Psoriasis Flashcards
What is psoriasis?
Chronic inflammatory skin condition characterised by scaly erythematous plaques which typically follows a relapsing remitting course
What is the pathophysiology in psoriasis?
Genetic
Immunological - abnormal T cell activation stimulates keratinocyte proliferation
Environmental - may be worsened by skin trauma or stress, triggered e.g. by Strep infection or improved e.g by sunlight
What are triggers of psoriasis?
Stress Infection (Strep) Skin trauma Drugs - lithium , NSAIDS, beta blockers, antimalarials Withdrawal of systemic steroids Alcohol Obesity Smoking Climate
What are subtypes of psoriasis?
Chronic plaque psoriasis
Flexural psoriasis
Guttate psoriasis
Pustular psoriasis
Describe chronic plaque psoriasis
Symmetrical well-defined erythematous plaques with a silvery scale on extensor aspects of elbows, knees, scalp and sacrum
Describe flexural psoriasis
Plaques in moist flexural areas (axillae, groins, submammary areas and umbilicus)
Less scaly and often misdiagnosed as fungal infection - symmetry suggests psoriasis
Describe guttate psoriasis
Large numbers of small plaques < 1cm over the trunk and limbs are seen in the young (especially after acute streptococcal infection)
Usually lasting 3-4 months
Multiple red tear drop lesions
Describe pustular psoriasis
Yellow brown pustules within plaques affecting the pals and soles
What are nail changes in psoriasis?
PItting
Onycholysis (separation from nail bed)
Thickening
Subungual hyperkeratosis
What are complications of psoriasis?
Psoriatic arthropathy
Increased incidence of metabolic syndrome, CVS disease, VTE, psychological distress
What is management of plaque psoriasis?
Regular emollients may help reduce scale loss and reduce pruritus
1st line: Potent corticosteroid (Betnovate) applied once daily Plus vitamin D analogue (Dovonex) applied once daily (Applied separately, one in the morning and the other int he evening) for up to 4 weeks, use again if god response - do not use potent corticosteroids for > 8 weeks
2nd line:
If no improvement after 8 weeks offer a vitamin D analogue twice daily
3rd line:
If no improvement after 8-12 weeks offer either a potent corticosteroid applied twice daily for ups o 4 weeks or a coal tar preparation applied once or twice daily
Dithranol is an option
What is the risk of topical corticosteroids?
Skin atrophy
Striae
Rebound symptoms
Systemic side effects may be seen when potent corticosteroids are used on large areas
Aim for a 4 week break before starting another course of topical corticosteroids
Use potent corticosteroids for no longer than 8 weeks at a time
How do vitamin D analogues work? Example? CI?
Calcipotriol (Dovonex) Reduce cell division and differentiation May be used long-term Do not smell or stain Reduce scale and thickness of plaques but not erythema Avoid in pregnancy
What is used for scalp psoriasis?
Potent topical steroid lotion (OD for max 8 weeks) or vitamin D analogue scalp preparation
Coal tar shampoos may help
What is used for flexural psoriasis?
Mild-moderate potent topical steroid for up to 2 weeks (± antifungal/antibiotic combination)
Break for 4 weeks between courses
