Flashcards in Immunology - Week 4 - Fungi 2 Deck (31)
What is the primary response to a fungal infection?
Innate immunity - professional phagocytes (neutrophils, macrophages and dendritic cells) and the compliment system
What happens if the fungi escapes the innate immue system?
adaptive response through a TH1 (activate B cells to release IgG to opsonize fungi) and TH17 response (increase inflammation)
What are 4 types of superficial mycoses?
Hortaea werneckii/Exophiala werneckii
What type of fungus are Malazzesia furfur and Hortaea werneckii/exophiala werneckii?
What ype of fungus are Piedaia hortae and Tricosporon?
What is the disease caused by Malazzezia furfur?
Pityriasias (tinea) versicolor
What are the symptoms of Malazezia furfur?
small hypo or hyper pigmented macules - affected areas don't tan
(skin has that white splotchy look)
How do you diagnose Malazezia furfur?
scotch tape test - pull piece of fungi and put on slide - look for "spaghetti and meatball" like appearance
How do you treat Malazzezia furfur?
topical azoles or selenium sulfide shampoo
wide spread = oral azole treatment
What disease does Hortaea werneckii/Exophiala werneckii cause?
Symptoms: solitary irregular pigmented macule usually on PALMS OR SOLES
Treatment? topical agents: azoles and terbinafine
What can Hortaea werneckii look like?
What disease does Piedraia hortae cause?
disease: black piedra
Symptoms: hard dark nodules that surround the hair shaft
Treatment: haircut and regular hair washings - topical antifungal agents
What disease does Trichosporon cause?
disease: white piedra
symptoms: affects hair of groin and axillae - fungus surrounds hair shaft and forms white-brown swelling around hair strand
Treatment: removal of hair and topical azoles
What do you have to remove during a culture of trichosporon?
Cycloheximide - it inhibits is growth
What are three dermatophytes?
Where do dermatophytes infect?
superficial keratinized tissues (skin, hair and nails)
What are other names for dermatophytes?
Tineas or ring worm
Where do the following infect?
Tinea capitis: scalp, eyebrows, eyelashes
Tinea pedis: foot (athletes foot)
Tinea barbae: beard
Tinea corporis: smooth or glaborous skin
Tinea cruris: groin (jock itch)
Tinea unguium: nails (onychomycosis)
What are the two types of tinea capitis?
1) endothrix - arthrocondia found inside hair shaft
2) ectotrhix - arthroconidia found outside the hair shaft
3) favic (more severe)
What is one theory as to why dermatophytes only live on skin?
They are unable to grow at 37 degrees C. This prevents them from going to other areas of the body
What type of response from the host is elicited from zoophilic (from animals) or geophilic (from soil) dermatophytes?
Strong host response - highly inflamed lesions - respond well to therapy
What type of response from the host is elicited from anthropophilic dermatophytes?
Mild host response - chronic infection - difficult to cure
What are the symptoms of Tinea pedis?
itching vesicles and pustules, cracked skin, macerated, peeling, watery discharge
What are the symptoms of Tinea corporis or cruris?
tiny red pimple, actively inflamed vesicul-pustular margin and healing scaly center
What are the symptoms of Tinea capitis?
spread peripherally with patches of hair stumps
What are the symptoms of Tinea unguium?
nails will appear thickened, cracking and have a yellowish brown color
What organism do you have to be careful of when diagnosing dermatophytes?
Coccidioides resembles dermaophytes and are serious biohazard
What's a wood light and how is it used?
It's a blacklight, used to diagnose dermatophytes - some fluoresce a distinct color
What is the treatment for dermatophytes?
non-hair or nails: topical azole or terbinafine
chronic: oral antifungal