Superficial, cutaneous, subcutaneous, fungal infections Flashcards
what layer of the skin does superficial fungi infect
stratum corneum
pityriasis versicolor (tinea versicolor)
caused by
what promotes its growth
- common superficial infection of the skin caused by malassezia furfur
- dimorphic
- malassezia is part of our normal flora- found in lipophilic places- head, neck etc
- disease shows when environment promotes hyphal phase- like increased lipid production and moist heat
symptoms of pityriasis versicolor
- failure to tan- hypopigmentation (I pity you for your lack of a tan)- what levi had
- irregular scaly patches and yellow brown to dark brown color
- hyper/hypopigmentation
- primarily cosmetic
pityriasis versicolor diagnosis
- direct observation of skin scrapings and prepare WITH KOH PREP TO REVEAL “SPAGHETTI AND MEATBALLS”- yeast and hyphae
- don’t need to culture- grows slow and requires olive oil
treatment of pityriasis versicolor
- topical-head to toe with KERATOLYTIC AGENTS LIKE SELENIUM SULFIDE AND SALICYLIC ACID) to remove organisms from the skin
- azoles
- relapse is common
- must change hygiene issues or physiology
Tinea nigra
- brown/black oval-shaped lesions of the skin
- caused by inoculation of superficial skin via contamination by soil, sewage wood or compost
- caused by EXOPHIALA WERNECKII
- most common in warm places- Texas, Carolinas, Alabama, Louisiana, FL
why does exophiala werneckii cause brown/black pigment
- produces melanin
diagnosis of tinia nigra
- skin scrapings (KOH) reveal TWO CELLED YEAST FORMS WITH DARK PIGMENT
Tinea nigra treatment
wash off with salicylic acid and selenium sulfide
azoles
black and white peidra
what are they
where can they be found?
what organisms cause black? white?
-hard gritty “stone” like granules on hair shaft
-can be found in soil or compost
- black = peidra hortae
white = trichosporon beigelii ( like white= beige)
from what can white piedra be contracted
contact with animals
how do you tell the difference between white and black peidra?
- white is fluffy collar around hair shaft, loosely adherent to pubic, axillary hair, beards and eyebrows
- black peidra- nodules that are hard- usually on scalp and firmly attached
diagnosis and treatment of black and white peidra
- microscopic examination of infected hairs
- treatment- shaving off the hair and practicing good hygiene
dermatophytes
- group of organisms causing infection so the skin, nails, and hair- generally limited to keratinized layers, epidermis and dermis
what are the three most common dermatophytes
-what are they capable of that helps them grow
- microsporum
- trichophyton
- epidermophyton
- > capable of degrading and using keratin as a nutrient source
what do dermatophytes typically induce?
infection symptoms
infections are referred to as….
- inflammatory reaction around the underlying tissue and can appear as circular (like ringworm)
- infections- itching, scaling of skin
- referred to as tinea and the anatomic position
tinea pedis
- chronic often
- look like dry skin and have pustules at the periphery of disease where active growth is occurring
- in toe webs and maybe heel and sides of foot/nails
tinia corporus
- dry lesions-red, round scaly with raised boarder
- inflamed periphery and pustules
- anywhere but typically on trunk
tinea captitis
- scalp infection
- distinct scaly lesion- patches of hair loss
- fungal elements can surround the hair or be present within the hair shaft
- FLAVUS- MASS OF HYPHAL ELEMENTS SURROUNDING THE BASE OF THE HAIR SHAFT
tinea cruris
- jock itch
- “crura”
- lesions present in the groin
- 90% in men
- rounded boarder with raised boarders
tinea unguium-onychomycosis
- infection of the nail plate and bed
- hyperkeratosis and discoloration- dry, cracked and brittle disfigured nail
- painful
- DM and AIDS pt
diagnosis of tinea unguium
- see fungal elements via hair and nail samples
- confirms fungal involvement but DOES NOT REVEAL IDENTITY- NEED MICRO/MACRO AND METABOLIC CHARACTERISTICS
- WOODS LAMPS- UV LAMP THAT FLUORESCE SOME BUT NOT ALL FUNGI BUT HELPS WITH CHOOSING WHAT HAIR TO PLUCK
why is it difficult to treat tinea unguium?
- because it’s hard for topical treatments to penetrate nail bed
- must take oral meds
treatment for dermatophyte infections
- treat with exfoliate agent and topical azoles
-GRISEOFULVIN (greasy like your head) frequently used to treat tinea capitus
-
candidiasis
- caused by many yeasts but most common is c. albicans
- causes diaper rash and dishawasher’s hands
- look like papulues or plaques-redness, tenderness and cracking
- usually between webbings
- flakey. scaly
forms of c. albicans
yeast- normal flora
hyphal forms- tissue
pseudohyphal
chronic mucocutaneous candidiasis
- superficial infections at several anatomical sites like the mouth, face and nails
- associated with t cell deficits and endocrine disorders
- granulomatous response to infection causes disfigurement and discomfort
- IMMUNOSUPPRESSED PEOPLE
Disseminated candidiasis
- increase colonization by disrupting normal flora
- breakdown of normal physical barriers
- immune suppression
- it is the hematogenous spread of organisms to the liver, spleen, lungs and eyes, bones and joints
treatment for candidiasis?
-IV amphotericin B with or without fluconazole
sporotrichosis
- infection of cutaneous and subcutaneous tissue with lymphatics
- caused by sporothrix schenckii - dimorphic fungus found in soil/nature
- traumatic inoculation- moss, rose spliters, wood splinter
presentation of sporotrichosis
- inflammation at site of inoculation followed by painless granuloma
- ulcerates and creates open sore- as this happens, organism is spreading along lymphatics
diagnosis ad treatmet of sporotrichosis
- not really observed in tissue
- must cultivate from pus or tissue
treat- oral potassium iodide, oral azoles
chromoblastomycosis
- seen in tropics
- traumatic inoculation of soil fungi
- presents as a wartlike lesion and then develops into red/gray (IE CHROMO) CAULIFLOWER like lesions THAT ARE
- painless
Diagnosis and treatment of chromoblastomycosis
- brown-pigmented hyphae in skin scrapings
- MEDLAR BODIES - COPPER COLORED SPHERICAL CELLS
treatment of chromomycosis
- surgical removal of lesions
- oral antifungals- 5fluorocytosine
mycetoma
- Madura foot
- chronic, subcutaneous infection usually of foot
- obtained thru traumatic inoculation of soil-inhabiting fungi
mycetoma progression of disease
- usually slow
- starts with papule at site of inoculation
- lesion ulcerates releasing pus and blood
- draining tracts or sinuses develop causing discharge
- underlying bone involved makin gpitting lesions
diagnosis of mycetoma
- observation of colored GRAINS IN PUS, TISSUE AND DISCHARGE- compacted hyphae
treatment of mycetoma
surgery and antifungal
