Subcutaneous Mycosis 06-07

Subcutaneous Mycosis

Subcutaneous Mycosis Mycetoma (Maduromycosis = Madura Foot) • Chronic granulomatous lesion of subcutaneous tissues characterized by swelling, sinus formation & suppuration. • Post-traumatic chronic infection • Common in tropical climates

Mycetoma Causes • Bacterial (Actinomycotic Mycetoma) o Actinomyces, Nocardia & Streptomyces o The granules contain very fine delicate filaments o Usually has one sinus tract

Mycetoma • Fungal (Eumycotic Mycetoma) • Saprophytic fungi like Madurella (soil organism) • Granules contain large coarse septate hyphae • Usually the lesion has many sinus openings • Causative agents • Madurella mycetomatis • Pseudallescheria boydii • Acremonium • Aspergillus

Mycetoma Clinical findings Site(s) • Feet, lower extremities, hands Findings • Abscess formation • Draining sinuses containing granules • Deformities

Mycetoma Lab Diagnosis • Characteristics of the granule & colony morphology are used for identification KOH Preparation • Bacterial : Fine branching filaments • Fungal : Coarse septated hyphae

Mycetoma Treatment • Bacterial o Antibiotics usually penicillin • Fungal o Itraconazole or o Amphotericin B  Amputation of the affected part may be needed

Subcutaneous Mycosis Sporotrichosis • Chronic infection involving cutaneous, subcutaneous and lymphatic tissues • Frequently encountered in gardeners Causative Agent Sporothrix schenckii • A dimorphic fungus living in soil & on vegetation • Spores introduced into puncture wounds (thorn pricks)

Sporotrichosis Symptoms o A chronic ulcer at wound site o Ulcerating nodules along the lymphatic drainage o Enlarged draining LN o Systemic dissemination to: o Bones, joints, meninges

Sporotrichosis

• Treatment • Cutaneous infection  Topical potassium iodide • Disseminated infection  Amphotericin B  Itraconazole

CHROMOBLASTOMYCOSIS • Posttraumatic chronic infection of subcutaneous tissue • Papules  cauliflower-like lesions on lower extremities • Causative agents 1. Fonsecaea 2. Phialophora 3. Cladosporium

LOBOMYCOSIS Causative Agent • Loboa loboi • Multiple budding yeast cells forming short chains • • • • •

Chronic, subcutaneous, progressive infection Traumatic inoculation of the fungus Hard, painless nodules on extremities Ulcerative lesions Lesions resemble those of chromoblastomycosis mycetoma and carcinoma

RHINOSPOROIDOSIS Causative agent Rhinosporidium seeberi • Has not been cultured in vitro on artificial media • Chronic infection in divers • Polypoid masses at nasal mucosa, conjunctiva, genitalia and rectum • Seropurulent discharge from nasal lesions