Micro 02 - Superficial Mycoses

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Superficial mycoses are limited to these parts of the body: non-living tissues such as skin and hair
Cutaneous mycoses are found in these parts of the body: skin, scalp, nails

invade and persist in living tissue
Subcutaneous mycoses are found in these parts of the body: deeper infections that are mostly limited in scope to the skin, muscles, fascia
Factors that limit SCS mycoses:: 1. innate resistance to fungal infections
-cellular, not humoral
2. fatty acid content
3. pH = fungi like acid
4. cellular turnover
5. normal bacterial flora
6. limited iron content
_______ immunity controls fungal infection: Cellular
Cellular immunity against Fungi: -PRR domain proteins like __1__ -__2__: 1. Card9

2. Toll-like receptors
How are Superficial mycoses diagnosed?: Direct Observation and culture
Do superficial mycoses elicit an immune response?: NO
Superficial mycoses includes things like...(3): Pitryiasis versicolor
White and Black Piedra
Tinea Nigra
Pityriasis versicolor is caused by this yeast: Malassezia furfur
Properties of Malassezia furfur: Often asymptomatic
Normal flora
Colonizes kids soon after birth
Pityriasis Versicolor is in this part of the skin: Strateum Corneum
Malassezia furfur is _________: lipophilic
-requires special medium
Malassezia furfur is often in the __1__ or areas rich in __2__: 1. Torso
2. Sebaceous glands
Pityriasis Versicolor: -sometimes seen around __1__ -can cause infections around indwelling __2__ -infections can be __3__ -most often in __4__ or in __5__: 1. puberty
2. catheter
3. widespread
4. tropics
5. summer
Pityriasis Versicolor: -related to fungi that cause __1__ on grain crops: Bunt or Smut
Diagnosis of Pityriasis Versicolor: 'spaghetti and meatballs' appearance of the organism in KOH cleared specimen
DOC's for Pityriasis Versicolor *ineffective drug?: Fluconazole or Itraconazole

*Terbinafine
Drug recommended for Pityriasis Versicolor in patients with catheter infections: Amphotericin B
Topical treatments that may be considered for Pityriasis Versicolor: Selenium or dandruff shampoo
Tinea Nigra etiologic agent: Exophiala Werneckii
Tinea Nigra most often occurs on this part of the body: Palms or soles
Tinea Nigra can be confused with these things: Melanoma
Moles
Benign pigmentation
Places where Tinea Nigra are usually seen: South or Latin America
Africa
Tinea Nigra is limited to this part of the skin: Strateum Corneum

*no inflammation*
Tinea Nigra appearance in KOH cleared tissue: abundant dark branched septate hyphae from 1.5-5 micrometers in diameter
Tinea Nigra grow on this agar: Sabourauds glucose at 30'C

*they are mucoid colonies
*become dark green to black with time
Tinea nigra treatment: topical antifungal applied for 2-4 weeks

*can be surgically removed or systemic antifungals
Black Piedra etiologic agent: Piedra Hortae
Describe Black Piedra: -superficial hair infection

-nodules on hair of head are SEXUAL fruiting bodies and contain Ascospores
Most frequently infected area of body with Black Piedra: __1__ Most cases are __2__ and may remain so for __3__: 1. scalp hair
2. asymptomatic
3. years
Diagnosis of Black Piedra: Direct Observation

Culture
Black Piedra treatment: shaving or clipping hair

Topical or Oral Azoles
Terbinafine
White Piedra etiological agent: Trichosporon Beigelii
Describe White Piedra infection: Superficial hair infection
Trichosporon is a normal member of the flora of these body sites: Mouth
skin
nails
A ______ bacterial infection can be present along with Trichosporon (White Piedra): Coryneform
White piedra affects these animals in addition to humans: Horses and monkeys
Taxonomy of White Piedra: Basidiomycete, related to Cryptococcus
Clinical significance of White Piedra: IC'ed hosts at risk to develop invasive infection
-lungs
-kidneys
-spleen
White Piedra are more often seen on these hairs: Pubic or Axillary hairs
Treatment of White Piedra: Shaving or Clipping hair
Oral Itraconazole
One case of disseminated White Piedra infection was reported as having been treated with _________: Capsofungin
Cutaneous Mycoses infect ______ tissue and elicit ______: Living tissue

immune response
Cutaneous mycoses are often called__________: Dermatophytes
3 prominent genera of Cutaneous Mycoses: Epidermophyton

Trichophyton

Microsporum
All cutaneous mycoses are ________: Mitosporic Ascomycetes

*mitosporic = reproduce by mitosis, asexual
Cutaneous Mycoses includes these clinical infections Severity of infection is related to ________: Athletes Foot
Onychomycosis
Ringworm (=Tinea)

Immune status of the host
Tinea corporis = 1 Tinea Capitis = 2 Tinea Cruris = 3 Tinea Barbae = 4 Tinea Pedis = 5 Tinea unguium = 6: 1. body ringworm
2. scalp
3. jock itch
4. beard
5. athletes foot
6. onychomycosis/nails
Term for Dermatophyte fungi associated with humans: Anthrophilic
How is Tinea diagnosed?: Visualization of fungi in specimen

Lesion characteristics
List the 3 Zoophilic Tinea: -Microsporum canis
-Trichophyton mentagrophytes var Metnagrophytes
-Trichophyton verrucosum
Explain the significance of the Woods lamp: Fluorescence does indicate the presence of Fungi, but lack of fluorescence does not indicate absence of fungi
Most common fungal complaint?: Tinea Pedis (athletes foot)
DOC's for Tinea Pedis 1. Simple cases 2. More effective approach 3. Moccasin infections: 1. topical Allylamines, Azoles

2. Terbinafine applied 2X daily

3. Oral Terbinifine or Itraconazole for widespread or prolonged infection
Tinea corporis occurs on this part of the skin: relatively HAIR-LESS
What distinguishes Tinea Corporis from a Superficial infection: Tinea corporis causes an immune response
Transmittance of Tinea Corporis: by pets or from infected people (sharing shoulder pads)
DOC's for Tinea Corporis 1. for few lesions 2. Widespread infection: 1. Topical

2. Oral
-Terbinifine
-Itraconazole
-Fluconazole
-Griseofulvin
Tinea cruris = ?: Jock itch
Dermatophytes that cause Tinea Cruris (4): 1. Epidermophyton floccosum
2. Microsporum canis
3. Trichophyton mentagrophytes
4. Trichophyton rubrum
If the scrotum is involved in Tinea Cruris, this fungus is involved: Candida
Tinea Capitis involves these parts of the body: scalp
hair
Tinea capitis is most common in these people: pre-pubescent blacks
Tinea capitis DOC's: Oral
-Griseofulvin
-Terbinafine
-Itraconazole
-Fluconazole

*topical not effective b/c drug cannot penetrate into the follicle
This is not useful in diagnosing Tinea Capitis: Wood lamp
Tinea Barbae are caused by ___________ How do you tell the difference between fungal and bacterial infection?: Zoophilic Dermatophytes = most common in Farm-workers

Plucking hairs is painless in Tinea Barbae, but painful in bacterial infection
Tinea Barbae treatment: ORAL
-Itraconazole
-Terbinafine

*oral b/c infection is deep in follicle
Onychomycosis is sometimes called _______: Tinea Unguium (a subset)

*T. Unguium is caused by Dermatophyte fungi
*Onychomycosis can also be caused by yeast or other molds
Onychomycosis is more common in these people: Men
Elderly
Diabetics

*seen in 2-3% of the pop.
Most common form of Onychomycosis and its agent: Distal and Lateral Subungual Onychomycosis (DLSO)

Dermatophyte fungi
-Trychophyton
-Epidermophyton
-Microsporum
DOC's for Onychomycosis: Lamisil - oral 6-12 wks
Sporanox - oral, pulse dosing
-1 week on, 3 off for 5 months
Griseofulvin
Loprox (tea tree oil)
Downfall of Lamisil (Terbinifine): some Hepatocytoxicity
Downfall of Sporanox (Itraconazole): Hepatotoxicity
Congestive heart failure
Cutaneous mycoses can also include ___________: mucocutaneous candidiasis
Mucocutaneous Candidiasis is a _______ infection of men and women -it is in the _____ of all mammals: yeast

GI tract
Way to diagnose Mucutaneous Candidiasis of the vagina: Candida in WET MOUNT of vaginal smear
DOC's vaginal candidiasis: Clotrimazole cream/tablets

Oral Fluconazole
Orophayngeal Candidiasis is more common in these people: Nursing babies

AIDS
DOC's for AIDS Oropharyngeal Candidiasis: Lozenges of Clotrimazole or Nystatin
How are Subcutaneous Mycoses infections usually obtained?: following trauma
Subcutaneous Mycoses infections characteristics: -can be life threatening (difficult to treat)
-grow thru tissue and cause surface lesions
-usually follow trauma
-course of infection often many years
-considered rare and exotic in USA
-infect otherwise healthy people
How are Sporotrichosis infections often acquired?: puncture wound (rose thorn)
Sporotrichosis is associated with __1__, and outbreaks among __2__ workers: 1. sphagnum moss

2. nursery
Sporotrichosis follows the _____ that drain the site of inoculation: Lymphatic glands
-lymph nodes are usually not involved
Sporotrichnosis: -lesions sometimes mimic __1__ -sometimes called "__2__": 1. Blastomycosis

2. rose gardener's thumb
How is Sporotrichosis diagnosed?: -pattern of infection

-culture from tissue at 30'C, dimorphism is demonstrated by switching culture to 37'C
Treatment of Sporotrichosis (3): -ORAL SATURATED POTASSIUM IODIDE
-Itraconazole for subcutaneous disease
-AmphotericinB for disseminated
Describe Chromoblastomycosis lesions: chronic warty/verrucous nodules of epithelial tissue overgrowth caused by abnormal # and arrangement of cells
What initiates Chromoblastomycosis lesions? How much do they grow per year?: trauma

~2 mm/year = very slow growing
How is diagnosis of Chromoblastomycosis made?: Examination of Clnical Material
-Sclerotic cells or "Medlar bodies" are characteristic
Chromoblastomycosis are caused by a variety of __1__ fungi that are found in these places: __2__: 1. dematiaceous = dark hyphae

2. soil, decaying vegetation, rotting wood, forest carpets
Common fungi causing Chromoblastomycosis: Cladosporium carrionii
Fonsecaea
Phialophora verrucosa
Exophiala
Chromoblastomycosis is common in this general area of the world: tropics
Chromoblastomycosis treatment: Surgery
Cautery with topical antifungals
Phaeohyphomycosis lesion -initiated most commonly by __1__ -can infect these parts of the body:__2__: Nodule or cyst

1. wound
2. sinus, brain, bone
Diagnostic feature of Phaeohyphomycosis: Melanized cell walls
Phaeohyphomycosis commonly causing fungi: Exophiala jeanselmei Phialophora richardsiae
Bipolaris spicifera
Wangiella dermatitidis
Treatment of Phaeohyphomcosis: Surgical excision and chemotherapy
-Amphotericin B and 5-Fluorocytosine or Itraconazole
2/3's of Mycetoma lesions are on this part of the body: feet
Mycetomas are characterized by this lesion: Indolent, deforming swollen lesions that contain numerous draining sinus tracts

*may take years to develop
How are Mycetomas diagnosed?: observation of 'grains' of fungal tissue in specimen
Mycetomas are caused by these fungi: Pseudallescheria boydii
Madurella mycetomatis
Madurella grisea
Exophiala jeanselmei
Acremonium falciforme
Fusarium
Scedosporium

*Pseudo Madur Exo Acre Fus Sced
Organisms that cause Mycetomas are all common ______ fungi: soil
Treatment for Mycetomas: Surgical debridement
Long-term chemotherapy
AMPUTATION
3 most common fungi causing Onychomycosis: Trichophyton rubrum
Trichophyton Mentagrophytes
Epidermophyton Floccosum
Causative agent of Superficial White Onychomycosis: Trichophyton Mentagrophytes

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