Psoriasis Flashcards
What is psoriasis
widespread inflammatory condition characterised by widespread well-demarcated erythematous plaques covered with a silvery layer on top
what is the histological change in psoriasis
thickening of the epidermis with some lymphocytic infiltration
what’s the chance of inheriting psoriasis if one parent has it, or if both have it
1 parent 25%
both 60%
what group of genes are responsible for psoriasis
HLA
what age does psoriasis commonly present at
double peak, so mid teens then again in 50s
what is the difference in presentation of a younger patient from an older one in psoriasis
younger tends to be stronger family history with more severe symptoms
what are the types of psoriasis
chronic plaque - most common palmoplantar flexural guttate erythrodermic pustular
what is the most common type of psoriasis + what proportion of all types does it take up
chronic plaque - 60%
what are some features of chronic plaque psoriasis
widespread well-demarcated erythematous plaques with overlying scale mainly on scalp sacrum and extensor compartments of limbs
sometimes itchy + bleed when scale removed
what is auspitz sign
bleeding on removal of scale for psoriasis - not clinically performed
what can psoriasis sometimes be confused for + how do you tell them apart
seborrhoeic dermatitis or dandruff as it it mostly found on scalps
psoriais is thicker, better demarcated and scalier
what proportion of those with chronic plaque psoriasis have the associated nail changes
50%
what are the associated nail changes with psoriasi
pitting
subungal hyperkeratisation - build up of keratin beneath distal nail edge
onycholysis - separation of nail from bed causing a colour change
what are features of palmoplantar psoriasis
psoriasis affecting the soles of the feet and the palms of the hands - usually yellow/brown pustules on hand/feet only
usually less erythema and just thickening
who is more likely to get palmoplantar psoriasis
female smokers
what is flexural psoriasis
psoriasis affecting the flexural areas of the body - axilla, submammary areas, natal cleft
plaques tend to be smooth and glazed due to friction in flexural areas
may coexist with chronic plaque
who is more likely to get flexural psoriasis
elderly people
what can be associated with flexural psoriasis
yeast/bacteria infection on top
what is erythrodermic psoriasis
confluent psoriasis covering around 90% of the bodys surface - dermatological emergency
what may cause erythrodermic psoriasis
withdrawal of potent steroids
drug eruptions
what is the complications for erythrodermic psoriasis
hypothermia dehydration sepsis protein loss high output cardiac failure
what is pustular psoriasis
rare but life-threatening form with 2 subtypes- generalised and local
generalised: acute onset sheets of pustules on background of erythema, skin is painful, spread is rapid, onset is acute, patients is systemically unwell, required hospital admission
local: Palmoplantar psoriasis, older age of onset, sore pustules but no systemic symptoms – strongly associated with smoking
what is acrodermatitis of hallopeau
uncommon form of pustular psoriasis affecting fingers and nails
what are the systemic complications of psoriasis and what % suffer from them
10% have arthritis, 5% have psoriatic arthritis
There is a higher chance of ankylosing spondylitis and sacrolitis
arthritis mutilans
what is arthritis mutilans
This is the development of small erosions in the small bones of hands, feet and spine, causing progressive deformity due to damage causing things like telescoping of the fingers
what are common triggers for psoriasis
streptococcal throat infection stress medication (beta blockers, anti malaria medication, lithium) alcohol smoking trauma sunlight (but only 10% of patients)
what is the general treatment for psoriasis
Stepwise
- topical treatment + specialist referral
- phototherapy
- non biological systemic therapy
- systemic biological therapy
what topical treatments are used for psoriasis treatment
Emollient
Vit D3 analogue – may lead to hypercalcaemia, restricted to 100g p/w
Corticosteroid (hydrocortisone, eumovate, betonate, dermovate (in order of strength)) - most commonly used, great for plaque, facial and flexural psoriasis. Only hydrocortisone and eumovate allowed on face in adults, only hydrocortisone in kids unless done by a specialist)
Keratolytic (5% salicylic acid – mainly used against thick plaques)
Coat Tar – mainly used in guttate psoriasis, but messy and restricted to OPC use
Dithranol (short contact time) - messy, causes staining, only used in plaque psoriasis, causes irritation
what phototherapy is used in psoriasis
PUVA - topical photosensitising agent + UVA
UVB
what are the side effects of photosensitising agents
erythema
pruitis
nausea
skin cancer
what non-biological systemic treatments are used for psoriasis
methotrexate
ciclospirin
aceitretin
what is methotrexates mechanism of action
folic acid antagonist selecting for rapidly dividing cells
what are some side effects of methotrexate
GI upset
teratogenicity
nausea
liver/lung fibrosis
what is the method of action for ciclosporin
suppresses T lyphocytes and lymphokine production
what are side effects of ciclosporin
hypertension
nephrotoxicity
carcinogenesis
what is an important counselling point for aceitretin
causes teratogenicity for 2 years post treatment - not used in women planning to have a family too
what is used for systemic biological therapy for psoriasis
infliximab
