Derm: lect 3 Flashcards
1
Q
list the dermatophyte infections
A
dermatophyte: fungi that require keratin for growth
- tinea capitis
- tinea corporis
- tinea cruris
- tinea pedis
2
Q
etiology of tinea capitis
A
- Trichophytan species
- Microsporum species
3
Q
pathogenesis of tinea capitis
A
- direct contact with infected individual or animal
- contact with contaminated object
4
Q
clinical presentation:
- scaly patches with alopecia
- patches of alopecia with black dots
- widespread scaling with subtle hair loss
- kerion
- flavus
- associated findings: cervical adenopathy; dermatophytid reaction
A
tinea capitis
5
Q
identify the multiple cup-shaped yellow crusts
A
favus (scutula)
6
Q
diagnostic evaulation for tinea infections
A
KOH prep
7
Q
treatment of tinea capitis
A
- if you suspect microsporum: Griseofulvin x 6-12 weeks
- if you suspect tichophyton: Terbinafine x 2-4 weeks
8
Q
Etiology of Tinea Corporis
A
- Trichophyton rubrum
9
Q
epidemiology of tinea corporis
A
- caregivers for children with tinea capitis
- athletes with skin to skin contact
- immunocompromised
- pets
10
Q
clinical presentation:
- pruritic, annular, erythematous plaque with central clearing and and advancing border
A
tinea corporis (ringworm)
11
Q
treamtent of tinea corporis
A
topical antifungals (“azole”)
- at least 2 weeks duration
- avoid nystatin
12
Q
etiology of tinea cruris
A
trichophyton rubrum
13
Q
epidemiology of tinea cruris
A
- usually caused by autoinoculation from tinea pedis
- men > women
- sweaty
- obesity/skin folds
- exacerbating factors: occlusive clothing; humidity
14
Q
clinical presentation:
- well-marginated, annular plaque with scaly raised border
- extends from the inguinal fold on the inner thigh
- pruritus and pain
- scrotum typically spared
- can be chronic and progressive
A
Tinea Cruris
15
Q
treatment for tinea cruris
A
- topical antifungals
- daily talcum powder
- avoid nystatin
16
Q
etiology of tinea pedis
A
trichophyton rubrum
17
Q
epidemiology of tinea pedis
A
- most common dermatophytosis worldwide
- risk factors: occlusive footwear, communal baths/showers/pools
18
Q
clinical presentation
- self-limited, intermittent, recurrent
- itchy/painful vesicles or bulla following sweating
- secondary staph infections common
A
tinea pedis
19
Q
clinical presentation
- slowly progressive, persists indefinitely
- erosions/scales between toes (esp 3rd and 4th)
- interdigital fissures
- sharp demarcation with accumulated scales in creases
A
chronic tinea pedis
20
Q
treatment for tinea pedis
A
- topical antifungal x 2 weeks
- oral meds for chronic/extensive disease (terbanfine, itraconazole, fluconazole)
- foot powder
21
Q
etiology of onychomycosis
A
- trichophyton rubrum
- trichophyton mentagrophytes
- candida albicans
- nondermatophyte molds
22
Q
epidemiology of onychomycosis? what organism usually affects toenails? fingernails?
A
- dermatophyte: usually toenails
- yeast: usually fingernails
- non-dermatophyte molds: rare
- risk factors: advanced age, tinea pedis, genetics, immunodeficiency
23
Q
clinical presentation
- typically starts with great toe, but all can be affected
- white, brown, yellow discoloration starts at distal corner and spreads towards cuticle
- distal end of nail breaks, exposing nail bed
A
distal subungual onychomycosis
- most common subtype
24
Q
clinical presentation
- white, brown, yellow discoloration starts near cuticle
- with what patient population is this condition usually seen?
A
proximal subungual oncychomycosis
- AIDS
25
clinical presentation
* dull, white spots on surface of the nail plate
* spread centrifugally until entire nail is involved
* can scrape the soft white areas for lab sample
white superficial onychomycosis
26
clinical presentation
* thickening of nail with yellow, brown discoloration
* may cause paronychia
* what is the etiology of this condition
* yeast onychomycosis
* candida albicans
* common cause of fingernail oncyhomycosis
27
treatment of onychomycosis
* not obligatory
* topicals generally ineffective
* high rates of failure/reoccurance
* treatment of dermatophyte onychomycosis: oral terbinafine (fingernails: 6 weeks; toenails: 12 weeks)
* treatment of nondermatophyte onychomycosis: oral itraconazole
* with these medications: keep eye on liver enzymes
28
what is intertrigo
* any infectious or noninfectious inflammatory condition of two closely opposed (intertriginous) skin surfaces
* often due to candida species
29
risk factors for candidal intertrigo
* moisture (humidity, incontinence)
* skin friction (obesity)
* immunocomprimised
30
clinical presentation
* erythematous, macerated plaques and erosions
* pruritus
* fine peripheral scaling
* **satellite** papules/pustules
* affects groin, mammary and abd folds, web spaces, axillae
candidal intertrigo
31
treatment for candidal intertrigo
* preventative: drying agent, weight loss
* topicals: Nystatin, Azoles
* Systemic: fluconazole, intraconazole
32
etiology of tinea versicolor (aka pityriasis versicolor)
* malassezia species: normal fungal skin flora that becomes pathologic when it transforms into the mycelial form
33
epidemiology of tinea versicolor
* 2-8% prevalence in US
* tropical climate
* adolescents/young adults
* risk factors: hyperhidrosis, malnourishment
34
clinical presentation
* macules, patches, plaques on trunk/UE
* hypopigmented, hyperpigmented, or erythematous
* varies with skin tone and location
* often have fine scale
* can coalesce
* typically asymptomatic
Tinea Versicolor
35
treatment of tinea versicolor
* topical: azole antifungals (ketoconazole) x 2 weeks
* systemic: extensive disease or failed topical: oral azole antifungals
36
Rosacea
* who is commonly affected
* 1-10% in whites
* high prevalence in fair-skinned
* females \> males
* usually emerges in 30s
37
clinical presentation
* chronic redness of central face
* flushing (wet or dry)
* telangiectasia
* skin sensitivity
* dry appearance
Erythematotelangiectatic rosacea
38
Clinical presentation
* papules and pustules of central face
* inflammation can be confluent
* no comedones (dilated hair follicle filled with debris: characteristic sign of acne)
papulopustular rosacea
39
Clinical presentation
* tissue hypertrophy causing irregular contours
* mostly nose by can involve cheeks, forehead and chin
* mostly affects men
phymatous rosacea
40
clinical presentation
* affects children and adults
* affects \>50% of those with rosacea
* dry eyes, pain, itching, blurry vision, photosensitivity, conjunctivitis, stye
ocular rosacea
41
treatment for erythematotelangiectatic rosacea
* behavior modification: avoid triggers, sun protection, gentle skin care
* laser and pulsed light therapies, topical brimonidine
42
treatment for papulopustular rosacea
* mild moderate: topical metronidazole
* mod-severe: oral tetracyclines or macrolides
43
treatment for phymatous rosacea
* early disease: isotretinoin
* advanced disease: surgical debulking
44
etiology of scabies
host-specific mite: sarcoptes scabiei
45
life cycle of scabies
* female mite excavates a burrow in the stratum corneum in which she lays 2-3 eggs/day for her 30 day lifespan
* eggs hatch in 10 days
* can live for 3 days away from host
46
clinical presentation:
* initial lesion
* burrow is pathognomonic
* common locations: back and head ofted spared
* severe pruritus, worse at night
scabies
47
treatment of scabies
scabicide
* permethrin 5% cream - initial tx + 2nd application 1 week later
* oral ivermectin
* fomite control
48
a large local reaction of a bee sting involved exaggerated erythema and swelling that gradually enlarges over 1-2 days and resolves in 5-10 days. What is the treatment?
* cold compress, prednisone, antihistamine, NSAID
49
what is the clinical presentation of a Widow spider bite
* local reaction: blanched circular patch, surrounding red perimeter and a central punctum
* venous causes catacholamine release: severe abd pain and muscle spasm, **local diaphoresis**, HA, N/V
* often cause few symptoms because no venom injected
50
treatment after widow spider bite
* antiemetics
* narcotic analgesics
* tetanus
51
Common clinical presentation of recluse spider bite
* often painless initially
* progress to severe pain in 2-8 hours
* resolves in a week
52
what is rare complication of a recluse spider bite
severe ulcerative necrosis
* dark, depressed center develops after 1-2 days
* systemic symptoms
53
acquired skin depigmentation thought to be from autoimmune process directed against melanocytes
clinical presentation:
* milk-white macules with homogenous depigmentation and well defined borders
* slowly progressive
vitiligo
54
treatment of vitiligo
repigmentation therapy
* topical and systemic corticosteroids
* UV light
55
pathogenesis of hidradenitis Suppurativa
1. follicular occlusion
2. follicular rupture
3. associated immune response
56
clinical presentation
* inflammatory nodules, sinus tracts, comedomes, and scarring
* commonly seen in axilla, inguinal, and anogenital regions
hidradenitis suppurativa
57
treatment of hidradenitis suppurativa
* topical clindamycin
* intralesional corticosteroids
* systemic abx: doxycycline
* surgery
