Psoriasis Flashcards
What is the genetic factor linked to psoriasis?
HLA - Cw6
What are the pathological features in psoriasis?
Increases turnover of keratinocytes in epidermis
Thickened, parakeratotic (no nuclei) stratum corneum
Munro micro abscesses
Absence of granular layer
Expanded stratum spinosum
Large capillary vessels in dermis
Give some examples of precipitating factors for a flare up of psoriasis?
Emotional stress Infection e.g. strep throat --> guttate psoriasis Drugs Alcohol, smoking Trauma --> Koebner phenomenon HIV/AIDS UV radiation (10% worsen, 90% improve)
Which drugs might trigger psoriasis?
Beta blockers
Lithium
Antimalarials
Withdrawal of steroids
Describe the morphology and distribution of chronic plaque psoriasis?
Erythematous, scaly, raised plaques
On extensor aspects of knees, elbows, sacrum and scalp
Often symmetrical
What is the Auspitz sign seen in psoriasis?
removing scale reveals pin-point bleeding
What is the Koebner phenomenon?
Development of psoriasis as a site of trauma (2-6 weeks post trauma)
What is the treatment for scalp psoriasis?
Olive oil (softens plaques) Tar shampoo Tar/salicylic acid ointment
How does guttate psoriasis present?
guttate = raindrop appearance
–> multiple small psoriatic lesions on trunk
7-10 days post strep throat
What is flexural psoriasis?
Shiny red well-demarcated plaques in groin, axilla or inframammary (under boobs)
Scale not prominent as moist areas
Can be confused with fungal infection or intertrigo
What is the treatment for flexural psoriasis?
Mild TCS/antifungal preparation
e.g. Trimovate cream or Canesten HC cream
What is palmoplantar psoriasis?
Very painful/disabling psoriasis on palms and soles –> fissures
Very thick hyperkeratosis
What is palmoplantar pustulosis?
Not psoriasis, related disorder
Sterile yellow pustules fading to brown macules on palms/soles –> scaling
Strong association with smoking
What is erythrodermic psoriasis?
Erythroderma = > 90% of skin surface red
Uncommon complication, usually in patients with known/deteriorating psoriasis
What are some causes of erythrodermic psoriasis?
Withdrawal of potent steroids
Drug reactions
UV burns
What are the complications of erythrodermic psoriasis?
Hypothermia Cardiogenic shock Dehydration Anaemia Hypoalbuminaemia
What is the treatment for erythrodermic psoriasis?
Fluids
Emollients
Immunosuppressants
What is generalised pustular psoriasis and what are the features?
Sterile pustules within areas of psoriasis
Painful, fever, malaise
Hypoalbuminaemia, hypocalcaemia, leukocytosis
What are some causes of generalised pustular psoriasis?
Withdrawal of steroids
Infection
Pregnancy
Hypocalcaemia
What is the management for generalised pustular psoriasis?
Same as erythrodermic psoriasis
What are some of the nail changes seen in psoriasis?
Nail pitting Onycholysis Oil drop lesions (orange/brown area) Subungual hyperkeratosis Nail deformity
What is onycholysis?
Separation of nail from bed - white at tip
Which conditions are associated with severe psoriasis?
Higher incidence of obesity, DM, metabolic syndrome, CVD and stroke
What are the 3 steps in treatment of psoriasis?
- topical agents
- phototherapy
- oral treatments
Which topical therapies are used in psoriasis?
Regular emollients Coal tar (effective but messy) Dithranol (burns normal skin and stains clothes) Vitamin D analogues Salicylic acid (removes hyperkeratosis) TCS
Which topical therapy is first line for mild psoriasis and give an example?
Vitamin D analogues e.g. Calcipotriol (dovonex)
How/when should TCSs be used in psoriasis?
Mild TCS can be used, often in combination with dovonex e.g. Dovobet
Avoid potent TCS –> risk of rebound flare (erythroderma, pustular psoriasis)
Also remember risk of flare if taking oral steroids for another condition
What are the options for phototherapy in psoriasis?
UVB 3x per week for 6-8 weeks
PUVA (psoralen + UVA)
What are the acute side effects of phototherapy?
Erythema/blistering (sunburn)
Photoconjunctivitis
Exacerbation of herpes simplex
What are the chronic effects of phototherapy?
Photoageing
Photocarcinogenesis
What are the systemic treatments available for severe psoriasis?
Methotrexate (good if psoriatic arthritis)
Ciclosporin
Retinoids
Biologics
