Dermatology Flashcards
Which diagnostic preparation can help distinguish eczema from a tinea infection?
KOH prep
What is the risk of using too many steroids on the skin?
Skin atrophy
What type of reaction is atopic dermatitis?
Type IV hypersensitivity
What are common causes of atopic dermatitis?
poison ivy
nickel
topical abx
What type of allergy is latex?
Type I hypersensitivity
What is seborrheic dermatitis?
Chronic inflammatory to Malassezia furfur
What is the treatment of seberrhoic keratosis?
Selenium sulfide or zinc pyrithione shampoos
What is stasis dermatitis?
Lower extremity dermatitis due to venous HTN
What is the treatment of venous stasis?
Leg elevation
Compression stockings
Emollients
Topical steroids
What is the Koebner phenomenon?
Trauma from psoriasis
What is Auspitz sign?
Pinpoint bleeding when a psoriasis scale is scraped
Histogically what is seen in a psoriasis biopsy?
Thick epidermis Elongated rete ridges Absent granular cell layer Preservation of nuclei in the stratum corneum Sterile neutrophilic infiltrate
How do you treat psoriasis -
Mild?
Severe form?
Steroids topical
Methotrexate
anti TNF
UV light therapy if very severe
What causes urticaria?
Histamine and PG from mast cells in a Type I hypersensitivity
What is the treatment of urticaria?
systemic antihistamines
When does a drug eruption happen?
7-14 days after exposure.
If it occurs within 1-2 days of starting a new drug it is likely not the causative agent
What are the characteristic lesions of erythema multiforme?
Targenoid lesions
What is Stevens-Johson Syndrome?
Life threatening exfoliative mucocutaneous disease
What is the difference between SJS and TEN?
Epidermal seperation < 10% SJS BSA
Epidermal seperation > 30% TEN BSA
In which illness is Nikolsky sign positive?
SJS
TEN
What are some causes of SJS?
Penicillin Sulfonamide Seizure medication Allopurinol Cephalosporins Radiotherapy
What is erythema nodosum caused by?
Infection: streptococcus, coccidiodes, yersinia, TB
Drug reaction: OCP, abs, sulfonamide
Which number is oral herpes?
HSV-1
Which number is oral herpes?
HSV-2
What is the treatment ofHSV?
Acyclovir
No multinucleate giant cells on Tzanck smear?
Tzanck goodness it’s not herpes
What is the incubation period of VZV?
10-20 days
When does VZV become contagious ?
24 hours before the eruption appears
What are some complications of VZV?
Pneumonia
Encephalitis
What is molluscum contagiosum caused by?
Poxvirus
How does molluscum contagiosum present?
Flesh coloured
Dome shaped
Wax papule
What is the treatment of molluscum contagiosum?
Curettage
Freezing
Trichloroacetic acid
Which forms of HPV can progress into squamous malignancies?
16 and 18
Which infection is caused by group A strep and staph?
Impetigo
What is impetigo?
Infection of the epidermis
Symptoms of Necrotising Fasciitis
Erythema rapidly spreading over the course of hours-days
Pain and swelling
Necrosis: gas production, putrid discharge, bull, pain
Treatment of Necrotising Fasciitis
Surgical emergency : surgical debridement
Abx: penicillin G
Which organism causes hot tub folliculitis?
Pseudomonas
What is the treatment of mild to moderate acne?
topical retinoid
Topical benzoyl peroxide
Moderate to severe acne treatment?
Abx
if all treatment have failed: oral retinoid
What is the presentation of tinea versicolor
Hypo pigmentation
Varying colour
Chest and back
What does a KOH prep of tinea versicolor reveal?
spagetthi and meatballs
What is seen on biopsy of SJS?
Full thickness eosinophilic epidermal necrolysis
Treatment of vitiligo?
Sun avoidance/protection
Topical calcineurin inhibitor
PUVA NB UVB
What does HSV look like on Tzanck smear?
Multinucleated giant cells
Most accurate way to diagnose HSV?
viral culture or PCR
What is the treatment of molluscum contagiosum?
Cantharidin
Cryotherapy
Currettage and freezing
Self limiting, can take 1 - 2 years to resolve
What is the first line treatment of warts?
Salicylic acid prep
Cryotherapy
Topical cantharone
What is the second line treatment of warts?
Topical imiquamode
5-fluorouracil
podophyllotoxin
What is the 3rd line treatment of warts?
Currettage
Cautery
Surgery for non plantar
CO2 lazer
What is the first line treatment of warts?
Salicylic acid prep
Cryotherapy
Topical cantharone
What is the second line treatment of warts?
Topical imiquamode
5-fluorouracil
podophyllotoxin
What is the 3rd line treatment of warts?
Currettage
Cautery
Surgery for non plantar
CO2 lazer
Treatment of impetigo?
Mupirocin 2% cream
Fusinic acid
All this 7-10 days after resolution
Treatment of tinea capitis?
Terbinafine
Clinical signs of tinea capitis?
Round scaly patches of alopecia
What is the pathophysiology of actinic keratosis?
UV radiation damages keratinocytes
UV induced p53 mutation
Treatment of scabies
Permethrin 5% from the next down x2 treatment 1 week apart
Wash underwear/linen x2 in hot water cycle and machine dry
Treat family and close contact
Treatment of Lice
Permethrin 1%
Comb hair with dilute vinegar solution to remove nits
Repeat in 7 days
Shave hair, change clothes, wash and machine dry
Treatment of actinic keratosis?
Destruction:
- cryotherapy, electrodessication, curettage
Pharmacotherapy topical
- topical 5FU cream
- Imiquimod 5%
If refractory to treatment: biopsy
What does actinic keratosis look like?
Scaly plaques on sun damaged areas
At what age to infantile hemangioma’s disappear?
9mo to 1 yo
