SUPERFICIAL MYCOSES Flashcards
What are the predisposing factors of SUPERFICIAL MYCOSES AND DERMATOPHYTOSIS?
o Humidity
o Immunosuppression
o Poor hygiene
fungi that require keratin for growth
Dermatophytes
Hair infection with nodular masses of fungal
elements surrounding the shaft
Piedra
• Infections of the skin
• Macular patches that are non-scaly
Tinea
What are the causative agents of superficial mycoses?
• Malassezia furfur
• Exophiala werneckii
• Trichosporon beigelli
• Piedraia hortae
These are the causative agents in the skin.n
Malassezia furfur and Exophiala werneckii
These are the causative agents in the hair,
Trichosporon beigelii and Piedraia hortae
What is the appearance of Malassezia furfur microscopically?
Thick, round oval in clusters
Lipophilic yeast
Found as normal flora on the skin
Malassezia furfur
(char. By
superficial, brownish, scaly areas in light-
skinned ind. and lighter areas in dark-skinned
Pityriasis versicolor/tinea
Give 2 diseases caused by Malassezia furfur
Pityriasis versicolor/ Tinea versicolor
Pityriasis folliculitis
• Seborrheic dermatitis; Dandruff
• Systemic infection
What is the most common presentation of the major clinical manifestation of Malassezia furfur?
Fawn-colored macules
What are the clinical manifestations of Malassezia furfur?
Hyper/hypopigmented
Lesions are well demarcated
Fawn-colored macules
Malassezia furfur is positive to this light green fluorescence.
Wood’s lamp
Follicular papules and pustules
Itchy and often appear after sun exposure
Pityriasis folliculitis
small circumscribed elevation
Papule
small inflammatory swelling containing
pus
Pustule
Changes in quantity and composition of sebum
Increase in alkalinity of skin
• External local factors such as occlusion
Seborrheic dermatitis
greasy condition of the scalp, face, sternal region
and elsewhere due to overactivity of sebaceous glands (may
result to alopecia, acne
Seborrhoea
What are the clinical manifestations of seborrheic dermatitis?
•Erythema and scaling in areas with a rich supply of
sebaceous glands
• Lesions are covered with greasy scales
• Itching is common in the scalp
Common among infants as catheter acquired
Systemic Infection
What is the laboratory diagnosis of systemic infection of malassezzia furfur?
Skin scrapings
Blood
Indwelling catheter tips
What is used for the direct microscopy of systemic infection of M. furfur?
10% KOH ((glycerol with Parker ink or Calcofluor white)
What are the characteristics of the systemic infection of the M. Furfur?
o Clusters of thick-walled round budding
yeast-like cells
o Short angular hyphal forms
o Yeast cells (3-7um)
“Spaghetti and Meatballs”
What is the measurement of yeast cells under the systemic infection of M.furfur?
3-7um
What is the initial clue of systemic infection of M.furfur?
lack of growth in the
absence of oil
A specialized isolation
medium containing glycerol-mono-
oleate. It is a resembling bacteria-like
colonies
Dixon’s agar
This is a culture medium used for the systemic infection of malessezia furfur.
Sabouraud’s dextrose agar or Sheep blood agar
containing Acti-Dione with olive oil
What is the microscopic appearance of malassezia furfur?
Broad-based buds
The collarettes of the phialides
appear as distinct dark rings
separation the mother &
daughter cells
What is the other helpful features in detecting the systemic infection of M.furfur?
• White discoloration of skin or light brown discoloration
• Spaghetti and meatballs
• Oil and FA requirement
Mould
Exophiala werneckii
What is the disease associated with Exophiala werneckii?
Tinea nigra
• Chronic superficial fungal infection of the palms
• Brown to black macules (palmar, plantar, and other
surfaces of the skin)
• Well-defined dark patch with irregular margin, 1-5 cm
in diameter on palm; “stained appearance”
• Lesions: non-inflammatory and non-scaling
• Both tropics and temperature zones
• Usually less than 20 years old female (3:1)
• Predisposing factor: excessive sweating
Tinea nigra
Under Tinea Nigra, what is the measurement of the dark path with irregular margin on the palm?
1 - 5cm
What is the predisposing factor of Tinea nigra?
Excessive sweating
What is the laboratory diagnosis of exophiala werneckii?
Skin scrapings
What is the primary isolation media of exophiala werneckii?
Sabouraud’s dextrose agar
Pigmented brown to black (dematiaceous)
septate hyphal elements
Sabouraud’s dextrose agar
• Initially colonies are mucoid, yeast-like and shiny black
(young yeast)
• Abundant aerial mycelia and become velvety, dark
olivaceous in color (mature mold)
• Serology not required for diagnosis
Exophiala werneckii
