export_sst fungal infections Flashcards
Four superficial fungal infections
Pityriasis versicolor
Tinea nigra
Black piedra
White piedra
Pityariasis versicolor causative agent
Malassezia furfur
Malassezia furfur features
Dimorphic
Part of normal flora
Lipophilic
Pityriasis vericolor symptoms
Numerous, irregularly shaped scaly patches
Yellow-brown to dark brown in color
Hyper or hypo-pigmentation
Diagnose pityriasis versicolor
Direct observation of skin scrapings
KOH prep - “spaghetti and meatballs”
Treat pityriasis versicolor
Topical treatment with keratolytic agents or azoles
Tinea nigra causative agent
Exophiala werneckii
Exophiala werneckii features
Dimorphic
Tinea nigra symptoms
Distinct oval-shaped lesions on hands and feet
Light-brown to black in color - organism produces melanin
Diagnose tinea nigra
Skin scrapings (KOH) reveal two-celled yeast forms with dark pigment
Treat tinea nigra
Topical treatments with keratolytic agents or azoles
Black piedra causative agent
Piedra hortae
White piedra causative agent
Trichosporon beigelii
Black piedra presentation
Nodules composed of asci and ascospores (sexual process)
White piedra
Mycelium and anthroconidia forming a collar around the hair shaft
Common location for black piedra
Primarily scalp
Nodules firmly attached
Common location for white piedra
Pubic, axillary, beards, eyebrows
Loosely attached
Diagnose either piedra
Microscopic examination of hair
Treat either piedra
Shaving hair and good hygeine
Group of organisms that cause cutaneous mycoses
Dermatophytes
Three genus’ that cause cutaneous mycoses
Microsporum
Trichophyton
Epidermophyton
Tinea pedis
Athlete’s foot
Tinea corporis
Ring worm
Most common on the trunk
Tinea capitis
Scalp infection
Patches of hair loss
Favus
Favus
Mass of hyphal elements surrounding the base of the hair shaft
Tinea cruris
“Jock itch”
Lesions in the groin, most common in men
Tinea unguium
Onychomycosis
Infection of nail plate and nail bed
Hyperkeratosis and discoloration
Diagnose dermatophytic infections
Direct observation of fungal elements in skin scrapings, nail, or hair samples
Woods lamp
Used to examine lesions on scalp or beard
Many fungi will fluoresce
Treat dermatophyte infections
Application of exfoliating agents as well as topical azoles
Specific treatment for tinea capitis
Griseofulvin
Treatment for tinea unguium
Very difficult to treat
Long term administration of oral antifungals
Cutaneous candidiasis presentation
Papules or confluent plaques
Redness, tenderness, and cracking
Chronic mucocutaneous candidiasis
Superficial infections at mouth, face, and fingernails
Immunosuppressed
Subcutaneous fungal organisms
Sporotrichosis
Chromoblastomycosis
Mycetoma
Sporotrichosis causative agent
Sporothrix schenckii
Sporothrix schenkii features
Dimorphic
Induced through traumatic inoculation
Sporotrichosis clinical presentation
Inflammation at inoculation site
Painless granulomatous lesions
Lesion ulcerates, developing along the draining lymphatic tract
Diagnose sporotrichosis
Cultivation from tissue or pus
Treat sporotrichosis
Oral K+ iodide
Oral azoles
Chromoblastomycosis clinical presentation
Initially a wart-like lesion
Slowly develops into a red/gray cauliflower-like lesion
Painless
Diagnose chromoblastomycosis
Brown-pigmented hyphae Medlar bodies (copper-colored spherical cells)
Treat chromoblastomycosis
Surgical removal of lesions
Oral antifungals
Mycetoma disease
Madura foot
Mycetoma causative agents
Soil-inhabiting fungi
Madurella mycetomatis
Madurella grisea
Pseudallescheria boydii
Mycetoma clinical presentation
Initially a slow growing papule at site of inoculation
Lesion ulcerates, releasing pus, blood, and discharge
Underlying bone becomes involved, resulting in pitted lesions