Dermatology Flashcards
Describe the lesions in psoriasis
scaly erythmatous well demarcated lesions on extensor surfaces, sacrum and scalp
Describe the lesions in guttate psoriasis
frequently triggered by a streptococcal infection. Multiple red, teardrop lesions appear on the body
What can exacerbate psoriasis
trauma
alcohol
drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
withdrawal of systemic steroids
What are some systemic signs of psoriasis?
pitting nails
arthropathy
Describe the stages in treatment of chronic plaque psoriasis
first-line: topical corticosteroid applied once daily plus vitamin D analogue applied once daily (applied separately, one in the morning and the other in the evening) for up to 4 weeks as initial treatment
second-line: if no improvement after 8 weeks then offer a vitamin D analogue twice daily
third-line: if no improvement after 8-12 weeks then offer either: a potent corticosteroid applied twice daily for up to 4 weeks or a coal tar preparation applied once or twice daily
short-acting dithranol can also be used
What are the complications of using topical corticosteroids in the treatment of psoriasis?
skin atrophy, striae and rebound symptoms
How long is the maximum amount of time corticosteroids should be used in the treatment of psoriasis?
potent corticosteroids for no longer than 8 weeks at a time
very potent corticosteroids for no longer than 4 weeks at a time
aim for a 4 week break before starting another course of topical corticosteroids
Give examples of vitamin d analogues
calcipotriol (Dovonex), calcitriol and tacalcitol
How do vitamin d analogues work?
reduce cell division and differentiation
they tend to reduce the scale and thickness of plaques but not the erythema
Why are vitamin d analogues preferable to corticosteroids or coal tar in the treatment of psoriasis?
adverse effects are uncommon
they may be used long-term unlike steroids
unlike coal tar and dithranol they do not smell or stain
What treatments can be used for extensive psoriasis?
phototherapy - UVB 3 times a week
What are the adverse effects of phototherapy?
skin ageing, squamous cell cancer (not melanoma)
What oral treatments can be used in psoriasis if disease is extensive or systemic?
first line: methotrexate
ciclosporin
systemic retinoids
biological agents: infliximab, etanercept and adalimumab
define purpura
red r purple area which does not blanch on pressure
due to bleeding into the skin or mucous membrane
define macule
flat area of altered colour
define patch
large flat area of altered colour
define papule
= solid raised lesion of <0.5cm diameter
define nodule
solid raised lesion of >0.5cm diameter with a deeper component
define plaque
palpable scaling raised lesion >0.5cm diameter
defin vesicle
raised clear fluid filled lesion <0.5cm diameter
define bulla
raised clear fluid filled lesion >0.5cm diameter
define wheal
transient raised lesion due to dermal oedema
define lichenification
well defined rougenign of skin with accentuation of skin markings
define crust
rough surface consisting of dried serum, blood, bacteria and cellular debris that has exuded through an eroded epidermis
define ulcer
loss of epidermis and dermis
define clubbing
loss of angle between posterior nail fold and nail plate
define koilonychia
spoon shaped depression of nail plate (anaemia)
onycholysis
separation of distal end of nail plate from nail bed (psoriasis)
pitting
punctate depression of nail plate
state the four layers of the skin
stratum corneum
stratum granulosum
stratum spinosum
stratum basale
What is the mechanism behind urticaria
local increase in permeability of capillaries and small venules due to histamine release from mast cells in response to allergen contact
what is the difference between uritcaria and angioedema
angioedema is swelling of the dermis and subcutaeous tissues,
uritcaria is swelling of the superficial dermis, which raises the epidermis
Describe anyphylaxis
bronchospasm
facial and layngeal odemea
hypotension
cellulitis
involves deep subcutaneous tissue
What are the suspicious features suggesting malignanct melanoma
Asymmetrical shape Border irregularity Colour irregularity Diameter >6mm Evolution of lesion Symptoms - bleeding/itching
What are the features of eczema
history of atopy
itchy, erythematous dry scaly patches
face and extensor surfaces in infants, flexor surfaces in children and adultsscratching or rubbing leads to lichenification adn excoriations
How is ecsema managed
avoid things that exacerbate
emollients
topical steroids or immunomodulators for flare up
antihistamines for itching
in severe cases wet wraps and oral ciclosporin may be used
How should emollients and topical steroids be applied
the emollient should be applied first
wait at least 30 minutes before applying the topical steroid
Describe the pathophysiology of psoriasis
chronic inflammatory skin disease due to hyperproliferation of keratinocytes and inflammatory cell infiltration
