Dermatology Flashcards
what is Auspitz sign?
it is seen in psoriasis when pinpoint bleeding occurs on removal of a layer of scale
what is Koebner phenomenon?
where skin lesions in psoriasis occur at sites of skin injury in otherwise healthy skin
what is eczema herpeticum caused by?
herpes simplex virus
what is the treatment of eczema herpeticum?
IV aciclovir
what are the situations for using:
- patch testing
- skin prick testing
- skin scrapings
- identify allergens that cause a type 4 hypersensitivity reaction - takes 2 days for a reaction
- identify allergens which cause a type 1 hypersensitivity reaction (IgE antibodies) e.g. asthma or anaphylaxis
- when fungal infection is suspected
which organism is seborrheic dermatitis associated with?
malassezia fungus
what is the treatment of infantile seborrheic dermatitis?
topical olive oil
which condition is acne vulgaris associated with?
PCOS - polycystic ovarian syndrome
what are the treatments for acne vulgaris?
- conservative
- salicylic acid and benzoyl peroxide
- topical retinoids
- Abx - tetracyclines and erythromycin/clindamycin
- systemic: anti-adrenergic like OCP and spironolactone
- isotretinoin
what is the problem with retinoids?
they are teratogenic
what are the complications of acne rosacea?
rhinophyma (skin thickening, enlargement and disfiguration of the nose)
blepharitis, conjunctivitis, keratitis
what is the treatment of acne rosacea?
general: sun protection, avoid spicy foods
emollients
topical: Abx = metronidazole; azelaic acid, brimonidine…
laser therapy for telangiectasia
surgery for rhinophyma
which mite is commonly found in sebaceous follicles of individuals with rosacea?
demodex folliculorum
what lesions can herpes simplex cause?
oral lesions genital lesions aphthous ulcers herpes keratitis herpetic whitlow
what are the investigations for herpes simplex?
usually clinical diagnosis
swab for HSV NAAT (PCR test)
what is the treatment of herpes simplex?
aciclovir
what is the advice for patients who have ongoing herpes simplex?
sex should be avoided when there is a prodrome and or genital lesions are present
what are the 3 major signs of chicken pox?
rash, fever and malaise
which organism causes chicken pox?
varicella zoster virus
how long does prodrome in chicken pox last?
up to 4 days
how do you know when chicken pox is not contagious anymore?
the lesions have crusted over
what is the treatment for chicken pox?
hydration, avoid scratching, avoid high-risk groups
paracetamol
sedating antihistamines (chlorphenamine) for itch
emollients and calamine lotion for itch
oral aciclovir if severe or high-risk group
which drug should not be given with chicken pox?
NSAIDs!!!
which organism causes shingles?
varicella zoster virus
what is the presentation of shingles?
dermatomal distribution - never crosses the midline pain rash - vesicular, fluid-filled can be a/w flu-like symptoms can involve the eye
what is Ramsey-Hunt syndrome?
facial nerve involvement with the varicella zoster virus
this leads to skin lesions in the ear, hearing and vestibular problems and facial paralysis
what is the treatment of shingles?
oral antivirals - valaciclovir
which organism causes molluscum contagiosum?
poxvirus
what is the presentation of molluscum contagiosum?
lesions are small, smooth, pearly coloured papules with a central area of umbilication
which organisms cause impetigo?
STAPH AUREUS!!
also strep pyogenes
which organisms cause cellulitis?
group A- beta haemolytic strep - strep pyogenes
staph aureus
less common: strep pneumonia haemophilus influenza gram negative bacilli anaerobes MRSA
what type of infection is a dermatophyte?
fungal infection
what is another name for dermatophyte?
tinea or ringworm
where are the following located?
- tinea capitis
- tinea pedis
- tinea cruris
- tinea corporis
- onychomycosis
- scalp
- foot (athlete’s)
- groin
- body
- fungal nail infection
what is the most common dermatophyte?
trichophyton rubrum
what increases the risk of tinea?
occlusive footwear, excess sweating…
use of steroids
diabetes
immunosuppression
what are the presentations of tinea corporis, tinea capitis and tinea pedis?
tinea corporis: itchy rash, scaly, red, well-demaracted rings
tinea capitis: well-demarcated hair loss; itchy, dry, red
tinea pedis: white/red, flaky, cracked, itchy between toes
what investigations are needed for tinea?
skin scrapings - microscopy and culture
what is the management of tinea?
general: hygiene, footwear, don’t share clothing…
topical anti-fungals: terbinafine, clotrimazole, miconazole (both creams), ketoconazole (shampoo)
oral anti-fungals: terbinafine, fluconazole, itraconazole
for a fungal nail infection: amorolfine nail laquer 6-12 months; if resistant = oral terbinafine
what do you need to check when giving oral terbinafine for tinea?
need to check LFTs
what is the most common candidiasis?
candidiasis albicans