Psoriasis Flashcards
What is psoriasis?
A chronic inflammatory skin disease due to hyper-proliferation of keratinocytes and inflammatory cell infiltration
Describe the features of psoriasis
Scaled
Erythematous plaques
Silvery appearance
Lesions may be itchy, burning or painful
Common on the extensor surfaces and over the scalp
Auspitz sign- scratch and gentle removal of scales causes capillary bleeding
50% also have nail changes- Pitting or onycholysis
5-8% suffer associated psoriatic arthropathy
What is auspitz sign?
Gentle scratching away of scales causes capillary bleeding
What nail changes are seen in psoriasis?
Pitting
Onycholysis
What is the most common type of psoriasis?
Chronic plaque psoriasis
What is post-streptococcal guttate psoriasis?
Derived from gutter meaning droplet- Raindrop lesions
Truncal distribution of widespread small plaques
Commonest in children
Occurs 2 weeks post group A beta haemolytic strep infection (pharyngitis/tonsillitis)
Usually self limiting
Around 40% develop chronic plaque psoriasis
What is palmar-plantar pustular psoriasis?
Affects the palmar and plantar surfaces (palms and soles)
Majority of patients are women (9:1) and around 25% also have chronic plaque psoriasis. It is associated with thyroid disease.
What systemic issues can also occur with psoriasis?
Seronegative spondyloarthropathy- psoriatic arthritis
Nail psoriasis
Associated with anterior uveitis and episcleritis
Associated with Crohn’s Disease and Ulcerative Colitis
Psychological impact
Roughly what percentage of patients have nail changes in psoriasis?
Around 50%
Features are pitting and onycholysis
What are the features of psoriatic arthritis? What percentage of patients are affected?
Inflammatory arthritis
Classically involves DIPS
End stage is Arthritis Mutilans- Severe flexion deformity of DIP
Symmetrical polyarthritis, asymmetrical oligomonoarthritis, psoriatic spondylosis
What makes patients with psoriasis more at risk of CVD?
They are at increased risk of metabolic syndrome: Hyperglycaemia Hyperlipidaemia Central obesity Insulin resistance Hypertension
What are the features of type I psoriasis?
Generally age of onset <40
HLA-Cw6 65% (association)
What are the features of type II psoriasis?
Generally age of onset >40
HLA-Cw6 15% (no association)
What is thought to cause psoriasis?
Complex interaction between genetic, immunological and environmental factors.
Disease is now thought to be due to immune dysfunction and be T-Cell mediated.
Precipitating factors include trauma (may produce Koebner phenomenon), infection (e.g post-streptococcal guttate psoriasis), drugs, stress, alcohol
What are some known triggers for psoriasis?
Streptococcus Infection- Guttate Psoriasis, and patients with chronic plaque psoriasis can get flares with infection
HIV
Trauma- Koebner Phenomenon
Drugs- Beta blockers, NSAIDs, Lithium, Anti-Malarials
What are the differential diagnoses for scaly skin lesions?
Psoriasis Eczema Fungal infection Cutaneous T-Cell Lymphoma/Mycosis Fungoides can appear like psoriasis, asymmetrical- do a biopsy Wide spread SCC Actinic Keratosis
What should you explain to patients recently diagnosed with psoriasis?
What is known about the disease
It is not contagious
Can come and go
Treatment is suppressive
What scoring system is used to gauge the severity of psoriasis?
PASI- Psoriasis Area and Severity Index
What are some of the features of mild psoriasis?
Disease is limited- less than 10% of BSA
May remit spontaneously
Stable disease
Rarely requires continuous therapy
Most commonly managed in primary care.
What are the first line measures for the management for psoriasis? (For mild and localised psoriasis)
General Measures- Avoid known precipitating factors, emollients to reduce scales.
Topical Therapies- Coal tar preparations, Dithranol (inhibits keratinocyte proliferation). Vitamin D Analogues, Topical corticosteroids, topical retinoids, keratolytics and scalp preparations
How does dithranol work?
This is a topical treatment for psoriasis that reduces keratinocyte proliferation
Side effects- skin irritation (burning), stains skin and clothes
How are vitamin D analogues used in the management of psoriasis?
Topical treatment that stabilises keratinocyte proliferation
Given as creams or ointments e.g:
Calcipotriol, Tacalcitol, Calcitriol
Side effects- skin irritation, hypercalcaemia if widely used..
May be combined with corticosteroids
What are some side effects of topical corticosteroids given for the management of psoriasis?
Skin atrophy
Cushing’s Syndrome if used widely
Unstable psoriasis - pustular
May be used as creams, ointments, lotion. Often combined with vitamin D analogues to reduce the side effects.
What are some features of severe psoriasis?
Greater than 10% of BSA affected
Persistent with frequent plares
Unresponsive to initial topical therapies (coal tar, dithranol, corticosteroids, vit D)
Often requires life long treatment
