Dermatology Flashcards
What is eczema herpeticum
HSV infection of eczematous skin
Who typically presents with eczema herpeticum
children and infants
What are the possible complications of eczema herpeticum
- blindness
- organ failure
- death
What is a differential for eczema herpeticum
impetigo
What is erythroderma
and inflammatory skin condition which causes red, hot painful skin covering 90% of the body
What type of patient is more likely to get eryhroderma
those with inflammatory skin disease eg psoriasis
How should erythroderma be managed
cool, wet dressings and emollients
What is erythema multiforme
a type 4 hypersensitivity reaction, usually to infection, that typically affects the palms and soles and has targetoid lesions
describe the signs you look for in erythema multiforme
targetoid lesions on the palms and soles, and sometimes haemorrhagic crusting on the lips
What usually causes erythema multiforme?
infection (>70% HSV)
What is the treatment for erythema multiforme?
- treat underlying cause
- give rehydration
- analgesics
What is the difference between Stevens-Johnson syndrome and Toxic epidermal necrolysis
TEN is the more severe form and covers >30% of the body
What % of the skin should be affected for a diagnosis of SJS
> 10%
What is SJS
A type 4 hypersensitivity reaction covering >10% of the body in macules, blisters or sheets of desquamation
Describe the changes that occur to the skin in SJS and TEN
macules form, then become blisters, then sheets of desquamation
What is Nikolsky’s sign? Is it positive or negative for SJS/TEN
Gentle rubbing of the skin causes desquamation
Positive in SJS/TEN
What causes SJS/TEN?
Change in medication
What is the management of SJS/TEN
Stop meds, monitor fluids, analgesics
What type of bacteria is most likely to cause skin infections?
gram positive (staph, group A strep)
What is impetigo?
A skin infection that causes bullae and honey-coloured crust
what usually causes impetigo?
staph aureus
What treatment should be given for impetigo?
hydrogen peroxide cream or topical antibiotic
What is staphylococcal scalded skin syndrome?
generalised form of impetigo causing a widespread, erythematous rash
what bacteria usually causes staphylococcal scalded skin syndrome?
staph aureus
What is erysipelas?
infection of the upper layer of the dermis and lymphatics
What does erysipelas look like?
erythematous lesion with clear demarcation
What is cellulitis?
infection of the deep dermis and subcut tissue
What does cellulitis look like?
Fast-spreading erythematous lesion with indistinct margins
what is the visual difference between cellulitis and erysipelas
erysipelas has clear demarcation of the lesion whereas cellulitis has indistinct borders
What should be given to treat cellulitis or erysipelas
anitbiotics
What is a skin abscess?
A walled-off infection with a collection of pus
What is atopic dermatitis?
eczema
What is eczema
a pruritic rash on flexor surfaces and exposed skin (eg face) caused by type I hypersensitivity reaction
Where would areas of eczema be found?
flexor surfaces (eg backs of knees, insides of elbows) exposed skin (eg face and hands)
What is the treatment for eczema
emollients and moisturisers
- topical corticosteroids can be used in acute flare ups
why are topical corticosteroids not suitable for long term use in eczema
they will cause skin atrophy
What are the three most common types of leg ulcers?
- venous ulcers
- arterial ulcers
- neuropathic ulcers
What type of leg ulcer is common in diabetes
arterial/neuropathic
What other types of leg ulcers apart from venous, arterial, and neuropathic ulcers, might you get
- pyoderma gangrenosum
- infectious cause (eg syphillus)
- malignant cause
What causes venous ulcers
venous valve incompetence causes blood stasis which increased blood pressure in the veins, leading to compression and ischaemia which causes tissue death
What kind of ulcers might you see in venous ulcers? where?
shallow, mildly painful ulcers
found in the gaiter area
What is the gaiter area? what type of leg ulcers are commonly found there?
the area on the leg above the medial maleolus
venous leg ulcers
What other findings might you find on inspection of the leg in venous ulceration
- varicose veins
- oedema
- brown discoloured skin
What are some risk factors for venous ulceration
- old age
- female
- pregnant
- obese
What treatment is used for venous ulceration
- compression bandages
- elevation
- possibly surgery
What causes arterial leg ulcers
peripheral vascular disease causes ischaemia in the leg which causes tissue death, resulting in ulceration. Usually ulcers result from small wounds that don’t heal
What other signs might point towards arterial ulceration?
- cold limb
* pulseless
Where are arterial ulcers commonly found?
On bony prominences eg the heel or the toe
What is treatment for arterial ulcers
Surgical revasculisation
What is neuropathic ulcer?
peripheral neuropathy causing loss of sensation which may result in ulcers on pressure points (eg the sole of the feet) going unnoticed and presenting late
What is the main cause of neuropathic ulcer>
diabetes mellitus
Describe what the ulcers usually look like in neuropathic ulcer
What is a distinctive characteristic
They are “punched out” and painless
What is pyoderma gangrenosum
an inflammatory and ulcerating skin condition usually caused by an underlying condition eg inflammatory bowel disease/arthritis
It is a diagnosis of exclusion
What is psoriasis
an inflammatory condition of the skin which causes itchy or painful plaque formation with ‘silvery scales’ on extensor surfaces and around scalp and trunk
Where are classic locations for psoriatic plaques?
- scalp
- trunk
- buttocks
- extensor surfaces (eg elbows)
What is koebner’s phenomenon?
psoriatic plaque at sign of trauma
What is Auspitz’s sign?
removal of the top of a psoriatic scale will reveal pinpoint bleeding
What signs might be noticed on the hands in psoriasis?
- plaques
- joint swelling
- nail pitting
What other condition can occur with psoriasis
psoriatic arthritis
What is first line treatment for psoriasis?
emollients and topical corticosteroids
What is second- and third- line treatment for psoriasis
- systemic biologics
- systemic non-biologics
- phototherapy
What systemic non- biologics can be given for psoriasis
- methotrexate
- cyclosporine
- Acitretin
What systemic biologics can be given
TNFa-inhibitors:
- adalimumab
- etanercept
- infliximab
anti-interleukin agents
* brodalumab
What is found on exam of acne vulgaris?
- erythematous papules, pustules, cysts and nodules commonly on the trunk and face, sometimes with scarring
What happens to the skin in acne vulgaris?
- plug formation of dead keratinocytes
- sebum overproduction
- bacterial colonisation
What is a whitehead
a closed comedone
What is a blackhead
an open comedone
What factors can worsen acne?
- androgen (eg puberty)
* products that block pores
How do androgens worsen acne
Increase sebum production
What conditions are associated with acne vulgaris
- PCOS
- cushing’s
- congenital adrenal hyperplasia
How is acne treated?
- topical retinoids
- topical antibiotics
- oral antibiotics
- isotretinoin
What age of patient is most common for acne rosacea
adults
What might be found on exam in rosacea?
- erythematous face
- blushing
- telangiectasis
- papules and pustules
What non-skin findings might be found in rosacea
ocular involvement
- conjunctivitis
- telangiectasis on eyelids
How common is ocular involvement in acne rosacea
> 50%
What might exacerbate rosacea
- spicy foods
- alcohol
- heat
- sun exposure
Give a differential for acne rosacea
lupus erythematosus
What lifestyle advice can be given for rosacea
- avoid spicy food/ alcohol
* use sunblock and avoid sun exposure
What treatment can be given for rosacea
- topical brimodine (an alpha-adrenergic agonist)
What are small blisters called
vesicles
what are large blisters called
bullae
give some examples of generalised blistering skin disorders that do not cause systemic symptoms
- pemphigoid
- bullous impetigo
- dermatitis herpetiformis
What is pemphigoid
And autoimmune blistering skin reaction
give some examples of generalised blistering skin disorders that do cause systemic symptoms
- disseminated herpes zoster (chickenpox)
- SJS + TEN
- scalded skin syndrome
- paraneoplastic pemphigoid
Give some examples of localised blistering skin disorders
- contact dermatitis
- erythema multiforme
- herpes zoster
- friction blisters
- HSV
What is urticaria also known as
hives
What duration is acute uritcaria
<6 weeks
Describe urticaria in appearance
red, raised, itchy rash
What duration is chronic urticaria
> 6 weeks
What are the types of chronic urticaria
- spontaneous urticaria
- autoimmune urticaria
- inducible urticaria
describe inducible urticaria
rash can be induced by physical stimuli
What treatment can be given for acute urticaria
antihistamine or topical corticosteroids
What usually causes acute urticaria?
allergic reaction
What are the three main types of skin cancer?
- squamous cell carcinoma
- basal cell carcinoma
- melanoma
What cells cause basal cell carcinoma
cells in the stratum basale
Describe the appearance of basal cell carcinoma
Typically a pearly nodule with a raised, red, edge
Can be plaque-like, may be shiny, may not be raised
What is the treatment for basal cell carcinoma
excision
What is squamous cell carcinoma
cancer of the squamous cells of the epidermis
Describe the appearance of squamous cell carcinoma
A hard, scaly dome like lesion that is often eroded at the centre
How is squamous cell carcinoma easily differentiated from a wart
typically larger and may be painful
What is the precursor to squamous cell carcinoma called
actinic keratosis
What is the name for squamous cell carcinoma in situ
Bowen’s disease
What is the treatment for squamous cell carcinoma
excision
What should you look for in examination of a mole?
Asymmetry Borders Colours Diameter Evolution/enlargement
What about a mole’s borders would concern you on examination?
Irregular borders
What colouration of a mole would concern you?
multiple colours
What is alopecia areata?
A chronic autoimmune non-scarring hair loss disorder
What does presentation in alopecia areata look like?
discreet circular patches of hairloss without pain or itchiniess
What other non-hair signs might be found in alopecia areata
nail bedd pitting
What conditions are associated with alopecia areata
other autoimmune conditions
What might happen to the disorder in alopecia areata?
hair may grow back or may proceed to alopecia totalis
what is erythema nodosum
painful erythematous nodular lesions on the anterior shins
What might cause erythema nodosum
- sarcoidosis
- drugs
- bacterial infection
What is erythema marginatum?
pink coalescent rings which come and go on the trunk
what is erythema marginatum associated with
rheumatic fever
What is erythema chronicum migrans also described as
bulls eye mark
what is erythema chronicum migrans a sign of?
Lyme disease
what are common associated with vitiligo?
organ specific autoimmune conditions
What is pyoderma gangrenosum
nodule or pustule ulceration
what is pyroderma gangrenosum associated with
- UC + crohn’s
* RA
What skin manifestations might you find in crohn’s disease
- perianal/vulval ulcers
- pyoderma gangrenosum
- erythema nodosum
What skin manifestation might you see of coeliac’s
dermatitis herpetiformis
a very itchy erythematous rash
Describe pretibial myxoedema
red oedematous discolouration of the shin
What condition causes pretibial myxoedema
hyperparathyroidism
what is acanthosis nigricans
pigmented rough skin in axillae or groin
what is acanthosis nigricans associated with
stomach cancer
what might cause cutaneous vasculitis?
- drugs
- serum sickness
- infection
What might patients present with in cutaneous vasculitis
- purpura
- petechiae
- urticaria
- shallow ulcers
- nodules
