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Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5200_Библиотеки_им_академика_М_И_Перельмана

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SpecialConsiderations
Whenchoosingtopicalorsystemictherapyinapregnantpatient,adrugincategoryBshouldbechosen overadrugincategoryCwheneverpossible.Followingisalistofcommonlyusedmedicationsforskin andskinstructureinfectionsandtheirassociatedcategories.Ofparticularnote,tigecycline,aderivative oftetracycline,is a categoryD medication andshould be avoided duringpregnancy. Ingeneral, beta­lactamsareconsideredsafeinpregnancy.  Amoxicillin–clavulanate:categoryB Cephalexinandothercephalosporins:categoryB Clindamycin:categoryB Daptomycin:categoryB Dicloxacillin:categoryB Fluoroquinolones:categoryC Vancomycin:categoryC Linezolid:categoryC Tigecycline:categoryD SMX–TMP:categoryD
MonitoringPatientResponse
Thetherapyforbacterialskinconditionsismonitoredbyfollow-upvisits(seeFigure13.1).Mostcases ofimpetigohealrapidlywithoutscarringorotheradverseeffects.Thesepatientsmaynotneedtobeseen againunlesstheconditiondoesnotresolve.However,untreatedlesionsmaylastforweeksanddevelop intoecthyma,whichisthemorechronicandsevereformofimpetigo.Thesepatientsshouldcontinuetobe followed.Folliculitis,althoughnotserious,isoftenrecurrentorchronic.Emphasisshouldbeplacedon controllingaggravatingfactorsandpromotinggoodhygienemeasures.Follow-uporreferralisrequiredif theconditionspreadsordoesnotresolve.
Patientswithcellulitisanderysipelasshouldbefollowedcloselybecauseofthepotentialforaserious systemic infection. It is sometimes necessary to change antibiotic agents or increase the duration of treatmentifthepatientfailstoimprove.Follow-uporreferralmaybenecessaryforparonychia,which oftenrecurs.
PatientEducation
DrugInformation
Patientstreatedwithsystemicantibiotictherapymustbetaughttotaketheirmedicationaroundtheclock tosustaintheproperbloodlevel.Theyalsomustunderstandtheimportanceoftakingthemedicationfor theprescribed lengthoftimeandnottodiscontinuetheir medicationeveniftheyfeeltheir infectionis resolved.
There are common side effects with most antibiotics, such as nausea, vomiting, diarrhea, and rash. Somemedicationsmustbe takenwithor withoutfood.Theseinstructionsshouldbe emphasizedtothe patient.Somemedicationsmaycausedizziness,drowsiness,orphotosensitivity, andpatientsshouldbe advisedaccordingly.
Antibiotics canpredispose a patient to fungal infections such as vaginal candidiasis or oral thrush. Patientsshouldbetoldtoreportthesesymptomssothatappropriatetreatmentcanbeimplemented.Some antibioticsmaycauseadecreasedeffectivenessoforalcontraceptives,sopatientsshouldbetoldtouse analternateformofcontraceptionwhileontheirmedicationuntiltheirnextmenstrualcycle.
Patientsshouldbe toldtoreportsignsofallergicreaction,fever,orseverediarrhea,especiallyifit contains blood, mucus, or pus. Unusual bleeding or bruising should also be reported. These adverse effectsmaybesignsofaseriousmedicationreaction.
Mosttopicalmedicationsarerelativelywelltolerated.However,someareinanalcoholbaseandare flammable.Patientsshouldavoidsmokingwhileonandshortlyafterapplyingtheirmedication.
NutritionandLifestyleChanges
Patientsneedtolearnpropermethodsofhygiene(Box13.3)topreventthespreadofinfection,secondary infection,orrecurrence.Patientswithparonychiamustbeinstructedtokeeptheirhandsdryasmuchas possible.
Incaseswhere there areopenwounds,proper woundcareinstructionisessential. Someinfections, suchasimpetigo,presentarisktoothers.Patientswithimpetigoshouldavoidcontactwithinfants,small children,olderadults,orthosewhoaredebilitatedduetothehighlycontagiousnatureoftheillness.
Althoughmostbacterialskininfectionsareself-limitingandresolvequicklywithtreatment,somehave thepotential tobecomemuchmoreserious.Patientsshouldbetaughttoreportsymptomssuchasfever, increasederythemaorstreaking,chills,ormalaisethatmayindicateaworseningoftheircondition.Also, the chronic nature of some skin infections, such as folliculitis, should be emphasized so that patients understandthattreatmentmaybelongtermandrecurrent.
Itisimportantthatpatientswithdiabeteswearproper-fittingshoestopreventulcerationandtherefore preventsubsequentinfection.Areferraltoestablishcarewithapodiatristshouldbemadeasapodiatrist canmeasureapatient’sfeetforcustom-madeshoesandinsolesandassistinfootcare.Patientsshouldbe counseled to avoid walking barefoot as that makes the foot more susceptible to injury. Additionally, patientswithdiabetesshouldhaveyearlyfootexamsandshouldbeencouragedtoself-monitortheirfeet athomewithamirror.Thisisespeciallyimportantforpatientswithdiabeticneuropathy,whomayhave decreasedsensationonthebottom oftheirfeet,making itdifficulttofeelaninjury.Amultidisciplinary teamwithvascular surgeons,podiatrists, andwoundcare specialists ishelpful inreducingthe riskof developinginfectiouswoundsthatcouldresultinamputation(Lipskyetal.,2012).
ComplementaryandAlternativeMedicine
Teatree oilcanhavesomeactivityagainstMRSA,althoughonestudyfoundittobe significantlyless effective than topical mupirocin in clearing nasal colonization of MRSA (Dryden et al., 2004). A CochranereviewonChineseherbalmedicineinthetreatmentofskinandsofttissueinfectionsfoundthat thereisnotenoughevidencetosupportitsuse(Wangetal.,2014).
Topical trypsinispossiblyeffectiveforwoundcleansingandwoundhealing.Trypsiniscontainedin someU.S.FDA–approvedproductsforwounddebridement,suchasGranulexandDermaspray.Painand burningmayoccurwiththeiruse.
FUNGALINFECTIONS
Introduction
Fungiliveinthedead,hornyouterlayeroftheskin.Theorganismspenetrateonlythestratumcorneum— thesurfacelayeroftheskin—andinfecttheskin,hair,andnails.Theycausetinea,tineaversicolor,and candidiasis.
Causes
Tinea
Dermatophytesareagroupoffungithatinfectnonviablekeratinizedcutaneoustissues.Dermatophytosis, morecommonlycalledtinea,isaconditioncausedbydermatophytes.Tineaisfurtherclassified bythe locationoftheinfection(Box13.4).
Tineacapitisprimarilyaffectschildrenofages3to9.Thisagegroupmayalsobeinfectedwithtinea corporis. Tinea pedis most commonly affects the adolescent population and young adults. Immunocompromisedpatientshaveanincreasedincidenceandmoreintractabledermatophytosis.
General factors that predispose an individual to a fungal infection include warm, moist, occluded environments; family history; and a compromised immune system. Infection is spread from people, inanimateobjects,andanimals,especiallycatsanddogs.Differenttypesofdermatophytescauseinfection onspecificsitesofthebody.Thesecommonsite-specificdermatophytesdifferbygeographiclocation. Forexample,adermatophytecausingthemajorityofcasesoftineacapitisinCanadawillnotnecessarily bethesamedermatophytecausingthemajorityoftineacapitisinfectionsinItaly.
TineaVersicolor
Tineaversicolor,also calledpityriasisversicolor,isasuperficialfungalskininfection.Itisachronic, asymptomatic infection characterized by well-demarcated, scaling patches of varied coloration, from whitishtopink,tan,orbrown.
AnovergrowthofthehyphalformofMalassezia,alipophilicfunguspartofnormalskinflora,causes tineaversicolor.Malasseziaistypicallyfoundonsebaceousareasoftheskin,wherelipid-richsebumis found.Itcauses hyper or hypopigmentation,whencertain triggers cause it toconverttoits pathogenic hyphal form. Tinea versicolor is most common in teenagers and young adults. It occurs mostly in subtropicalandtropicalareas.Intemperatezones,itismorecommoninthesummermonthsbutisseenin physicallyactive people year-round. Other riskfactors include excessive perspiration, diabetes, poor nutrition, and possibly genetics. The infection rarely causes symptoms other than discoloration, and patientsusuallyseektreatmentforcosmeticpurposes.
Box13.4 VarietiesofTineaInfections
Tineainfectionsareidentifiedbytheirlocationonthebodyasfollows:
•Head:tineacapitis
•Body:tineacorporis
•Hand:tineamanus
•Foot:tineapedis
•Groin:tineacruris
•Nails:tineaunguium(onychomycosis)
Candidiasis
Cutaneouscandidiasisisasuperficialfungalinfectionoftheskinandmucousmembranes.Itiscommonly foundinthediaperarea,oralcavity,intertriginousareas,nails,vagina,andmalegenitalia.Itcanoccurat anyageandinbothsexes.Itisclassifiedbyitslocationonthebody(Box13.5).
Cutaneous candidiasis, which is caused by Candida albicans, a yeast-like fungus, occurs on moist cutaneous sites. It thrives in occluded sites. Predisposing factors include infection, diabetes, use of systemicandtopicalcorticosteroids,andimmunosuppression.
Pathophysiology
Tinea
Dermatophytesgrowonlyonorwithinkeratinizedstructures.Mostinfectionsresultfromthreegeneraof fungi:Trichophyton,Microsporum,andEpidermophyton.Thesecanbefoundonhumans,onanimals,and inthesoil.Theyproducekeratinases,anenzymethatdigestskeratin,causingepidermalscale,thickened nails,andhairloss.
TineaVersicolor
Malasseziahasanenzymethatoxidizesfattyacidsintheskinsurfacelipids,formingdicarboxylicacids, whichinhibittyrosinaseinepidermalmelanocytesandcausehypomelanosis(lossofpigmentation).
Candidiasis
Normallyfoundontheskinandmucousmembranes,C.albicansinvadestheepidermiswhenwarm,moist conditionsprevailorwhenthereisabreakintheskinthatallowsovergrowth.
Box13.5 VarietiesofCandidiasis
Candidalinfectionsareidentifiedbytheirlocationonthebodyasfollows:
•Axillae,underpendulousbreasts,groin,interglutealfolds:intertrigo
•Glanspenis:balanitis
•Follicularpustules:candidalfolliculitis
•Nailfolds:candidalparonychia
•Mouthandtongue:oralcandidiasis(thrush)
•Areaincludedunderdiaper:diaperdermatitis
DiagnosticCriteria
Tinea
General symptomsofcutaneousfungalinfectionsincludepruritus,burning,andstingingofthescalpor skin. An inflammatory dermal reaction may cause erythema and vesicles. Diagnosis is confirmed by severalmechanisms.Onemechanismismicroscopicevaluationofthestratumcorneum.Fungiappearas rod-shapedfilamentswithbranching.
Anothermechanismfordiagnosisisfungalculture,whichcantake7to14daysforfungustogrow.This maynotbefeasibleforuseifprompttreatmentisneeded.However,giventheseverityofadverseeffects associatedwiththeuseoforalantifungals,cultureisoftenrecommendedtoselectappropriateantifungal therapyiftreatmentcanbedeferredwithoutharmtothepatient.
AthirddiagnosticmethodinvolvesusingaWoodlamp,whichproducesabrightgreenfluorescencein thepresenceofatineainfectioncausedbyMicrosporumspecies.Amajordisadvantageofthistestisthat other fungal infectionsmaybe undiagnosed because theWood lamp testidentifies only Microsporum. Anotherlimitationtothistestisthatitneedstobeperformedbyatrainedtechnician.
TineaCapitis
Presentationoftineacapitisvarieswidely.Theremaybegeneralized,diffuseseborrheicdermatitis-like scalp scaling,althoughmorecommonsignsandsymptomsinclude patches ofalopecia withor without scalypatchesorblackdots.Kerion,asevereformoftineacapitis,canberecognizedbyimpetigo-like lesionswithcrustingandredness,areasoftenderplaque,andpossiblyinflammatorynodules.Cervical lymphadenopathycanbesuggestiveoftineacapitis.Mostcasesoftineacapitisarefoundinpre-pubertal children,withadisproportionatenumberofAfricanAmericans.Itisverycontagious.Ifleftuntreated,it cancausepermanentalopeciaandscarring.
Most cases (90%) in the United States are caused by Trichophyton tonsurans (T. tonsurans).
MicrosporumcanisisthemostcommoncauseoftineacapitisinmostpartsofEurope,andTrichophyton violaceum(T.violaceum)isacommoncauseinAfricaandtheMiddleEast.
Tineacapitispresentsinseveralways:
•Inflamed,scaly,alopecicpatches,especiallyininfants
•  Diffuse scaling with multiple round areas with alopecia secondary to broken hair shafts, leaving
residualblackdots
•Graypatchtypewithround,scalyplaquesofalopecia,inwhichthehairshaftisbrokenoffclosetothe
surface
TineaCorporis
Tineacorporisiscalledringwormandaffectstheface,limbs,ortrunkbutnotthegroin,hands,orfeet. Thetypicalpresentationoftineacorporisisaring-shapedlesionwithwell-demarcatedmargins,central clearing,andascaly,erythematousborder.Itistransmittedbycontactwithinfectedanimals,humans,and objectssuchasinfectedmatsinwrestling.Transmissionviahumansislow,estimatedtobearound10% (Woo etal.,2019). TheorganismsmostcommonlyresponsibleareTrichophyton rubrum(T.rubrum), andTrichophyton mentagrophytes (T.mentagrophytes). This is commonlyseenin childrenandyoung adults.
TineaCruris
Tineacrurisisoftenreferredtoasjockitch.Itis afungalinfectionofthegroinandinguinalfolds and sometimes can spread to the upper inner thighs. The most common causes are T. rubrum and E. floccosum.Typically,thelesionbordersarewelldemarcatedandperipherallyspreading.Thelesionsare large, erythematous,andmacular, witha central clearing.Ahallmark oftinea cruris is pruritus and a burningsensation.Thereisoftenanaccompanyingfungalinfectionofthefeet.
TineaPedis
Interdigitaltineapedis,commonlycalledathlete’sfoot,ischaracterizedbyscalinganditchingintheweb spaces betweenthetoes andsometimesbymacerationoftheskin.Itis themostcommontypeoftinea pedis. Another variation is inflammatorytinea pedis,whichpresentswith vesicles involvingthemid­anterior plantar surfaceofthe foot.Athird varietyisthemoccasinstyle,whichpresentswithchronic noninflammatoryscalingandthicknessandcrackingoftheepidermisonthesole,heel,andoftenupthe sideofthefoot.Thefourthvariationistheulcerativetype.Itpresentswithvesicles,pustules,andulcers onthefoot.Itismostcommoninthosewithdiabetesoranimmunocompromisingcondition.Mostcasesof tineapedisarecausedbyT.rubrum,whichevokesaminimalinflammatoryresponse.T.mentagrophytes organismproduces vesicles andbullae. T.interdigitale andE. floccosumare also commoncauses of tineapedis.Alltypesoftineapedispresentwithitchingandburningsensation.
TineaManuum
Tineamanuumisadermatophyteinfectionofthehand.Thelesionsaremarkedbymild,diffusescalingof thepalmarskin,andvesiclesmaybegroupedonthepalmsorfingernailsinvolved.Itcancauseitching andaburningsensation.
TineaUnguium
Tinea unguium, also called onychomycosis, is a fungal infection of the nail common in older adults. Typicallyaffectedarethetoenails,whichbecomethickandscalywithsubungualdebris.Onycholysis,a separationofthenailfromthenailbed,maybeseen.Theinfectionusuallybeginsdistallyatthetipofthe toeandmovesproximallyandthroughthenailplate,producingayellowishdiscolorationandstriationsin theactualnail.Underthenail,ahyperkeratoticsubstanceaccumulatesthatliftsthenailup.Ifuntreated, thenailthickensandturnsyellowishbrown.Onychomycosisisusuallyasymptomaticbutmaybepainful whenwearingocclusivefootwear.Inimmunocompromisedpatients,tineaunguiumcanactasaportalof entryforamoreseriousinfection.
Organisms causing onychomycosis include T. interdigitale, T. rubrum, T. mentagrophytes, and sometimes C. albicans. Some health insurance plans refuse to reimburse for drug therapy without confirmationofthediagnosis.Teststhatverifythediagnosisincludethepotassiumhydroxide(KOH)test andculture.
TineaVersicolor
Skinlesionsoftineaversicolorarewell-defined,roundorovalmaculeswithanoverlayofscalesthat
maycoalescetoformlargerpatches.Theymostoftenformonthetrunk,upperarms,andneck.Theremay bemild itching.Thediagnosisisconfirmedbypositive KOHtestfindings,whichrevealbuddingyeast andhyphae.
Candidiasis
Candidiasishasseveralclassifications.Intertrigopresentsasred,moistpapulesorpustules.Itisfoundin theaxillae,inframammaryareas,groin,andskinfoldsandbetweenfingersandtoes.
Diaper dermatitis presents as erythema and edema with papular and pustular lesions, erosion, and oozing.Scalingmaybeevidentatthemarginofthelesions.
Interdigital candidiasis is an erythematous eroded area with surrounding maceration between the fingersandtoes,whereasbalanitispresentsasmultiplediscretepustulesontheglanspenisandpreputial sac.Balanitisthatinvolvesthescrotumcanbepainful.Itismostcommoninuncircumcisedmen.
Paronychiaandonychiapresentasrednessandswellingofthenailfolds.Swellingliftsthewallfrom thenailplate,causingpurulentinfection.
InitiatingDrugTherapy
Drug therapy should be initiated when the diagnosis is confirmed. For indications that require oral antifungaltherapy,itisoftenrecommendedtoobtainculturetoensurethattheselectedantifungalwillbe active against the cultured dermatophyte.This is so that the patient will not be exposedto avoidable potentialharmsinceoralantifungalsarenotwithoutrisk.ThereisablackboxwarningissuedbytheFDA recommending against the use of oral ketoconazole for the treatment of onychomycosis or cutaneous dermatophyte infectionsdue toriskof hepatotoxicity. Adiscussion oforal ketoconazole isbeyond the scopeofthischapter.
Topical agents for treating tinea versicolor include selenium sulfide, sulfur plus salicylic acid, ketoconazole, or zinc pyrithione shampoos, and azole creams. For widespread or stubborn disease, systemicitraconazolefor5daysoronceweeklyfluconazolefor2weeksmaybeprescribed.
Candidiasiscanbe preventedbykeepingintertriginousareasdrywhenpossible. Therapyshouldbe initiatedwhenclearsignsandsymptomsarepresentandaclinicaldiagnosisismade.
GoalsofDrugTherapy
Pharmacologictherapyisdirectedagainsttheoffendingfungusandthesiteofinfection.Therapyistopical orsystemic,dependingonthelocationofthelesion.Topicaltherapyisusedformostskininfections.The exceptionsaretineacapitisandtineaunguium.
Thegoaloftherapyfortineaversicolorisresolutionoflesions.Becausethelesionsarelikelytorecur inwarmweather,prophylaxisconsistsofapplyingseleniumsulfideshampootwiceamonthfor6months.
TopicalAzoleAntifungals
Topicalazoles(Table13.6)impairthesynthesisofergosterol,themainsteroloffungalcellmembranes. This allows forincreased permeabilityandleakageofcellular components,ultimatelyresultingincell death.Topicalazolesarefungicidesthatareeffectiveagainsttineacorporis,tineacruris,andtineapedis aswellascutaneouscandidiasis.Theyshouldbeappliedonceortwiceadayfor2to4weeks.Therapy
should continue for 1 week after the lesions clear. Adverse effects include pruritus, irritation, and stinging.
TopicalAllylamineAntifungals
These agentsare effective against dermatophyteinfectionsbuthavelimitedeffectivenessagainstyeast suchas candida. Patients treated with these agents may undergo a shorter treatmentperiod with less likelihoodofrelapse.Topicalallylaminesareappliedtwicedailyandincludeterbinafine,naftifine,and tolnaftate.Potentialsideeffectsincludeburningandirritation.
Griseofulvin
MechanismofAction
Griseofulvinisafungistaticthatdepositsinkeratinprecursorcells,increasingnewkeratinresistanceto fungalinvasion.
AdverseEvents
Adverse effects include nausea, vomiting, diarrhea, headache, insomnia, and photosensitivity. It is contraindicatedinhepaticimpairmentandcancausehematologicabnormalities.Thisdrugmayaggravate lupuserythematosus.
Interactions
Griseofulvin decreases levels of warfarin (Coumadin), cyclosporine (Sandimmune), and oral contraceptives. Itisimportantfor females ofreproductive agetobe placedoneffective contraceptive while on therapyas griseofulvinis pregnancycategoryX. Adisulfiram-like reactionmayoccur when takenwithalcohol.Patientsshouldbeadvisednottodrinkalcoholicbeverageswhiletakingthisdrug.
TABLE13.6
OverviewofAntifungalMedications
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