Chapter12-SkinDiseasesOVERVIEW:OCCUPATIONALSKINDISEASESDonaldJ.BirminghamThegrowthofindustry,agriculture,miningandmanufacturinghasbeenparalleledbythedevelopmentofoccupationaldiseasesoftheskin.Theearliestreportedharmfuleffectswereulcerationsoftheskinfrommetalsaltsinmining.Aspopulationsandcultureshaveexpandedtheusesofnewmaterials,newskillsandnewprocesseshaveemerged.Suchtechnologicaladvancesbroughtchangestotheworkenvironmentandduringeachperiodsomeaspectofthetechnicalchangehasimpairedworkers'health.Occupationaldiseases,ingeneralandskindiseases,inparticular,havelongbeenanunplannedby-productofindustrialachievement.FiftyyearsagointheUnitedStates,forexample,occupationaldiseasesoftheskinaccountedfornolessthan65-70%ofallreportedoccupationaldiseases.Recently,statisticscollectedbytheUnitedStatesDepartmentofLaborindicateadropinfrequencytoapproximately34%.Thisdecreasednumberofcasesissaidtohaveresultedfromincreasedautomation,fromenclosureofindustrialprocessesandfrombettereducationofmanagement,supervisorsandworkersinthepreventionofoccupationaldiseasesingeneral.Withoutdoubtsuchpreventivemeasureshavebenefitedtheworkforceinmanylargerplantswheregoodpreventiveservicesmaybeavailable,butmanypeoplearestillemployedinconditionswhichareconducivetooccupationaldiseases.Unfortunately,thereisnoaccurateassessmentofthenumberofcases,causalfactors,timelostoractualcostofoccupationalskindiseaseinmostcountries.Generalterms,suchasindustrialoroccupationaldermatitisorprofessionaleczema,areusedforoccupationalskindiseasesbutnamesrelatedbothtocauseandeffectarealsocommonlyused.Cementdermatitis,chromeholes,chloracne,fibreglassitch,oilbumpsandrubberrasharesomeexamples.Becauseofthevarietyofskinchangesinducedbyagentsorconditionsatwork,thesediseasesareappropriatelycalledoccupationaldermatoses-atermwhichincludesanyabnormalityresultingdirectlyfrom,oraggravatedby,theworkenvironment.Theskincanalsoserveasanavenueofentryforcertaintoxicantswhichcausechemicalpoisoningviapercutaneousabsorption.CutaneousDefenceFromexperienceweknowthattheskincanreacttoalargenumberofmechanical,physical,biologicalandchemicalagents,actingaloneorincombination.Despitethisvulnerability,occupationaldermatitisisnotaninevitableaccompanimentofwork.Themajorityoftheworkforcemanagestoremainfreeofdisablingoccupationalskinproblems,dueinparttotheinherentprotectionprovidedbytheskin'sdesignandfunction,andinpartduetothedailyuseofpersonalprotectivemeasuresdirectedtowardsminimizingskincontactwithknownskinhazardsattheworksite.Hopefully,theabsenceofdiseaseinthemajorityofworkersmayalsobeduetojobswhichhavebeendesignedtominimizeexposuretoconditionshazardoustotheskin.TheskinHumanskin,exceptforpalmsandsoles,isquitethinandofvariablethickness.Ithastwolayers:theepidermis(outer)anddermis(inner).Collagenandelasticcomponentsinthedermisallowittofunctionasaflexiblebarrier.Theskinprovidesauniqueshieldwhichprotectswithinlimitsagainstmechanicalforces,orpenetrationbyvariouschemicalagents.Theskinlimitswaterlossfromthebodyandguardsagainsttheeffectsofnaturalandartificiallight,heatandcold.Intactskinanditssecretionsprovideafairlyeffectivedefencezoneagainstmicro-organisms,providingmechanicalorchemicalinjurydoesnotimpairthisdefence.聽Figure12.1聽providesanillustrationoftheskinanddescriptionofitsphysiologicalfunctions.Figure12.1SchematicrepresentationoftheskinTheouterepidermallayerofdeadcells(...
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