Skin- Fungus Flashcards
What is tinea capitis
Infection of scalp eye brows, lashes Hair breaks off scalp (ectothrix) Formation of spores on hair (endothrix)
Tinea pedis characteristics
Athletes foot Agents: T mentagrophytes, T. rubrum, E. floccosum
Tinea barbae
Infection of beard Usually zoophilic T. verrucosum: cattle T. Mentagrophytes: mice, rodents
Tinea unguium
Nail infection by dermatophyte Trichophyton rubrum T. Mentagrophytes E. Floccosum
Only pathogenic species of epidermophyton
E. Floccosum
What is the cause of ringworm in skin
T. Tonsurans
Tx for sporotrichosis
Oral potassium iodide
Mycobacterium Ulcerans (buruli ulcer) vs Mycobacterium marinum
Slow growing Not pigmented Same presentation as Mycobacterium marinum
What kind of staining is needed for trichosporon
PAS
Cause of black piedra
Piedraia spp
Microsopic examination of hair
Collect misshapen, broken hair from scalp Treat with KOH
Detect mycobacteria marinum
Acid fast Yellow pigment in light requires 28-30 degrees C
Treatment of nail infections
longterm oral systemic antifungal
Fungal infections of external otitis
Aspergillus species
What other infections found with malassezia furfur
Venous catheters Seborrheic dermatitis Dandruff
Endothrix ringworm of scalp
T tonsurans
Characteristics of E. Floccosum spores
Macroconidia Smooth walled large
Presentation of white piedra
Asymptomatic growth on hair shaft White nodules easily pulled off Warm moist conditions predispose
Tinea nigra characteristics
Superficial skin infection (stratum corneum) Brow to black lesions on skin (palm/soles)
How to examine fungi (general)
PAS stain (gives fuchsin color) Silver stain (black) non fungal will be blue green Sabouraud agar for fungi
Microsporum characteristics
Attacks skin and hair, not nails
What are hyalohyphomycosis
Non black mold fungal infections Infections caused by non melanized septate, filamentous,
Chromoblastomycosis characteristics
Called verrucous dermatitis From soil Gives wart like nodules Painless NO spread of infection
Phaeohyphomycosis
Black mold have melanin containing filamentous hyphae Cutaneous/subcutaneous leseion
What is Eumycetoma
Madura foot Infection from trauma to feet, lower extremities, hands
What is tinea cruris
Jock itch T. rubrum/ e. Floccosum Usually bilateral
Mycobacterium Chelonae characteristics
Acid fast Difficult to treat
Control of white piedra
Shaving, application of antifungal agents
Ectothrix ringworm of scalp
M. Audouinii M Canis M gypseum
Trichophyton Characteristics
Attacks skin, hair, nails Life long nail infections Macroconidia smooth walled pencil shaped
Microscopic examination of superficial fungal infections of skin
Take scales from advancing border of lesion
Characteristics of Mycobacterium marinum disease
Cuts from working around sea water causes infection Chronic non healing lesions to hands, feet
What causes white piedra (superficial infection)
Trichosporon
Characteristics of Pityriasis versicolor
Superficail chronic rash Fine scaling of upper trunk and shoulders
Typical presentation of someone with sporotrichosis
Working in garden got pricks from thorns on rose, swelling on skin
What do you grow Trichophyton rubrum plate
Potato dextrose agar (red color)
What are sources of fungal infections
Anthropophilic (humans) Zoophilic (animals) Geophilic (soil)
UV examination (wood’s light) of fungi
Tinea versicolor- gold
Tinea capitis by microsporum canis and microsporum audouinii- Bright green
Tinea capitis by trichophyton- no fluorescence
What is the most common fungal agent in the USA
Pseudoallescheria boydii (petriellidium boydii)
What is the presentation of eumycetoma
Swelling leading to abcess formation and then granulomas
Black piedra characteristics
Found on shaft of hair typically those in tropics Nodules can not be pulled off
What is tinea corporis
Ringworm of upper parts of covered body Most serious chronic infection due to T rubrum
Fungal eye infections
Fusarium
Epidermophyton characteristics
Attacks skin and nail Not hair
Hortae Werneckii characteristics
Colonies smooth, oily, glistening Aged colonies- velvety Hyphae become darker with age Beach soil
Macroconidia characteristics
More numerous Rough walls spiny to warty
Tinea nigra cause
Hortae werneckii
Diagnosis of pityriasis versicolor
Microscopy for M. furfur (spaghetti and meatballs)
What causes pityrisasis versicolor
Malassezia furfur
What causes Sporotrichosis
Sporothrix schenckii Found: plants, soil, wood, moss
What predisposes people to chronic infections
Diabetes Old age Malignancy
