L3 Tinea Scabies Flashcards
Dermatophyte infections
Tinea Capitis
Tinea Corporis
Tinea Cruris
Tinea Pedis
Tinea capitis
fungal infection
common in children, african-americans, decreased hygiene, etc
acquired via direct contact with individual or object
scaly patches w/ alopecia
black dots, widespread, kerion, favus
Kerion
boggy edematous painful plaque
favus
multiple cup-shaped yellow crusts (scutula) “honeycomb”
assoc signs of tinea capitis
cervical adenopatchy
erthema nodosum
dermatophytid rxn: eczema like often after anti fungal therapy
Dx of tinea capitis
physical exam KOH prep Dermoscope (see cork-screw hairs) culture: slow wood's lamp: meh
tx of tinea capitis
Griseofulvin, systemic anti fungal for 6-12 weeks
topicals do not penetrate the hair follicle enough
Tinea corporis
common in caregivers of children with t. capitis
athletes with skin to skin contact, t. corporis gladiatorum
immunocompromised
pruritic annular erythematous plaque
central clearing, raised border
Dx of t. corporis
H&P
KOH prep
culture
tx of t. corporis
topical antifungal
Clotrimazole at least 2 weeks
in special circumstances could use systemic anti fungal
itraconazole
clomitrazole
topical antifungal
itraconazole
systemic antifungal
tinea incognito
tinea infection that is made worse b/c of topical steroid use. can cause local immune suppression allowing the fungus to proliferate
majocchi’s granuloma
follicular and perifollicular dermatophyte infection of the deep dermis, and may be found in immunocompetent and immunocompromised people
aka using steroid cream
tinea cruris
"jock itch" begins in inguinal fold contributing factors: sweat/humidity males obesity athlete's foot occlusive clothes well-marginated, scaly, annular plaque with raised border scrotum is spared usually pruritic and painful
Dx of t. cruris
H&P
KOH prep
Culture
tx of t. cruris
topical anti fungal
clotrimazole
resistant cases:
oral itraconazole
drying talcum powder
avoid tight clothes
tinea pedis
most common dermatophytosis in the world
caused by occlusive footwear and communal showers
Acute and chronic forms
acute t. pedis
itchy/painful vesicles/bulla following sweating
secondary staph infections can occur
usually self-limited, intermittent, and recurrent
chronic t. pedis
slowly progressive infection that persists indefinitely
erosion/scales and fissures b/w toes
“moccasin ringworm”
tinea manuum
moccasin ringworm
sharp demarcation with accumulated scale in skin creases
tinea manuum
“vacuum for man”
jkjkjk
two feet & 1 hand infected
dx of tinea pedis
H&P
KOH prep
Cuture
Gram stain if suspected bacterial infection
tx of t. pedis
topical antifungal clotrimazole x 4 weeks oral anti fungal for chronic/extensive disease itraconazole burrow's wet dressings treat secondary infections
onychomycosis
infection of nail by fungus, yeast, or non-dermatophyte molds
primarily cosmetic
can be painful
increases risk of concurrent infection
distal, proximal, & white superficial subtypes,
distal subungal onychomycosis
most common subtype usually toenails starts with big toe white/brown/yellow starting at distal corner and spreads toward cuticle nail breaks, exposing nail bed
proximal subungual onychomycosis
starts near cuticle and progresses distally
usually toenails
uncommon
immunocompromised (AIDS)
white superficial onychomycosis
starts with dull white spots on nail plate
usually toenails
spreads centrifugally
can be scraped for lab sample
yeast onychomycosis
thickening of nail with yellow/brown discoloration
usually fingernails
may cause paronychia
dx of onychomycosis
difficult to distinguish clinically KOH prep of nail scrapings culture histopathology (bx) most of the time fingernails carry yeast toenails carry dermatophytes
tx of oncyhomycosis
not obligatory
topical medications are usually ineffective
oral terbinafine if dermophyte infection 6 weeks on fingernails
12 weeks on toenails
oral itraconazole if non-dermatophyte infection 6 weeks for fingernails
12 weeks for toenails
intertrigo
any infectious or non-infectious inflammatory condition of two closely opposed skin surfaces
candidal intertrigo
risk factors: moisture, skin friction, immunocomp
typically involves areas of the groin, mammary/abd folds, web spaces, and axilla
erythematous, macerated (soggy) plaques and erosions
satellite papules/putules
fine peripheral scaling
dx of c. intertrigo
H&P
KOH prep
Culture
tx of c. intertrigo
topical medication
nystatin cream
systemic medication in severe cases
itraconazole
tinea versicolor
fungal infection of the normal skin flora that converts into mycelia form common in humid climates hyperhidrosis immunosuppressed NOT CONTAGIOUS macules, patches, plaques on trunk and upper extremity typically asymptomatic mildly pruritic variety of colors hypo/hyper/erythematous
dx of t. versicolor
H&P
KOH
Wood’s lamp
tx of t. versicolor
topical anti fungal medications clotrimazole selenium sulfide (lotion/shampoo/foam) Zinc pyrithione (shampoo) systemic medications for extensive disease or failed topical treatment itraconazole pigment changes can last months after tx
scabies
parasitic infection mite buries herself in the stratum corneum and lays 2-3 eggs/day x ~30days eggs hatch in 10 days can live without host for 3 days transmission through direct contact initial erythematous macule/papule burrow line is pathognomonic back and head are often spared of infestation severe pruritus, worse at night
crusted scabies
norwegian scabies
presentation in immunocompromised pts
fissures=avenue for bacteria, can lead to sepsis
requires oral medications
dx scabies
visualization of burrow
microscopic identification of mites/eggs/feces
dermatoscopy
scabies tx
permethrin 5% cream initial dose followed by 2nd dose 10-14 days later
oral ivermectin initial dose followed by 2nd dose 14 days later
2nd dose is necessary to kill any eggs that have hatched
tx of pruritus with antihistamines and emoillants
pubic lice
cause by crab louse
can be seen with the naked eye
most commonly affect teens and young adults via sexual contact
pt presents with itching in the groin/axilla
dx and tx of pubic lice
microscopy
permethrin 1% cream, recheck/repeat in 10 days
treat sexual partners
30% of pts will have a concurrent STI
