Cutaneous Fungi Flashcards
Where are the two places that superficial mycoses take place on the body?
Stratum corneum of skin
Cuticle of hair
Where are the places the epidermophyton (dermatophyte) likes to infect?
Lower limbs and torso
Is there an inflammatory reactions with superficial mycoses? What is the primary concern with superficial mycoses?
No—Cosmetic concern
Pityriasis versicolor (tinea versicolor) is caused by what?
Malassezia furfur (pityrosporum orbiculare)
Is Malassezia furfur dimorphic? Normal flora?
yes
Malassezia furfur is usually found where on the body?
Its lipophilic, so sebaceous glands
What are the causative factors of pityriasis versicolor?
More sebaceous secretions
What are the symptoms of Malassezia furfur infection?
Scaly patches yellow-brown to dark brown in color
How do you diagnose Malassezie furfur infx?
Direct observation of skin scrapings with KOH prep
“spaghetti and meatballs”
Spaghetti and meatball morphology = ?
Malassezie furfur (Pityriasis versicolor)
What is the treatment for Pityriasis versicolor?
Topical treatment of keratolytic agents
Topical azoles
Tinea nigra is caused by what?
Exophiala Werneckii infection
Is Exophiala Werneckii dimorphic? What form is in the body?
dimorphic, with yeast like form in the body
Where, geographically, are Exophiala Werneckii infections found?
warm coastal regions
How is tinea nigra transmitted?
Constant contact with the organism (wood, compost)
What are the symptoms of tinea nigra? How does this occur?
Light brown-black, oval shaped lesions over the hands and feet
Produces melanin
How do you diagnose Tinea nigra?
KOH treated scrapings and seeing thick walled septate hyphae containing dark pigment
What is the treatment for tinea nigra?
topical stuffs
What are the species that cause black and white piedra?
Black = piedra hortae White = Trichosporin beiglii
Where, geographicaly are white ad black pidera found?
Black = tropics White = Temperate and semi tropical
How are black/white piedra transmitted?
soil and compost or animals
What is the clinical syndrome of black piedra?
Hard, gritty nodules on hair/scalp firmly attached to hair. Cause a metallic sound when combing hair
What is the clinical syndrome of white piedra?
Fluffy/soft/white nodules on pubic/facial/axillary hair
loosely attached to hair
How do you diagnose black/white pedira?
Microscopic examination of hair
What is the treatment for piedra?
Shaving hair off, hygeine
Cutaneous mycoses are caused by a group of fungi collectively known as what? What do they utilize for nutrition?
Dermatophytes–utilize keratin as a nutrient source
What are the three genera of dermatophytes? What do they all have in common?
Microsporum
Trichophyton
Epidermophyton
All are capable of degrading and utilizing keratin
How are dermatophytes transmitted?
Geophilic (soil)
Zoophilic (animals)
Anthropophilic (people)
What are the predisposing factors for dermatophytes?
Closed toed shoes, community showers
What is the clinical syndrome of dermatophytes?
Circular lesions–“ringworm”.
Itching
Clinical manifestations of dermatophyte infection are referred to as what? Are these indicative of the species?
Tinea (blank)
No correlation between species names
What is tinea pedis?
Athletes foot
What is the presentation of tinea pedis?
Lesions of the foot
Scaliness of foot
What is tinea corporis?
Ring worm
How does tinea corporis present?
Red, round, scaly patch with a raised border, usually on the trunk
Pustules
What is tinea capitus? Symptoms?
Scalp infections
Scaly lesions
Patches of hair loss
What is FAVUS?
Mass of hyphal elements surround the base of a hair shaft in tinea capitis
What is tinea cruris? Symptoms?
Jock itch
Erythematous area around the groin
What is tinea unguium-(onychomycosis)? Symptoms?
Nail infections
Dry/cracked toenails
Hyperkeratosis and discoloration
How do you diagnose tinea infections? (2)
KOH prep and see hyphae (to confirm fungi)
Woods lamp (green fluorescence)
What is the Woods lamp helpful for?
Determining lesions on the scalp are fungi via fluorescence
How do you treat dermatophyte infections?
Application of topical azoles
What is the drug used for tinea capitis?
Griseofulvin
How do you treat tinea unguium?
oral antifungals for a long time
Candida infectious form = what form? Environmental?
Yeast in environment
Hyphal forms in tissue
Candida albicans is normal flora. What predisposes it to infection (beside immunosuppression)?
Open-ish, wet areas.
What are the cutaneous infections associated with candida?
Diaper rash
Dishwasher hands
What are the symptoms of cutaneous candidiasis?
Papules or confluent plaques that are red and TTP
Chronic mucocutaneous candidiasis is associated with what? (2)
T cell deficits
Endocrine disorders
Where on the body are chronic mucocutaneous candidiasis found?
Mouth
Face
Fingernails
What is the usual immune response to chronic mucocutaneous candidiasis?
Granuloma
What are the three major predisposing factors to disseminated candidiasis?
- Increase in colonization
- Breakdown of normal physical barriers
- Immunosuppression
Treatment for systemic candidiasis?
Amp B
What are subcutaneous mycoses? How are subcutaneous mycoses transmitted?
Fungal infections of the dermis
Acquired through trauma of the skin
What is sporotrichosis? Cause?
Infections of cutaneous, sub and lymph by Sporothrix schenckii
Sporothrix schenckii is dimorphic? What is the form it takes in tissue?
Yes–yeast in tissue
How is Sporothrix schenckii (sporotrichosis) transmitted?
traumatic inoculation of plant surfaces (thorns, splinters etc)
What are the symptoms of Sporothrix schenckii infx (sporotrichosis)?
Inflammation at site of inoculation followed by painless granulomas up the lymph tract
How do you diagnose sporotrichosis? What is specific about how it grows?
Cultivation in tissue or pus
Mold converts to yeast at 37 C
What is the treatment for sporotrichosis?
Oral KI/azoles
What is the causative agent of chromoblastomycosis?
Chromomycosis
Where, geographically, is Chromomycosis found?
Tropics
What are the symptoms of Chromomycosis?
Painless, darkly pigmented cauliflower lesions
How do you diagnose Chromomycosis?
Brown pigment hyphae in skin scrapings
Medlar bodies
Medlar bodies (copper colored pennies) = ?
Chromomycosis
What is the treatment for Chromomycosis?
Surgical removal of lesions
5-fluorocytosine
What is mycetoma?
Madura foot
Chronic subcutaneous infections of the foot
What are the three common species that cause Mycetoma?
Madurella mycetomatis
M. grisea
Pseudallescheria boydii
What are the symptoms of mycetoma?
Slow growing papule
Ulcerating lesions with pus
Bone involvement
How do you diagnose Mycetoma?
Grain in pus, tissues, or discharge
Culture
How do you treat Mycetoma?
Amputation
Colored grains in pus = ?
Mycetoma