Superficial, cutaneous, subcutaneous, fungal infections

Question 1

what layer of the skin does superficial fungi infect

Answer 1

stratum corneum

Question 2

pityriasis versicolor (tinea versicolor)
caused by
what promotes its growth

Answer 2

• 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

Question 3

symptoms of pityriasis versicolor

Answer 3

• 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

Question 4

pityriasis versicolor diagnosis

Answer 4

• 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

Question 5

treatment of pityriasis versicolor

Answer 5

• 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

Question 6

Tinea nigra

Answer 6

• 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

Question 7

why does exophiala werneckii cause brown/black pigment

Answer 7

• produces melanin

Question 8

diagnosis of tinia nigra

Answer 8

• skin scrapings (KOH) reveal TWO CELLED YEAST FORMS WITH DARK PIGMENT

Question 9

Tinea nigra treatment

Answer 9

wash off with salicylic acid and selenium sulfide

azoles

Question 10

black and white peidra
what are they
where can they be found?
what organisms cause black? white?

Answer 10

-hard gritty “stone” like granules on hair shaft
-can be found in soil or compost
- black = peidra hortae
white = trichosporon beigelii ( like white= beige)

Question 11

from what can white piedra be contracted

Answer 11

contact with animals

Question 12

how do you tell the difference between white and black peidra?

Answer 12

• 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

Question 13

diagnosis and treatment of black and white peidra

Answer 13

• microscopic examination of infected hairs

- treatment- shaving off the hair and practicing good hygiene

Question 14

dermatophytes

Answer 14

• group of organisms causing infection so the skin, nails, and hair- generally limited to keratinized layers, epidermis and dermis

Question 15

what are the three most common dermatophytes

-what are they capable of that helps them grow

Answer 15

• microsporum
• trichophyton
• epidermophyton
• > capable of degrading and using keratin as a nutrient source

Question 16

what do dermatophytes typically induce?
infection symptoms
infections are referred to as….

Answer 16

• 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

Question 17

tinea pedis

Answer 17

• 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

Question 18

tinia corporus

Answer 18

• dry lesions-red, round scaly with raised boarder
• inflamed periphery and pustules
• anywhere but typically on trunk

Question 19

tinea captitis

Answer 19

• 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

Question 20

tinea cruris

Answer 20

• jock itch
• “crura”
• lesions present in the groin
• 90% in men
• rounded boarder with raised boarders

Question 21

tinea unguium-onychomycosis

Answer 21

• infection of the nail plate and bed
• hyperkeratosis and discoloration- dry, cracked and brittle disfigured nail
• painful
• DM and AIDS pt

Question 22

diagnosis of tinea unguium

Answer 22

• 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

Question 23

why is it difficult to treat tinea unguium?

Answer 23

• because it’s hard for topical treatments to penetrate nail bed
• must take oral meds

Question 24

treatment for dermatophyte infections

Answer 24

• treat with exfoliate agent and topical azoles
  -GRISEOFULVIN (greasy like your head) frequently used to treat tinea capitus
  -

Question 25

candidiasis

Answer 25

• 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

Question 26

forms of c. albicans

Answer 26

yeast- normal flora
hyphal forms- tissue
pseudohyphal

Question 27

chronic mucocutaneous candidiasis

Answer 27

• 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

Question 28

Disseminated candidiasis

Answer 28

• 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

Question 29

treatment for candidiasis?

Answer 29

-IV amphotericin B with or without fluconazole

Question 30

sporotrichosis

Answer 30

• 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

Question 31

presentation of sporotrichosis

Answer 31

• inflammation at site of inoculation followed by painless granuloma
• ulcerates and creates open sore- as this happens, organism is spreading along lymphatics

Question 32

diagnosis ad treatmet of sporotrichosis

Answer 32

• not really observed in tissue
• must cultivate from pus or tissue

treat- oral potassium iodide, oral azoles

Question 33

chromoblastomycosis

Answer 33

• 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

Question 34

Diagnosis and treatment of chromoblastomycosis

Answer 34

• brown-pigmented hyphae in skin scrapings

- MEDLAR BODIES - COPPER COLORED SPHERICAL CELLS

Question 35

treatment of chromomycosis

Answer 35

• surgical removal of lesions

- oral antifungals- 5fluorocytosine

Question 36

mycetoma

Answer 36

• Madura foot
• chronic, subcutaneous infection usually of foot
• obtained thru traumatic inoculation of soil-inhabiting fungi

Question 37

mycetoma progression of disease

Answer 37

• 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

Question 38

diagnosis of mycetoma

Answer 38

• observation of colored GRAINS IN PUS, TISSUE AND DISCHARGE- compacted hyphae

Question 39

treatment of mycetoma

Answer 39

surgery and antifungal