Mycosis Flashcards
Type of mycosis?
Superficial mycosis
Cutaneous
Subcutaneous
Dimorphic system
Opportunistic systemic
Superficial infected
Skin and hair shaft
1-Harmless,unware
2-no living tissue ear invaded.
3-no pathological change are elicated
Cutaneous infected!
No living tissue is invaded
Hair,skin nail
Opportunistic systemic
Occur in immunodeficient patient (normal defnce mechanism ars impaired)
Malassezia species
basidiomycetous yeasts and form part of the normal skin flora of humans and animals. The genus now includes 14 species of which 13 are lipid dependent
most frequently found species responsible for colonisation of humans
M. sympodialis, M. globosa, M. slooffice and M. restricta
Malassezia species may cause various skin manifestations including
1-versicolor,
2- seborrhoeic dermatitis,
3-dandruff, atopic eczema
4- folliculitis
Fungaemia due to
lipid-dependent Malassezia species
Fungaemia usually occurs
in patients with central line catheters receiving lipid replacement therapy, especially in infants
Pityriasis versicolor
1.chronic,
2. superficial fungal disease of the skin characterised by well-demarcated white, pink, fawn, or brownish lesions, often conjoining,
3.covered with thin scales.
colour varies according
1-normal pigmentation of the patient,
2-exposure of the area to sunlight,
3- the severity of the disease.
Lesions ocuur on
1-trunk,
2-shoulders
3-arms,
rarely on the neck and face
Seborrhoeic dermatitis is caused by
Malassezia
Clinical manifestations of seborrhoeic dermatitis
1-erythema (red patches) and Scaling in areas with a rich supply of sebaceous glands ie: the scalp, face, Eyebrows, ears and upper trunk
2-Lesions are red and covered with greasy scales and itching is common in the scalp.
skin scrapings for a lab diagnosis are unnecessary for?
Seborrheic dermatitis
Fungaemia
causing by catheter
acquired fungaemia in
neonate and adult patients undergoing lipid replacement therapy.
Diagnosis for fungaemia requires
special culture media and blood drawn back through the catheter is the prefer specimen
Smoe patient with fungaemia may be develope
Small embolic lesions in the lung and other organ
Clinical material:
Skin scrapings from patients with superficial lesions, blood and indwelling catheter tips from patients with suspected fungaemia.
Direct microscopy:
Skin scrapings taken from patients with Pityriasis versicolor rapidly identified when mounted in 10% KOH, unipolar, broad base budding yeast cells
M. furfur
is a lipophilic yeast,
M. furfur in vitro growth must be stimulated by
natural oils or other fatty substances
most common method used
Sabouraud’s dextrose agar containing cycloheximide (actidione) with olive oil
White piedra
-A superficial fungal infection of the hair shaft caused by
Trichosporon
Infected hair develop
soft greyish-white nodules along the shaft
Infections are usually localised
axilla or scalp but may also be seen on facial hairs and sometimes pubic hair.
characteristic of white piedra.
The presence of irregular, soft, white or light brown nodules, 1.0-1.5 mm in length, firmly adhering to the hairs
Colonies Trichosporon in cultura
white or yellowish to deep cream colored, smooth, wrinkled
Black piedra
superficial fungal infection of the hair shaft caused by Piedra hortae,
localised to the scalp but may also be seen on
hairs of
the beard, moustache and pubic hair.
Black piedra mostly affects young adults and epidemics in families have
been reported following the
sharing of combs and hairbrushes
Direct microscopy:
For both
Hairs should be examined using 10% KOH or calcofluor white.
Culture
Hair fragments should be implanted onto primary isolation media, like Sabouraud’s dextrose agar
Colonies of piedra hortae
Dark ,brown to black need 2-3 week to appear
Management
1-Shaving the hairs is the simplest method of treatment.
2-Topical application of an imidazole agent may be used to prevent reinfection.
Species for Trichosporon most common clinical isolates
1- T.asahl,
2-T. asteroides,
3-T inkin,
4-ovoides
Causative agent of black piedra
Piedra hortae
Cutaneous Mycoses
• These are superficial fungal infections of the skin, hair or nails. •No living tissue is invaded,
skin, hair or nails. •No living tissue is invaded,
Dermatophytosis (tinea or ringworm) of the
scalp, glabrous skin, and nails
Dermatophytosis cause by
group of fungi known as dermatophytes
nutrient source of dermatophytes
utilize keratin
ability to utilize keratin as a nutrient source by
enzyme [keratinase
disease process in dermatophytosis is unique for two reasons
1-human or animal infection for the survival and dissemination of their species.
2-No living tissue is invaded
Tinea cruris (spread the fungus from foot)
Most common in male
Tinea cruris refers to dermatophytosis of the proximal medial thighs Thus the usual causative agents are
1-T. rubrum
,2- T. interdigitale
3-E. floccosum.
Tinea unguium (dermatophyte onychomycosis) classifieds as
1-Superficial white onychomycosis,surface of nail
2-invasive,subungual (beneath the nail) most common form of dermatophyte onychomycosis
The fungus invades:
a) Distal nail bed causing hyperkeratosis of the nail bed and thickening of the nail plate.
b) Lateral Subungual onychomycosis begins at the lateral edge of the nail and
often spreads to=> entire nail => nail plate.
c) Proximal subungual onychomycosis, the fungus invades under the cuticle and
infects the proximal causing yellowish-white
spots which slowly invade the lunula and then the nail plate.
Tinea corporis refer to dermatophytosis glabrous skin caused by
Anthrophophilic such as T.rubrum
Tinea corporis spread to other sites by
Geophilic
Zoophilic
Such as 1-M.gypseum 2-M.canis
By contant with contaminated soil ,animal
Tinea capitis:refers to dermatophytosis of the scalp. • Three types of in vivo hair invasion are recognised:
- Ectothrix
2 . Endothrix
3 . Favus
Endothrix hair invasion is characterised by hair invasion is characterised by the
,Agent?
1 . development of
arthroconidia within the hair shaft only. The cuticle of the hair remains
intact
2 . Trichophyton tonsurans and T. violaceum
Exothrix hair invasion is characterised by. ,agent?
development of arthroconidia on the outside of the hair shaft. The cuticle of the hair is destroyed
Common agents include Microsporum canis, Nannizzia.gypsea, Trichophyton equinum and T. verrucosum.
Favus caused by
Trichophyton schoenleinii, produces favus-like-
crusts or scutula and corresponding hair loss:b
Exothrix
Grey patch ringworm
Endothrix
Black dot ringworm
Clinical material for dermatophyte
Skin scraping
Nail scraping
Epilated hair
بس نشوف( arthoconidia, hyphae)
لنعرف أنها => dermatophyte
Direct microscopy for dermatophytosis
: Skin Scrapings, nail scrapings and epilated hairs should be examined using 10% KOH or calcofluor white mounts
Culture
Sabouraud dextrose agar containing cycloheximide
Treatment of dermatophytosis
Topical antifungal agents if you ineffected ,use systemic therapy
Systemic candidiasis is usually seen in
Cell mediated immune deficiency
Aggressive cancer treatment
Immunosuppression
Transplantation Therapy
Oropharyngeal candidiasis: including
thrush, glossitis(inflammation of the tongue), stomatitis and angular cheilitis.
predisposing factors
The use of broad-spectrum antibiotics,
corticosteroids,
cytotoxic drugs, and
radiation therapy
Symptoms of oropharyngeal candidiasis
burning or dryness of the mouth, loss of taste, and pain on swallowing
Cutaneous candidiasis: including
intertrigo (by friction, moisture), diaper candidiasis, paronychia and onychomycosis
Clinical material for candidiasis
Skin and nail scrapings, arine, sputum and bronchial washings, cerebrospinal fluid pleural fluid and blood; tissue biopsies from various visceral organs and indwelling catheter tips
Direct microscopy: candidiasis
1 Skin and nails should be examined using 10% KOH or calcofluor white mounts
2 Exudates and body fluids should be centrifuged and the sediment examined using either 10% KOH or calcofluor white mounts and/or gram stained smears
3 Tissue sections should be stained using PAS digest, Grocott’s methenamine silver (GMS) or Gram stain
Culture candidiasis
Colones are typically white to cream colored with a glabrous to waxy surface (Different colors in Chromogenic media)
Serology for candidiasis
Detect for candidiasis antibody by
ELISA ,RIA
Often neg in immunocompromised patients in beginning infected
