Psoriasis Flashcards
What is Psoriasis?
Chronic, genetically determined, immune-mediated, inflammatory skin condition, usually characterized by typical well defined, scaly, plaques
It can also involve nails, hair and joints
Skin condition associated with patches of abnormal skin
what is the epidemiology of psoriasis?
Affects 3% of UK population, M=F
Peak incidences - 20’s, 50’s
Uncommon in Far east population, Native Americans, West Africans
> 1/3rd have a family history, rising up to > 2/3 of cases presenting with psoriasis before 20 years of age
Around 5% develop psoriatic arthritis
Psychosocial implications
Systemic disease, link to metabolic syndrome and cardiovascular disease
what does psoriasis look like and where does it effect?
Red scaly plaques
Often symmetrical distribution
Chronic plaque
Flexural
Acute Guttate (resembling drops or characterized by markings that resemble drops)
Scalp
Palmoplantar
Nail
Pustular
Erythrodermic
What causes and how does psoriasis happen in the body?
Overactivity of the immune system
Excessive production of TH1 Cytokines inc TNF-alpha
Vascular proliferation (erythema), increased cell turnover (plaques and scaling)
what are the causes of psoriasis?
Genetics
Environmental
Infection - Strep, Candida
Drugs - Lithium, Beta-blockers, NSAIDS, Steroid withdrawal
Trauma – Koebner phenomenon (spread with trauma)
Sunlight
what is the pathogenesis of psoriasis?
Epidermal infiltration by activated T cells:
Increased epidermal cell proliferation & turnover - cell cycle reduced from 28 days to 3-5 days; capillary angiogenesis
Excessive production of TH1 cytokines esp TNF-alpha
Increased TNF-alpha linked to flares
what are the genetics involved with psoriasis?
Family history
1 parent has psoriasis = 14% of child developing
Both parents have = 41% chance
HLA Cw6, B13, B17
what are the precipitants of psoriasis?
Trauma, Infection, Drugs (B-blockers, Lithium), Sunlight, Stress, Cigarettes & Alcohol, HIV
what does histology in psoriasis look like?
Hyperkeratosis (thickening of stratum corneum) with parakeratosis (keratinocytes with nuclei in stratum corneum)
Neutrophils in stratum corneum (munro’s microabcesses)
Hypogranulosis: no granular layer (needed for barrier function)
Psoriasiform hyperplasia: Acanthosis (thickening of squamous cell layer) with elongated rete ridges
Dilated dermal capillaries
Perivascular lymphohistiocytic infiltrate; T cell infiltration
subtypes of psoriasis
54 year old male presents with a 15 year history of scaly plaques on both elbows. Over the last few months the rash has spread to involve large areas of his body
He has recently lost his job and has been diagnosed with hypertension
O/E he has large salmon coloured plaques on his arms, legs and back with thick scale
what is it?
Chronic Plaque Psoriasis
Chronic plaque psoriasis accounts for almost ___ of psoriasis cases
90%
In chronic plaque psoriasis severe cases with bigger plaques have stronger impact on what?
Severe cases with bigger plaques have stronger impact on psycho-social and cardio-vascular health
chronic plaque psoriasis is normally managed with what?
Commonly managed with topical treatments in primary care setting
A 14 year old boy presents with an acute onset of a generalized eruption
O/E he has 2-5 mm multiple salmon colour papules with a fine scale worse on the trunk and proximal extremities
On direct questioning his mother says that he has had a throat infection 2-3 weeks prior to the rash
what is it?
Guttate psoriasis
What is Guttate psoriasis?
Guttate psoriasis is a type of psoriasis that shows up on your skin as red, scaly, small, teardrop-shaped spots. It doesn’t normally leave a scar. You usually get it as a child or young adult. Less than a third of people with psoriasis have this type. It’s not as common as plaque psoriasis
Guttate psoriasis commonly occurs when?
post-viral
A 32 year old lady presents with several months’ history of a rash on her hands and feet. She works as a beautician/masseuse and wants it to be cured
O/E the skin on the palms and soles appears thick, scaly and red with yellowish brown lesions at the edges
what is it?
Palmo-plantar Psoriasis
27 year old lady presents to your clinic complaining of severe dandruff. She has tried various shampoos with out much effect. She has noticed that the dandruff is spreading on to her face as well
O/E you note thick hyperkeratotic plaques in the scalp with some pitting of the nails. She also has 2 small plaques of scaly rash on the cheeks
what is it?
Scalp Psoriasis
D/D – Seborhoeic dermatitis
- Nail Psoriasis
36 year old patients presents to you complaining of several months history of rash in his armpits. He has been treated with topical and oral anti-fungal agents in the past with out any benefit. Skin scrapings show no growth
O/E you note shiny pink to red sharply demarcated plaque with no scaling
what is it?
Flexural/Inverse Psoriasis
50 year old lady presents with an acute onset of generalised red, tender patches. On closer inspection of the patches multiple yellow pustules are seen
what is it?
Pustular Psoriasis
67 year old patient with 35 years history of Chronic plaque psoriasis. His wife recently died and because his psoriasis started to flare up he was prescribed 2 weeks course of oral Prednisolone. He presents 4 weeks after that feeling generally unwell.
O/E He has generalized erythema of the skin with fine scale. He is pyrexial and has low blood pressure
what is this?
Erythrodermic psoriasis
‘Red Man’ syndrome
What are some differential diagnosis of psoriasis?
Seborrhoeic dermatitis (Esp Scalp, face)
Lichen planus (Check forearm, oral mucosa)
Mycosis fungoides (older Pt, Sudden onset of plaques or treatment resistant plaques – Think of biopsy)
