SUBCUTANEOUS SUBCUTANEOUS MYCOSESMYCOSES

Mary Ann C. Bunyi, MD

• Fungi reside in soil or on vegetation

• Traumatic inoculation of the skin or subcutaneous tissue

• In general, lesions become granulomatous

• Lesions usually confined to the subcutaneous tissue

Sporothrix schenkii

• Dimorphic

• Associated with grass, trees,rose bushes and other

plants

• Grows as a mold, have branches, septate hyphae and conidia

• Agent of SPOROTRICHOSIS:

chronic granulomatous infection with seondary spread to the lymphatics

Sporothrix schenkii(Morphology and Identification)

• Grows well on routine agar media

• Young colonies – blackish , shiny then wrinkles with age

• Produces branches, septate hyphae and small conidia clustered at the ends

Sporothrix schenkii(Clinical Findings)

• Conidia introduced into the skin by trauma

• Initial location of lesion is the extremity

• Initial lesion is a granulomatous nodule, eventually necroses or ulcerates

• Little systemic illness associated in immunocompetent hosts

Sporothrix schenkii(Diagnostic Tests)

A. Microscopic Examination of Specimen- histopathologic examination of tissue using routine fungal stain (Gomori’s or PAS)

B. Culture- most reliable method- Saboraud’s agar

Sporothrix schenkii(Treatment)

• Oral itraconazole – treatment of choice

• Amphotericin B – systemic disease

• Other cases, self-limited

Sporothrix schenkii(Epidemiology)

• Occurs worldwide closely associated with plants

• Predominant in males

• Higher incidence in agricultural workers

CHROMOBLASTOMYCOSIS(Chromomycosis)

• Traumatic inoculation of any of the 5 recognized agents that reside in soil and vegetation

• Phialophora verrucosa, Fonsecaea pedrosoi, Rhinocladiella aquaspersa, Fonsecaea compacta, Cladosporium carrionii

• Progressive granulomatous infection – hyperplasia of the epidermal tissue

Morphology

• Similar in pigmentation and morphology

• Colonies – compact, deep brown to black, develop velvety wrinkled surface

• Identified by their modes of conidiation

• Produce spherical brown cells termed as muriform or sclerotic or “Medlar” bodies

Phialophora verrucosa(Morphology)

• Conidia produced from flask-shaped phialides with cup-shaped collarettes

• Mature conidia accumulate around the phialide

Cladosporium carrionii(Morphology)

• Produce branching chains of conidia by distal budding

Rhinociadiella aquaspersaMorphology

• Produces lateral or terminal conidia from a lengthening conidiogenous cell

• Elliptical shaped conidia

Fonsecaea pedrosoiMorphology

• Polymorphic- phialides- chains of blastoconidia similar to cladosporium

- similar to rhinocladiella , sympodial

CHROMOBLASTOMYCOSIS(Clinical findings)

• Introduced into the skin by trauma

• Usual site of lesion: lower extremities (feet or legs)

• lesion becomes wartlike ; cauliflower-like nodules with abscesses cover the area; “ black dots” cover the warty surface

CHROMOBLASTOMYCOSIS(Diagnostic tests)

1. Microscopy - scrapings placed

in 10% KOH - detection of the

sclerotic bodies is diagnostic

2. Culture - Saboraud’s agar

with antibiotics

CHROMOBLASTOMYCOSIS(Treatment)

• surgical excision – therapy of choice for

small lesions

• Flucytosine or itraconazole – larger lesions

• Relapse - common

MYCETOMA

• Chronic infection induced by traumatic inoculation with any of the saprophytic species of fungi or actinomycetous bacteria

• Actinomycetoma – caused by actinomycetes

• Eumycetoma (Madura foot) – caused by a fungus

EUMYCETOMA

• Pseudoallescheria boydii – most common etiologic agent in US

• Madurella mycetomatis – agent which accounts for most cases worldwide

EUMYCETOMA(Clinical Findings)

• Traumatic inoculation with soil contaminated with the agent

• Lower extremities, hands and exposed areas are often involved

• Characterized by suppuration and abscess formation

• May spread to contiguous muscles

EUMYCETOMA(Diagnostic tests

• Identification of the etiologic agent is based on direct microscopis examination of the granules, culture of isolates of the agent, colonial morphology

EUMYCETOMA( Treatment)

• combined surgical and medical treatment

- management option of choice

Antifungal therapy has varied results

Disease

Agent S/Sx Identification

Sporotrichosis Sporothrix

1. Yeast

2. mold

Nodules & ulcers along lymphatics & at site of inoculation

Yeast in tissue, mold at rm temp with “rosette pattern”

chromoblastomycosis

Fonsecaea Warty nodules that become “cauliflower like appearance at inoculation

Copper colored spherical yeasts called “Medlar” or sclerotic bodies in tissue

Mycetoma

(Eumycetoma)

Madurella Draining sinus tracts at the site of inoculation

White, brown, yellow or black granules in exudates that are in fungal cultures