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VASCULAR REACTIONS OF THE SKINTO INJURY.

THE phenomenon of "

dermographism. " or " facti-tious urticaria " has recently been studied by ThomasLewis,l who pointed out that the " wheal-reaction "that occurs in this condition, even on light strokingof the skin, is merely an exaggerated physiologicalresponse, a similar reaction being produced on anormal skin by stronger or repeated stimuli of thesame kind. In conjunction with Ronald Grant, 2he has now published the results of experiments onthe production of wheals by means of solutions ofhistamine. It is shown first that reactions to strokeand histamine present similar time relations, and thatthe reaction consists in each case of (1) a local dilata-tion of the minute skin vessels, which, since it occurswhen the circulation has been arrested, is a primarydilatation of these vessels ; (2) a surrounding flush,due to widespread dilatation of the skin arterioles ;(3) an exudation of fluid into the tissues, the rate atwhich exudation occurs being largely governed bv therate of blood flow through the tissue. This exudationcan take place against relatively high external pressures,and is therefore not merely dependent on increasedfiltration pressure, but on increased permeability ofthe vessel wall. As a result of further ingeniousexperiments, the authors conclude that the primarylocal dilatation of small vessels is a direct effect andis independent of the nervous system, that the wide-spread dilatation of the surrounding arterioles isdependent on a local reflex, and that the increasedpermeability of the vessel wall, like the local vaso-dilatation, is uncontrolled by the nervous system.The total reaction of the skin, although complex, isidentical for both mechanical and chemical stimuli,and also in all probability for a third kind of stimulus-namely, the thermal one, which also leads to wheal-ing if sufficiently strong. It is, therefore, reasonableto suppose that with these three varieties of stimulusthere is a common factor on which the actual reactiondepends. Without discussing the experimentalevidence adduced, we may say that the authorsconclude that the wheal-reaction, whether producedin an urticarial person by stroking or in normalskins by stronger mechanical or thermal stimuli,

, is due to the liberation in the skin of a chemicalsubstance, which acts as a vaso-dilator and at thesame time increases the permeability of the vesselwall. They suggest that the same is true of thereactions produced in the skin by burns, ultra-violetlight, poisons, such as peptone, mustard-oil, andmustard-gas, certain oils and other vesicants, morphiaand atropine, and the substances introduced bybiting and stinging insects and hairy plants. It islikely that this chemical substance is histamine orsome closely allied product of tissue damage-; on theother hand, it may be that histamine, when appliedby puncture of the skin, as in the authors’ experirnents,acts like other poisons, such as morphia, and releasesthe hypothetical substance from the tissues to whichthe reaction is directly due. The researches of Daleand Laidlaw3 on the reaction produced by injectionof this substance showed that histamine causes generaldilatation of the peripheral small blood-vessels beyondthe main arterioles and an increased permeability oftheir walls, resulting in a great fall of blood pressureand collapse, a condition comparable to anaphylacticand wound shock. It has been sufficiently proved thatin secondary wound shock, and in that produced by extensive burns, it is the absorption of the productsof the damaged tissue that causes the profound fallof blood pressure and collapse. Bayliss, 4 Cannon,and others have shown that this secondary shock doesnot occur when the channels of absorption from thearea of damaged tissue are closed, and Robertson and

1 Lewis: Heart, 1924, xi., 119-140.2 Lewis and Grant : Heart, 1924, xi., 209-265.

3 Dale and Laidlaw : Jour. of Physiol., 1918-19, lii., 355-390.4 Bayliss : Intravenous Injection in Wound Shock. Longmans,

Green and Co. London. 1918.

Boyd produced a condition of shock in healthyanimals by introducing substances recovered fromburnt skin.

These researches may obviously have a veryimportant bearing on the phenomena of anaphylaxis,sensitisation, desensitisation, and immunity.With regard to anaphylaxis, it is possible that the

various symptoms that characterise the anaphylacticstate, of which an erythemato-urticarial rash is one,are directly due to the production of some histamine-like substance in the tissues, as, indeed, the work ofDale and Laidlaw, already referred to, would suggest.In this connexion it is relevant to refer to those casesin which after severe bruising without laceration of theskin or after an operation with extravasation of blood- -e.g., for removal of the breast-there may followwith an interval of about ten days an outbreak ofan erythemato-urticarial rash resembling a serumeruption. Dr. Arthur Whitfield has reported two casesof this kind in patients who had been bruised, and weknow of the condition having occurred after opera-tions. The interval between the injury or operationand the outbreak of the eruption corresponds closelywith that between the injection of a foreign serum andthe appearance of a serum-rash. It would seem likelythat in these cases some substance is produced in thedamaged tissue or extravasated blood which provokesthe eruption. The relationship of sensitisation toanaphylaxis is obscure, but, although most examplesof sensitisation cannot be regarded as truly anaphy-lactic, there would seem to be a resemblance betweenthe two conditions. It is important to recognise thatthere are two main forms of cutaneous reactionoccurring in the sensitised state, the erythemato-urticarial and the eczematous. The latter denotesepidermal sensitisation, and is well illustrated by thedermatitis provoked by poison plants and certainchemicals. Both forms of reaction, however, maycoexist in the sensitised state, and just as there arepersons who are prone to develop urticaria from avariety of causes, so there are those whose epidermisis so sensitive that the application of substanceswhich are innocuous to the normal skin produces inthem an acute eczematous reaction. A point of greatinterest is that a local sensitiveness of certain areas ofthe skin may exist, so that the sensitising substancemay provoke a reaction on one area but not on another.This question of sensitisation must be considered inconnexion with the suggestion of Lewis and Grantthat the reactions produced in the skin by the sub-stances introduced by biting and stinging insects andcertain hairy plants are actually due to some productof tissue damage. In this connexion Cranston Low6has proved that the nettle-sting gives rise to a reactionin those who have never previously been stung, andthat repeated stinging produces no immunity. It is,therefore, not a sensitisation phenomenon, but a

purely mechanical irritation from the puncture ofthe skin by the hairs on the leaf and the injection ofan irritant fluid. But in the case of biting and stinginginsects the reactions would seem to be of a differentnature. For Boycott has shown that in persons whohave never previously been bitten by the rat-fleano reaction is produced when they are bitten for thefirst time, but after repeated bitings a marked reactionoccurs, and this sensitiveness then persists. Thesame is probably true of certain stinging flies. More-over, in the case of insect-bites, unlike the nettle-sting,immunity in time is produced, and in a person whois constantly being stung by gnats and mosquitoes, orbitten by fleas and lice, eventually no local reactionresults. If the suggestion of Lewis and Grant becorrect, some explanation is required as to themeaning of this sensitisation and desensitisation.

Lastly, the question of drug-rashes may be con-sidered. In a large proportion of cases these are notspecific, and a number of different drugs may provoke..

type-reactions," such as erythema or urticaria,5 Robertson and Boyd : Jour. of Labor, and Clin. Med., 1923,

ix., 1.6 Cranston Low : Brit. Jour. Derm. and Syph., 1924, xxxvi.,

292-311.

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from the appearance of which it is impossible toincriminate any particular one. Here, perhaps, theactual cause of the eruption is not the drug itself, butsome toxic substance produced by its action on thetissues. Certain drugs, however, may evoke eruptionsas specific as those of the eruptive fevers or of thewell-defined dermatoses-for example, the halogens,and, above all, antipyrine. These specific forms ofcutaneous reaction provide one of the most fascinatingproblems not only for the clinical dermatologist butalso for the physiologist and biochemist. To take asingle example, we may cite pityriasis rosea, one

typical lesion of which is sufficient for an expert tomake a certain diagnosis ; that this disease is due toan unknown infective organism is certain, but whatare the factors on which the peculiar configuration ofthe type-lesion and the characteristic distribution ofthe eruption depend ? The morbid histology of theeruptive elements does not help us.At present we can but recognise that, among the

great variety of cutaneous reactions, some, such ascertain forms of erythema, urticaria, and eczema, are

non-specific, and these may be due not to the directaction on the skin of the various toxins that provokethem, but to substances produced by the poisonousaction of the toxins on the tissues ; on the other hand,other reactions are absolutely specific for a giventoxin, and it is on the variety of these specific reactionsthat the differential diagnosis of skin diseases largelydepends. We can recognise clinically the specialcharacteristics of this or that eruption, and in manycases a diagnosis can be made from a microscopicalsection, but at present we are absolutely ignorant ofthe physical and chemical processes that determinethe specific differences in these cuti-reactions. Itseems to us that light might be thrown on this problemby further research along the lines adopted by Lewisand Grant in their recent experiments.

Annotations.

SOCIAL SERVICES IN HOSPITALS.

" Ne quid nimis."

THE report of the Institute of Hospital Almonersfor the year 1923 gives an encouraging account of thisbranch of social service. The income and expenditureaccount shows a small balance on the right side.During the year 11 students completed the course oftraining required and received the certificate of theInstitute, eight almoners and four assistant almonerstrained by the Institute were appointed to varioushospitals, 18 candidates were accepted for training,and a fund for scholarships was placed at the disposalof the Institute. It is no light task in these days toadminister a social service department of a hospitalsuccessfully. Old landmarks have disappeared and anew generation has arisen with new needs and insistentdemands. Adaptability to these new needs is essential;the housing problem, parental responsibility, industrialfatigue, the psychology of the worker, these and manyother matters come from time to time " within the terms of reference " of the hospital almoner. The report cf the social service department of St. Thomas’sHospital for 1923 brings these points into focus froma wide angle. As the report shows, the voluntaryhospital is gradually opening its doors to a largerpublic, highly specialised forms of treatment beyondthe scope of the general practitioner tend to increasein number and complexity, special inquiries, such asthe one now proceeding in chorea and rheumatism,are opening up new fields of research, the after-careof cancer patients has become more and more a socialnecessity, and with all these advances the responsibilityof the almoner’s department increases proportionately.Added to these new developments the needs for financialinquiry, for which the almoner’s departments wereoriginally started years ago, call nowadays for especially

careful and wise handling. The " new poor " is nopolitical myth : it is the outward expression of post-warconditions which will remain with us in the voluntaryhospitals for many a long day. Although it is obviouslyimpossible to comment on the many problems whichconfront the social service departments in this con-nexion, one at least needs reference in passing-viz.,the inter-relation of the various State grants andvoluntary financial aid. The report of the Almoner’sDepartment of Moorfields Eye Hospital emphasisesthis point. State assistance has, as yet, by no meanscovered all the cases requiring help even in so well-regulated a field as ophthalmic work. Moorfieldstreats numbers of myopic children from districts ofthe Home Counties outside the L.C.C. area where thespecial education accorded to London children isimpossible to obtain owing to the scattered natureof some of the county districts. In such cases there isoften no choice between an ordinary elementary schooland a resident school for the blind, and cooperationwith the hospital social service department is neededto bridge the gap. Another instance of the dove-tailing of voluntary effort and State assistance issupplied in the condition of patients who lose theirsight between the ages of 35 and 50. These unfortu-nate patients are too old for training in workshops orother institutions under the education authorities,and too young for the State pensions for the blind,whilst the pensions of the various voluntary organisa-tions are too few to meet the circumstances. Inthese days it is obvious that patient and socialworker alike need the " infection of a good courage."

A GEOGRAPHICAL SURVEY OF HUMAN ANDBOVINE TUBERCULOSIS.

IN the United States of Am.erica the recent rapiddecline in the incidence of surgical tuberculosis inchildhood has been correlated by some authoritieswith the wholesale pasteurisation of milk which hasbeen in force for some years in certain towns. It isvery doubtful if this deduction is correct, for in certainNorwegian towns the incidence of tuberculosis inchildhood has also fallen with dramatic speed duringthe last few years, although the milk-supply of thesetowns is not pasteurised. We may not yet be in aposition to appraise accurately the importance of thebovine tubercle bacillus in the generation of humantuberculosis, but a recent statistical survey, publishedby Dr. A. Lichtenstein in Acta Pcediatrica for June 16th,would suggest that we may in the past have much over-rated the importance of bovine tuberculosis as a sourceof infection to man. Dr. Lichtenstein investigatedthe incidence of fatal tuberculosis among children1 year old and 5 years old in the towns andcounties of Sweden, comparing the figures thusobtained with the figures showing the incidence ofbovine tuberculosis throughout the country. Noconnexion whatever could be found between the twoseries of figures. In the north of Sweden, for example.bovine tuberculosis proved to be practically non-existent, whereas the death-rate from tuberculosisamong children was exceptionally high. Dr. Lichten-

stein classified the 24 counties of Sweden accordingto the frequency of bovine tuberculosis, and he foundthat the 12 worst counties in this respect showed anaverage incidence of 13-8 cases of tubercle per 10,000head of cattle, whereas the corresponding figure forthe 12 counties with the lowest rate of bovine tuber-culosis was only 2-7 per 10,000. In the first group thedeath-rate from tuberculosis among children under theage of 5 was 14-8 per 10,000, and in the second groupit was 12-7 per 10,000. The difference between thehuman rates was thus very slight in the two groupsof counties, although bovine tuberculosis was five etimes more common in one group than in the other.Dr. Lichtenstein has also compared the death-ratefrom tuberculosis among children under the age of5 with the death-rate from tuberculosis at all agesin man, and has found that these two rates runparallel to a remarkable degree in the different counties