Medical Microbiology

&Tineacorporis(ringworm):MicrosporumcanisandTrichophytonmenta-

grophytes.Affectshairlessskin.

&Tineapedis(athlete’sfoot):T.rubrum,T.mentagrophytes,andEpidermo-

phytonfloccosum.Affectsmainlythelowerlegs.

&Tineacapitis:T.tonsuransandM.canis.Affectsscalphair.

&Tineabarbae:T.rubrumandT.mentagrophytes.Beardringworm.

&Tineaunguium:T.rubrum,T.mentagrophytes,andE.floccosum.

&Onychomycosis(nailmycosis):VariousdermatophytesandCandidaspp.

Diagnosis.Materialsuitablefordiagnosticanalysisincludeskinandnail

scrapingsandinfectedhair.Thefungiareobservedunderthemicroscope

inaKOHpreparation.Identificationisbasedonthemorphologyofthehy-

phaeaswellasonthemacroconidiaandmicroconidiainthefungalcultures.

Therapy.Dermatomycosescanbetreatedwithlocallyappliedantimycotic

agents.Incasesofmassiveinfectionsofthehair,andaboveallofthenails,

theoralallylamineterbinafineorazolescanbeused.Griseofulvinisrarely

usedtoday.

Epidemiologyandprevention.Dermatophytesoccurnaturallyalloverthe

world.Thegeophilicdermatophyte,M.gypseum,cancauseinfectionsinper-

sonsinconstant,intensivecontactwiththesoil(e.g.,gardeners).Prophylactic

measuresforalldermatomycosesconsistinavoidingdirectcontactwiththe

pathogen.Regulardisinfectionofshowersandwardrobescancontributeto

preventionofathlete’sfoot,averyfrequentinfection.

OtherCutaneousMycoses

Pityriasis(ortinea)versicolorisasurfaceinfectionoftheskincausedby

Malasseziafurfur.Thisinfectionisobservedmainlyinthetropicsbutis

knownallovertheworld.Itcauseshypopigmentations.M.furfurisdepen-

dentforitsmetabolicneedsonasourceoflong-chainfattyacids.Thisfungus

isactuallyacomponentoftheskin’snormalflora.Thepathogenesisofthe

infectionshasnotyetbeenclarified.

Tineanigra,whichoccursmainlyinthetropics,iscausedbyExophiala

werneckii.Infectionresultsinbrowntoblack,maculousefflorescenceson

theskin.

WhiteandblackpiedrasisaninfectionofthehaircausedbyTrichosporon

beigeliiorPiedraiahortae.

374 6 FungiasHumanPathogens

6

Kayser, Medical Microbiology © 2005 Thieme