Psoriasis Flashcards
What is psoriasis?
Common (2%) chronic skin disorder. Presents with red, scaly patches on the skin.
What diseases are patients with psoriasis at increased risk of?
Arthritis
Cardiovascular disease
What is the pathophysiology of psoriasis?
Multifactorial
Genetic component: Associated HLA-B13/B17/Cw6.
Immunological: Abnormal T cell activity stimulates keratinocyte proliferation.
Environmental: May be worsened by skin trauma, stress, streptococcal infection.
(Improved by sunlight)
What are the subtypes of psoriasis?
Plaque psoriasis: most common
Flexural psoriasis: smooth skin
Guttate psoriasis: transient psoriatic rash triggered by a streptococcal infection ‘tear-drop’ lesions
Pustular psoriasis: palms and soles
Where does plaque psoriasis most commonly effect?
Extensor suraces, sacrum and scalp
What are the additional features of psoriasis?
Nail signs: pitting, onycholysis
Arthritis
What are the complications of psoriasis?
Psoriatic arthropathy (10%)
Increased incidence:
Metabolic syndrome
Cardiovascular disease
Psychological distress
What are exacerbating factors of psoriasis?
Trauma
Alcohol
Drugs: Beta-blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs, ACE inhibitors, infliximab
Withdrawal of systemic steroids
Streptococcal infection may trigger guttate psoriasis.
What is the management of psoriasis?
Regular emollients
1st line: Potent corticosteroids once daily + vitamin D analogue applied once daily (one AM one PM)
2nd line: vitamin D analogue TD
3rdd line: potent corticosteroid TD or Coal tar preparation OD or TD
Short acting dithranol
What are the recommendations in topical steroid use in psoriasis?
Sfx: skin atrophy, striae, rebound symptoms
Systemic side-effects if potent steroids used on large area
Aim for a 4-week break before starting another course of topical corticosteroids
Potent no longer than 8-weeks at a time, very potent no longer than 4-weeks at a time
What is an example of Vitamin D analogues which can be used to treat psoriasis?
Calcipotriol (Dovonex)
Calcitriol
Tacalcitol
How do vitamin D analogues work?
Reducing cell division and differentiation
Few side-effects, may be used long-term, don’t smell or stain, reduce scale and thickness of plaques but not erythema, avoided in pregnancy.
How should scalp psoriasis be treated?
Use of topical corticosteroids once daily for 4 weeks
What are the secondary care management options for psoriasis?
Phototherapy - Narrow band UVB light.
Systemic therapy: Oral metotrexate, systemic retinoids, biological agents (infliximab, etanercept, adalimumab)
Coal tar
What drugs are known to exacerbate psoriasis?
Beta-blockers Lithium NSAIDs ACEi TNF-alpha inhibitors Anti-malarials
