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Micro Exam 2 superfiscial, cutaneous, etc fungals

Terms in this set (50)

Pityriasis (tinea) versicolor
a fungal overgrowth in the stratum corneum epidermidis, which disrupts melanin synthesis and manifests as hypo-pigmented or hyperpigmented skin patches, usually on the trunk of the body. There is usually little tissue response.
Pityriasis (tinea) versicolor epidemiology
overgrowth of the lipophilic fungus, Malassezia furfur, part of the normal flora. M. furfur also causes fungemia in premature infants on intravenous (IV) lipid supplements.
Pityriasis (tinea) versicolor dx
potassium hydroxide (KOH) mount of skin scales showing short, curved, septate hyphae and yeastlike cells (spaghetti and meatballs appearance).
Tinea nigra
superficial infection of the stratum corneum epidermidis on the palmar or plantar surfaces causing benign, flat, dark, melanoma-like lesions
Tinea nigra cause
caused by a dematiaceous (darkly pigmented) fungus that produces melanin, which colors the skin
General aspects of cutaneous mycoses
caused by any of the dermatophytes or Candida spp
--dermatophytes,homogeneous group of filamentous fungi,
-- three genera, Epidermophyton, Microsporum, and Trichophyton.
- Most cutaneous infections are dermatophytic.

- Candida infections are more frequently mucocutaneous or in skin folds and sometimes disseminate.
- Dermatophytes do not disseminate.
how are cutaneous mycoses classified?
classified by the area of body involved
Cutaneous mycoses: epidemiology from animal
cause lesions that are significantly inflammatory. Two common zoophilic species are Microsporum canis and Trichophyton rubrum.
Cutaneous mycoses: epidemiology from humans
lesions that are less inflammatory. Two common anthropophilic species are Epidermophyton floccosum and Microsporum audouinii.
Cutaneous mycoses Dx
often treated empirically or diagnosed by microscopic examination of skin, hair, or nail material mounted in 10% KOH. Dermatophytes will show up as relatively unbranched hyphae sometimes with arthroconidia. Selection of areas to sample in Microsporum infections may be aided by the use of a Wood's (ultraviolet [UV]) lamp
Cutaneous mycoses complications
Lesions may become superinfected with bacteria that also must be treated. Pus, when present, is a solid indication of super-infection
Cutaneous mycoses Tx
usu. just topical antifungals
--require treatment with oral drugs if hair (and hair follicles) are involved.
Cutaneous mycoses ID reaction:
New sterile lesions may arise during treatment. This hypersensitive state is known as the dermatophytid (or "id") reaction, a reaction to circulating fungal antigens that indicates treatment response
Tinea capitis
ringworm of the scalp skin and hair
Anthropophilic tinea capitis
gray patch
Occurs in prepubescent children and is epidemic, spread by head gear, combs, and so forth.
It is caused by Microsporum audouinii.
It is usually noninflammatory and produces gray patches of hair
Microsporum audouinii.
causes Anthropophilic tinea capitis
Zoophilic tinea capitis
transmitted by pets or farm animals.
--most commonly caused by Microsporum canis or by Trichophyton mentagrophytes.
--inflammatory, often with boggy tender areas called kerion.
--Temporary alopecia, kerion, keloid, and inflammation may result.
Black-dot tinea capitis
chronic infection occurs in adults and is characterized by
hair breakage, followed by filling of follicles with dark conidia.
It is caused by Trichophyton tonsurans.
Trichophyton tonsurans.
causes Black-dot tinea capitis
Microsporum canis or by Trichophyton mentagrophytes
causes Zoophilic tinea capitis
kerion
can be caused by Zoophilic tinea capitis
Tinea barbae
infection is an acute or chronic folliculitis of the beard, neck, or face most commonly caused by Trichophyton verrucosum and it may produce pustular or dry, scaly lesions.
Trichophyton verrucosum
causes Tinea barbae
Tinea corporis
dermatophytic infection affects glabrous skin and is commonly caused by T. rubrum, T. mentagrophytes, or M. canis.
It is characterized by annular lesions with an active border that may be pustular or vesicular
T. rubrum, T. mentagrophytes, or M. canis
causes Tinea corporis
Tinea cruris
jock itch--fungal infection of the groin
--often accompanied by athlete's foot or nail infections
--caused by E. floccosum, T. rubrum, T. mentagrophytes, or yeasts like Candida.
E. floccosum, T. rubrum, T. mentagrophytes
causes (along with candida) Tinea cruris
Tinea pedis
athlete's foot
--commonly caused by T. rubrum, T. mentagrophytes, or E. floccosum
Tinea pedis--3 clinical presentations
Chronic intertriginous tinea pedis (usually white macerated tissue between the toes)
Chronic dry, scaly tinea pedis (hyperkeratotic scales on the heels, soles, or sides of the feet)
Vesicular tinea pedis (vesicles and vesiculopustules)
Chronic intertriginous tinea pedis
white macerated tissue between the toes
Chronic dry, scaly tinea pedis
hyperkeratotic scales on the heels, soles, or sides of the feet
Vesicular tinea pedis
vesicles and vesiculopustules
Favus (tinea favosa)
highly contagious and severe form of tinea capitis with scutula (crust) formation and permanent hair loss caused by scarring
caused by Trichophyton schoenleinii
Trichophyton schoenleinii
causes Favus (tinea favosa) and Permanent hair loss
Candida albicans
seen in infected tissues as pseudohyphae, true hyphae, blastoconidia, and yeast cells but is still referred to as a yeast
Oral thrush
candida spp. a yeast infection of the oral mucocutaneous membranes and manifests as white curd-like patches in the oral cavity
Oral thrush in immunocomromised
may extend through gastrointestinal (GI) tract, causing a painful gastritis.
Vulvovaginitis or vaginal thrush
a yeast (Candida spp.) infection of the vagina that tends to recur
--thick yellow-white discharge, a burning sensation, curd-like patches on the vaginal mucosa, and inflammation of the peritoneum
Predisposition to Vulvovaginitis or vaginal thrush
diabetes, antibiotic therapy, oral contraceptive use, and pregnancy.
Vulvovaginitis or vaginal thrush Dx
KOH mount of "curd"
Cutaneous candidiasis
involves the nails (increases with prolonged use of false nails), skin folds of babies, obese individuals (visible as creamy growth), or groin (but generally also the penis).
--Lesions may be eczematoid or vesicular and pustular
--predisposed by moist conditions
Sporotrichosis
Rose Gardener's Disease
Sporothrix schenckii.
thermally dimorphic fungus taht causes Sporotrichosis/Rose Gardener's Disease
Sporotrichosis clinical presentation
generally not painful
--This subcutaneous, nodular, fungal disease
lymphocutaneous sporotrichosis
produces a chain of lesions on the extremities; with the older (lower) lesions ulcerating and the newer (upper) ones starting nodular
Sporotrichosis Diagnosis
clinical diagnosis is confirmed by culture;
histology is generally negative
Sporotrichosis Tx
itraconazole
Eumycotic mycetoma
subcutaneous
characterized by
(1) swelling (tumefaction),
(2) sinus tracts erupting through the skin (if not treated), and
(3) presence of "sulfur" granules microcolonies in the exudate
Eumycotic mycetoma causitive organisms
Pseudoallescheria boydii and Madurella sp., which are filamentous true fungi found in soil or on vegetation; entry is by traumatic implantation
Chromoblastomycosis
one of a group of infections caused by dematiaceous (dark) fungi and seen in tissues as pigmented, yeast-like bodies
colored lesions start out scaly and become raised, cauliflower-like lesions
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