SUPERFICIAL MYCOSES
Assoc.Prof.Dr.Yesim Gürol
Learning Objectives
• To list dermatophytes
• To list subcutaneous mycoses
infections caused by
• dermatophytic fungi (dermatophytosis)
• Nondermatophytic fungi (dermatomycosis)
DERMATOPHYTOSES
• Trichophyton
• Epidermophyton
• Microsporum
• cause disease in animals and/or humans.
• have the ability to invade the skin,hair or nails.
• keratinophylic and keratinolytic.
• invade upper outermost layer of epidermis
dermatophytosis
tineas
ringworm
Morphology and Identification
identified by
• colonial appearance
• microscopic morphology
• Growth at Sabouraud’s dextrose agar at 25oC for two weeks
Epidermophyton floccosum
Microsporum audouinii
Microsporum canis
Microsporum persicolor
Trichophyton spp.
Epidemiology and immunity
• Begins in the skin after trauma and contact
• Host susceptibility depends on
• Moisture
• Warmth
• Spesific skin chemistry
• Composition of sebum and perspiration
• Youth
• Heavy exposure
• Genetic predisposition
• Dermatophytes are classified as anthropophilic, zoophilic or geophilic according to their
normal habitat.
Anthropophilic
• human hosts
• mild, chronic inflammation.
Zoophilic
• primarily in animals
• inflammatory reactions in humans who have contact with infected cats, dogs, cattle,
horses, birds, or other animals.
• followed by a rapid termination of the infection
Geophilic
• from the soil
• occasionally infect humans and animals.
• They cause a marked inflammatory reaction, which limits the spread of the infection and
may lead to a spontaneous cure but may also leave scars.
•Contagious
• Frequently transmitted by exposure to shed skin
scales, nails or hair containinh hyphae or conidia
• Tinea capitis
• Tinea favosa
• Tinea corporis
• Tinea pedis
• Tinea manuum
• Tinea imbricata
• Tinea cruris
• Tinea barbae
• Tinea nigra
• Tinea ungium
Tinea capitis
•
infection of the scalp with a dermatophyte fungus.
•
Hair can be infected with Trichophyton (abbreviated as "T".) and Microsporum ("M".) fungi.
classified according to how the fungus invades the hair shaft:
Ectothrix infection
• The fungal branches (hyphae) and spores (arthroconidia) cover the outside of the hair.
• Ectothrix infections can be identified by Woods light (long wave ultraviolet light) examination of the affected
area the vet uses this to check your cats fur.
Endothrix infection
• The hair shaft is filled with fungal branches (hyphae) and spores (arthroconidia).
• Endothrix infections do not fluoresce with Woods light.
Favus
• caused by T. schoenleinii infection
• honeycomb destruction of the hair shaft
macroconidia
When the hair is infected,
• ectothrix
• endothrix
• favic
Tinea capitis may present in several ways.
• Dry scaling – like dandruff but usually with moth-eaten hair loss
• Black dots – the hairs are broken off at the scalp surface, which is
scaly
• Smooth areas of hair loss
• Kerion – very inflamed mass, like an abscess
• Favus – yellow crusts and matted hair
• Carrier state no symptoms and only mild scaling
Trichophytid reaction (id reaction)
• The patient may become hypersensitive to constituents or products
of the fungus and develop allergic manifestations
• Usually vesicles
• Mostly on the hands
• No fungi present in lesion
Tinea capitis
Tinea capitis caused by Trichophyton mentagrophytes
Tinea barbae
Tinea pedis (Athlete’s foot)
Tinea corporis
Tinea unguium (onychomycosis)
Tinea ingualis (cruris) (jock itch)
SUBCUTANEOUS MYCOSES
• Normally reside in soil or vegetation
• Enter the skin or subcutaneous tissue by traumatic inoculation with
contaminated material
Sporotrichosis
Chromoblastomycosis
Eumycotic mycetoma
Subcutaneous zygomycosis
Subcutaneous phaeohyphomycosis
SPOROTRICHOSIS
• Sporothrix schenkii
• Thermally dimorphic
• Usually sporadic
• Most common in warmer climates
• Outbreaks related to forest work, mining, gardening
• Classic infection traumatic inoculation of soil or vegetable or organic
matter contaminated with fungus
• Zoonotic transmission with armadillo hunters and infected cats
• Chronic infection
• Nodular and ulcerative lesions that develop along lymphatics
• grossly may resemble a malignant process ‘squamous cell carcinoma’
• Dissemination to other sites rare !(bones,eyes,lungs, central nervous
system)
Specimens:
• Biopsy
• Exudate from lesions
• Culture
S.schenckii
Chromoblastomycosis (chromomycosis)
• chronic fungal infection
• slow growing verrucous nodules or plaques
• mostly in tropics
• Pigmented fungi (dematiaceous fungi)
Fonsecaea
Cladosporium
Exophiala
Cladophialophora
Rhinocladiella
Phialophora
• into the skin by trauma
• Verrucous, wart like lesions
• Cauliflower like nodules
• Rarely elephanthiasis
Subcutaneous phaeohyphomycosis
• Darkly pigmented septate hyphae in tissue
• Cutaneous and systemic infections
• Solitary encapsulated cysts in the subcutaneous tissue
• Sinusitis
• Brain abscesses (usually fatal)
• All exogenous molds that normally exist in nature
phaeohyphomycosis
• Exophiala,
• Phialophora,
• Wangiella,
•
Bipolaris,
•
Exserohilum,
•
Cladophialophora ,
•
Phaeoannellomyces,
• Aureobasidium,
•
Cladosporium,
• Curvularia
•
Alternaria
MYCETOMA
• Local swelling of infected tissue and interconnecting
• Often draining
• Sinuses or fistulae that contain granules
• Actinomycetoma....mycetoma caused by an actinomycete
• Eumycetoma....(Madura foot, maduromycosis) mycetoma caused by a
fungus
• Clinical features similar
• Treatment different
• Actinomycetomas more invasive
MYCETOMA
• After traumatic inoculation with soil contaminated with one of these
agents
• Feet, lower extremities, hands and exposed areas
• Suppuration, abscesses, granules,
• Contagious muscle and bone
• Deformation, loss of function
• Very rarely foreign body (e.g.cardiac pacemaker) infection