SUBCUTANEOUS MYCOSES

Sevtap Arikan, MD

SUBCUTANEOUS MYCOSESSporotrichosisChromoblastomycosis MycetomaRhinosporidiosisLobomycosis

SPOROTRICHOSISGeneral features

Chronic inf. involving cutaneous, subcutaneous and lymphatic tissue

Frequently encountered in gardeners May develop in otherwise healthy

individualsMost common in Mexico, endemic in

Brasil, Uruguay, South Africa

SPOROTRICHOSISCausative agent

Sporothrix schenkiiThermally dimorphicNatural habitat: soil

37°C: Round/cigar-shaped yeast cells25°C: Septate hyphae, rosette-like clusters of conidia at the tips of the conidiophores

SPOROTRICHOSISPathogenesis & Clinical FindingsSkin: Follows minor traumaNoduleulcer necrosisSkin/subcutaneous tissue lymphatic channels lymph nodes

Systemic dissemination: Bones, joints, meninges

Primary pulmonary: Chronic alcoholics

SPOROTRICHOSISDiagnosisSamples: Aspiration fluid, pus, biopsyI. Micr. Direct microscopic examination

(KOH), histopathological examination (methenamine silver stain)Yeast cells, asteroid body

II.CultureIII.Serology Yeast agglutination testIV. Sporotrichin skin test (?)

SPOROTRICHOSISTreatmentSpontaneous healing is

possible.

Cutaneous inf.: Potassium iodide (Topical/oral)

Disseminated inf.: Amphotericin B

CHROMOBLASTOMYCOSISGeneral features

Posttraumatic chronic inf. of subcutaneous tissue

Papules verrucous cauliflower-like lesions on lower extremities

Systemic invasion is very rare

CHROMOBLASTOMYCOSISCausative agents1. Fonsecaea 2. Phialophora 3. Cladosporium

Pigmented (dematiaceous) fungi in soil Arrangement and shape of the spores vary from one

genus to other

CHROMOBLASTOMYCOSISDiagnosis

Direct microscopic examination (KOH)Sclerotic body

CultureSabouraud dextrose agar, 4-6 weeks, 37°C

CHROMOBLASTOMYCOSISTREATMENTSurgeryAntifungal therapy (susceptibility

varies depending on the genus)Amphotericin BFlucytosineKetoconazole

Heat

MYCETOMA(=Maduromycosis=Madura foot)

Posttraumatic chronic inf. of subcutaneous tissue

Common in tropical climates Causative agents

Saprophytic fungi (Eumycetoma)Actinomyces (Actinomycetoma)

MYCETOMACausative agentsMadurella mycetomatis Pseudallescheria boydiiAcremonium Exophiala jeanselmeiLeptosphaeriaAspergillusActinomyces

MYCETOMAClinical findings

Site(s): Feet, lower extremities, hands

Findings: Abscess formation, draining sinuses containing granules Deformities

Dissemination: Muscles and bones

MYCETOMADiagnosis

Clinical findings are nonspecific

Identification of the infecting fungus is difficult

Characteristics of the granule, colony morphology, and physiological tests are used for identification

EUMYCETOMATreatment

SurgeryAntifungal therapy

Amphotericin BFlucytosineTopical nystatin Topical potassium iodide(choice of treatment varies according to the infecting fungus)

RHINOSPORIDIOSISGeneral & Clinical featuresChronic inf.In diversPolypoid masses at nasal mucosa,

conjunctiva, genitalia and rectumSeropurulent discharge from nasal

lesions

RHINOSPORIDIOSISCausative agent

Rhinosporidium seeberiNatural reservoir: fish, aquatic

insects Spherules filled with endospores (in

tissue) Has not been cultured in vitro on

artificial media

RHINOSPORIDIOSISTreatmentSurgery

Ethylstilbamidine(Local injection)

LOBOMYCOSISPathogenesis & Clinical features

Chronic, subcutaneous, progressive inf. Traumatic inoculation of the fungusNatural inf.: in dolphinsHard, painless nodules on extremities,

face and earVerrucous / ulcerative lesionsLesions mimic those of

chromoblastomycosis, mycetoma and carcinoma

LOBOMYCOSISCausative agent

Loboa loboiMultiple budding yeast cells

forming short chains Asteroid body

Has not been cultured in vitro on artificial media

LOBOMYCOSISTreatment

Surgery

ClofazimineAmphotericin BSulphonamides