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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 immunity against Fungi:
-PRR domain proteins like __1__
1. Card9

2. Toll-like receptors
How are Superficial mycoses diagnosed?
Direct Observation and culture
Do superficial mycoses elicit an immune response?
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 _________
-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

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

Benign pigmentation
Places where Tinea Nigra are usually seen
South or Latin America
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

Black Piedra treatment
shaving or clipping hair

Topical or Oral Azoles
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
A ______ bacterial infection can be present along with Trichosporon (White Piedra)
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
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 _________
Cutaneous Mycoses infect ______ tissue and elicit ______
Living tissue

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


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
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
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
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
Tinea Capitis involves these parts of the body

Tinea capitis is most common in these people
pre-pubescent blacks
Tinea capitis DOC's

*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 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

*seen in 2-3% of the pop.
Most common form of Onychomycosis and its agent

Distal and Lateral Subungual Onychomycosis (DLSO)

Dermatophyte fungi
DOC's for Onychomycosis
Lamisil - oral 6-12 wks
Sporanox - oral, pulse dosing
-1 week on, 3 off for 5 months
Loprox (tea tree oil)
Downfall of Lamisil (Terbinifine)
some Hepatocytoxicity
Downfall of Sporanox (Itraconazole)
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

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

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
-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)
-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?

~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
Phialophora verrucosa
Chromoblastomycosis is common in this general area of the world
Chromoblastomycosis treatment
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
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

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

Trichophyton Mentagrophytes

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