Cutaneous Fungal Infections Flashcards
Tinea Versicolor aka what is it? What is it caused by? So what happens to the skin and cells? Who is this most common in? Risk factors
- aka Pityriasis versicolor
- a superficial yeast infection caused by Pityrosporum ovale (aka Malassezia furur which is normally found on human skin)
- Organism oxidizes fatty acids in the skin and inhibits tyrosinase in the melanocytes leading to the loss of pigmentation
- most common in teens and young adults
- Risk factors: heat, humidity, excessive sweating, use of topical skin oils, HIV infection
Tinea versicolor
characterized by what?
sx
-characterized by hypopigmented lesions on the TRUNK that are asymptomatic
sx:
- asymptomatic (sometimes puritic)
- velvety tan, pink, or white macules
- hypopigmented areas that do not tan with the rest of the skin
- 4-5 mm or confluent
- trunk, upper arms, neck, and groin
- lesions may scale if scraped
Tinea versicolor
Lab findings
Treatment
Lab
- skin scrapings seen on KOH (which clears the slide of epithelial cells) prep show budding spores and large hyphae “spaghetti and meatballs”
- fungal culture is NOT helpful
- “its really a clinical dx”
Tx
-DOC: selenium sulfide lotion or shampoo 2.5% once daily for seven days. To prevent recurrence, maintenance therapy twice a month (sometimes it come comes back, sometimes it doesnt)
- other options: ketoconazole (shampoo), itraconazole (tablet), diflucan (tablet)
What are the 3 species of fungi that cause human tinea infections? (dermatophytes)
- trichophyton
- microsporum
- epidermophyton
Dermatophytes where do they grow what do they do risk factors transmission
-skin, hair, and nails leading to localized symptoms
- dermatophytes digest keratin
- -scaling
- -nails thicken and crumble
- -hair loss
-risk factors:warm, moist, occluded environments, family history, compromised immune system, alteration in normal flora
- spread by human contact
- -humans, animals, inanimate objects
What layer of the skin are the tinea infections located?
located in the stratum corneum and caused by a variety of fungal species
such as-
- trichophyton rubrum
- trichophyton tonsurans
- trichophyton mentagrophytes
- microsporum canis
- epidermophyton floccosum
Where is: Tinea corporis tinea cruris tinea pedis tinea capitis tinea unguium
Tinea corporis- body "ring worm" tinea cruris- groin "jock itch" tinea pedis-feet "athletes foot" tinea capitis-scalp tinea unguium-nails
Tinea
sx
dx
sx
- localized puritis, burning, and stinging
- if inflammatory rxn, may have erythema and vesicles in addition to the sx above
dx
- microscopic eval: skin margin scraping and KOH prep
- fungal culture: takes 2 weeks (do this when it is recurrent/resistant)
- woods lamp: will only ID microsporum species
Tinea corporis
- where
- what does it look like
- transmission
- tx
- where: face, limbs, trunk
- what does it look like: ring shaped lesions with well demarcated margins, central clearing, scaly erythematous border
- transmission: contact (humans, animals, sports equipment)
- tx: topical azole (nystatin, ketoconazole, clotrimazole, monistat/miconazole)
Tinea Cruris
- where
- what does it look like
- hallmark sx
- tx
- where: groin, inguinal folds, spares the scrotum
- what does it look like: *borders are distinct, lesions large, erythematous, macular with central clearing
- hallmark sx: pruritus with burning
- tx: topical azole antifungal (nystatin, ketoconazole, clotrimazole, miconazole)
Tinea pedis
- where
- sx
- tx
Interdigital: scaling, maceration (breaking down from being consistently wet), fissures b/w toes
Plantar: diffuse scaling of the soles
acute vesicular: vesicles and bullae on the sile of the foot, great toe, and instep
tx: topical azole antifungal (nystatin, ketoconazole, clotrimazole, miconazole
Tinea capitis
- where
- sx
- tx
- most common in children
- where: scalp
- sx: inflamed scaly, alopecic patches
- diffuse scaling with round alopecic patches due to broken hair shafts
- -tender, pustular nodules
-tx: griseofulvin for 8 weeks OR terbinafine for up to 4 weeks (cannot use topical therapy for this)
Tinea unguium aka where sx tx
aka: onychomycosis
where: typicall toenails but can affect fingernails, usually moves distal to proximal
sx: asymptomatic! (sometimes discomfort)
tx: oral terbinafine (lamisal) 250 mg po qday x 6 weeks for fingernails and 12 weeks for toenails (monitor LTFs and CBC)
- -alternative: itraconazole
- -a variety of topical rxs are available but have limited efficacy
Cutaneous candidiasis where are the following? intertrigo balantitis candidal folliculitis candidal paronychia thrush diaper dermatitis
intertrigo: axillae, under breasts, groin, intergluteal folds
balantitis: glans penis
candidal folliculitis: follicular pustules
candidal paronychia:nail folds
thrush: mouth and tongue
diaper dermatitis
Candidiasis
risk factors
- infection
- recent abx use
- diabetes
- systemic and topical steroids
- immunosuppression
- warm, moist conditions
- break in the skin
