involve almost the whole skin in what can only be described as chronic pruritic misery. Rigours of both the physical and emotional climate in which these patients live have a bad effect on their skins. Their treatment follows the same principles as those which apply to other cases of eczema ; but special care should be taken in tracing allergic, climatic and emotional stimuli, and in viewing the patient as a whole person. In the worst cases there is a place for oral corticosteroid treatment. The rare hereditary disease phenylketonuria is sometimes accompanied by infantile eczema. If the urine of all infants suffering from eczema were routinely tested with ferric chloride, the correct diagnosis would be obvious ; and this would be the preliminary to giving these infants the appropriate diet.
SYMPTOMATIC TREATMENT
Corticosteroids.—The introduction of the corticosteroid drugs has revolutionized the treatment of eczema, and it has also thrown into relief the part played by secondary infection. Eczema of all kinds will be suppressed by corticosteroid drugs locally applied. If a favourable response is not obtained the following possible explanations should be considered :
The skin may be too horny for the drug to penetrate the epidermis. The best response is seen where the skin is thin, for example on the face. Penetration can be aided by using an occlusive dressing such as plastic film but, if used on extensive areas and over long periods, this method carries some risk of systemic absorption.
Secondary infection may be interfering with the response. This would be an indication for using an anti-infective agent.
Contact factors may still be operating, for example an irritant cosmetic or a soap.
The corticosteroids for local application vary in their efficacy. Thus betamethasone valerate and fluocinolone acetonide are more effective than 2½ per cent. hydrocortisone which in turn is more effective than i per cent. hydro-cortisone.
The preparation being used may be potentially irritating. For example an incorporated anti-infective agent may cause irritation or the vehicle (such as an ointment base) may be responsible. Sensitivity to neomycin is often overlooked. The corticosteroid drugs used for local application do not cause irritation but by-products in their manufacture may, and traces of these have been known to give trouble. Unexplained irritation from a corticosteroid preparation should be reported to the manufacturer.
The patient may be fostering the eruption by neglecting the treatment, by deliberate interference or unwittingly by compulsive rubbing.
If none of these causes of failure apply, a different preparation should be tried. It is not practicable to list those available in order of potency, nor is it necessary since the question is largely theoretical; but there is general agreement that triamcinolone was more effective than its predecessors, and that fluocinolone and betamethasone are better still.
The various corticosteroids are available in several pharmaceutical preparations for dermatological treatment. These are made up as ointments (greasy), creams (non-greasy), lotions (suitable for moist areas) and sprays (easy to apply to large areas), and they are available with or without added anti-infective agents. It is desirable to have as standard one preparation and to prescribe that routinely, say betamethasone valerate or fluocinolone acetonide. They are normally prescribed as the ointment, but a cream and a lotion are available, the latter being indicated when treating any wet surface. When an added anti-infective agent is required, it is wise to depend on one preparation —say iodochlorhydroxyquinoline—and to change to some other preparation only if this is necessary.
The need for an anti-infective drug is by no means always obvious from the naked eye appearance of the eruption. Nevertheless the enhanced response that can often be obtained from such treatment supports the view that infection plays a much more important part in eczema than is commonly suspected. With a basic schedule of this kind the physician learns to recognize the expected response, and varies the treatment only when the results fall short of expectation. If the usual routine fails, he may choose a different anti-infective agent, a combination of agents or a more potent corticosteroid, according to the needs of the situation. Flexural eruptions—particularly those in the ano-genital region—are liable to possess a rich bacterial flora often including yeasts, and in this situation a combination of nystatin with another antibiotic or the use of one of the dyes may be conspicuously successful after a routine method has failed. There will be . occasions when the area to be treated is so extensive that giving the corti-costeroids bv mouth is more economical. Oral administration, however, especially over a long period of time carries the risk of undesirable side-effects.
Other Methods.—The impact made by the' corticosteroid drugs is too recent for their use to have been fully integrated with the older forms of treatment. It is dear though that many of the old prescriptions will be retained, not for sentimental reasons but because they are useful. The corticosteroids : produce their best results on thin skin such as that of the face and genital region, and they are least effective on the hands and feet although they can be made to | work in these places by plastic film occlusion. They are entirely suppressive ^ in their action and unless the eczema has had time and opportunity to heal s during the course of their application it will relapse at the end of treatment. The cost of corticosteroids must, of course, be considered but not without due regard to their unique action and great usefulness.
Acute weeping eczema is best treated by using wet dressings ; for example ½ per cent. of silver nitrate, 5 per cent. strong solution of lead subacetate or 1.5 per cent. aluminium acetate solution, in water. When secondary infection is present 5 per cent. to 10 per cent. of ichthammol in water should be used, corn- bined with oral antibiotics if there is lymphangitis, fever or toxaemia. An alternative procedure applicable to the hands and feet is to soak the affected skin; in a solution of potassium permanganate, i in 6,000, or in weak iodine solution B.P., I in 50 in water, every four to six hours and to keep the area wrapped in a j clean towel between the soakings.
Lassar's paste contains starch 24 parts, zinc oxide 24, salicylic acid 2, soft yellow paraffin 50. The salicylic acid is best omitted. Lassar's paste is a | particularly useful preparation which seldom irritates the skin, adheres to it gently but firmly and has a soothing effect. It is a satisfactory application for the | hands and feet which are often intolerant to more greasy preparations. It will: not deal with infections; these require anti-infective treatment—such as one of the dyes painted on the skin—before the paste is applied on top. It can be used as a vehicle for active medicaments such as tar. It is undesirable tc try to remove every trace of the old paste before applying it anew because clings so hard that its complete removal is difficult without damaging the skiri. .Once a day is usually quite often enough to change the dressings. The paste is very satisfactory to use after wet dressings have dried up a weeping eczema, and have left the skin dry and tending to crack.
Ichthammol paste is much thinner than Lassar's paste and, whereas Lassar's paste must be spread, ichthammol paste can be rubbed provided that the ares to be treated is not hairy. It contains i per cent. of ichthammol and 15 per cent of zinc oxide in soft yellow paraffin. To provide full protection it should be spread on to material such as calico and bandaged into position.
Calamine liniment is semi-liquid and can be spread easily over large areas, or used as wet dressings. It consists of 8 per cent of calamine and 6 per cent. of lanoline in a base consisting of equal parts of linseed oil and lime water. Ichthammol can be added, from i to 5 per cent. if desired, but since a few patients are sensitive to ichthammol it is safer to use the plain liniment unless the mild antiseptic action of ichthammol is required. Mild silver proteinate B.P.C. in ¼ per cent. strength is another suitable antiseptic agent to add.
Crude coal tar has a great healing action in eczema. Fortunately it is not appreciably carcinogenic in man when used therapeutically, although prolonged occupational contact with tar does lead to cancer of the skin. It can be applied in zinc paste from i to 10 per cent. in strength or painted on in its crude state as a varnish using a paint brush, allowed to dry and powdered with unscented talc. To avoid shaving hairy areas it can be diluted—12 g. of crude coal tar, 20 ml. of benzene and 90 ml. of acetone. It is not a particularly clean application; and purified tars, though cleaner, are less effective. Tar should be applied in the later stages of eczema as it may cause irritation in the early, acute stage; patients suffering from nummular eczema and seborrhceic eczema, however, usually tolerate tar well from a remarkably early stage. It is always advisable when using tar to make the first application to a limited area in case the skin proves to be sensitive to it. It should also be remembered that tar makes the skin photosensitive.
Occlnsive Bandaging is particularly suitable for the limbs. Its success depends upon the protection and rest that it affords and provided that the occlusion does not encourage any infection which may be present, and that there are no internal provocative stimuli, the eczema will heal. The most comfortable occlusive dressing is a zinc gelatine bandage. This is not easily prepared. Further its application calls for some skill: it must be painted on in successive layers and built up on a gauze bandage, the zinc gelatine being heated before use to ensure that it is of the correct consistence. The proprietary paste bandages which are ready for application are a serviceable substitute and the best are those that harden least during wear. All require careful application to avoid lumpiness and to achieve the correct tension or else friction sores will develop where the bandage rubs the skin. The bandage is kept in place for a period of from three days to six weeks according to the needs of the individual patient: it is best to change the dressing infrequently—so long as the patient remains comfortable. Medicaments such as ichthammol and tar can be incorporated in the bandage to produce a greater healing effect. In an apprehensive patient corticosteroids can be applied to the skin before the first application of the bandage to make the initial stage more comfortable. It should be remembered that many patients are often very alarmed at the thought of their limb being occluded, and their anxiety often becomes manifest as an increase of irritation. Hence this method of treatment, though useful, should never be regarded as a matter of routine.
X-rays have been used extensively in treating chronic eczema. There are many alternative applications, and it would seem wiser to avoid radiotherapy as much as possible but it is a valuable standby in very resistant cases.
Internal treatment, apart from corticosteroids, consists of the use of sedatives —either barbiturates (such as amylobarbitone) or antihistamines (such as promethazine hydrochloride) or both. In the treatment of eczema the anti- histamines are not used to block the actions of histamine but for their sedative and tranquillizing properties. No drug will relieve itch specifically and the treatment of itch in eczema is always the treatment of the eczema itself.
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