Lecture 24 - psoriasis Flashcards
what is psoriasis
Psoriasis is a Chronic inflammatory skin condition characterised by clearly defined, red and scaly plaques (thickened skin). it affects 2% of the population. Male/female are equally affected.
Genetic factors are important, especially in the younger age group - a family history is present in 40-50% of cases and up to 75% if onset is before age 20
Lifetime risk - 4% if no family history, 28% if one parent affected, 65% if both parents affected
Psoriasis may develop at any age although it most frequently presents in young adults as well as in the sixth and seventh decades
what are triggers of psoriasis?
Stress- is strongly associated with psoriasis
Alcohol- heavy drinking is more common in patients with psoriasis. Excessive alcohol may have a direct effect on psoriasis, in addition, reduced compliancewith treatment is likely to exacerbate symptoms
Smoking- is a risk for both palmoplantar pustulosis and chronic plaque psoriasis
Trauma - psoriasis can occur at the site of skin injury (Köebner phenomenon)
Infection - streptococcal infection, especially of the throat is well known to provoke guttate psoriasis. Continuing subclinical infection may also play a role in refractory chronic plaque psoriasis. HIVexacerbates psoriasis
Drugs- a wide range of drug are said to affect psoriasis. The most notable associations include lithium and certain anti-malarials such as hydroxychloroquine
Pregnancy - if psoriasis alters it is more likely to improve in pregnancy but get worse postpartum
Sunlight - although sunlight is generally beneficial, a small minority have symptoms provoked by strong sunlight
what are other ideas conditions or associated morbidities with psoriasis ?
Psoriatic arthritis (PsA)- up to 30% of patients
Cardiovascular disease
Mental health- anxiety and depression
Inflammatory bowel disease
Demyelinating disorders
Heart failure
what is the pathophysiology behind psoriasis ?
Abnormally large numbers of T-cells trigger the release of cytokines in the skin causing the inflammation, redness, itching and flaky skin patches characteristic of psoriasis
what are treatment options fro psoriasis ?
Topical
UVB
Systemic
Biologic
what are topical treatment options for psoriasis ?
Emollients
Corticosteroids (+/- antibacterial/antifungal)
Coal tar
Vitamin D analogues (calcipotriol)
Salicylic acid
Dithranol
Calcineurin inhibitors (tacrolimus/pimecrolimus)
what are systemic medications for moderate to severe psoriasis ?
Methotrexate
Ciclosporin
Acitretin
Fumaric acid esters
Apremilast
what is the methotrexate dose for psoriasis ?
7.5mg-25mg weekly (tablets or sc injection)
Monitor U&Es, LFTs, FBC 2 weekly until dose stable for 6 weeks then when on stable dose – monthly for 3 months then thereafter at least every 12 weeks.
For dose adjustments – 2 weekly until dose stable for 6 weeks then revert to previous schedule
there are risk of immunosuppression that can cause neutropenia
what is the cyclosporin dose for psoriasis ?
1.25mg/kg BD- 2.5mg/kg BD
Effective and rapid clearance
Monitoring- U&Es, LFTs, FBC baseline then 2 weekly until on stable dose for 8 weeks then monthly
BP- every visit
Fasting lipids- baseline, after 1 month then every 3 months
Max 2 years of use
Risks- renal toxicity, immunosuppressant,
when are biologics used
Biologic agents are approved for use in moderate-to-severe psoriasis in patients who:
- Have failed to respond to either methotrexate (MTX), ciclosporin or phototherapy.
- Patients have contra-indications or have developed side effects to the above.
- Patients have responded to ciclosporin but have exceeded the licensed duration of use (2 years).
- Patient has co-morbid PsA and has failed MTX/MTX contraindicated.
Moderate/severe psoriasis classed as PASI>10, DLQI>10
what is PASI/DLQI
PASI- psoriasis assessment severity index
Measurement performed by the reviewing clinician which reviews how extensive psoriasis is on that day
4 criteria- thickness, scale, erythema and %BSA covered
DLQI- dermatology quality of life index
- Patient reported score assessing how skin disease if affecting their every day life
What anti-TNF BIOLOGICS USED IN PSORIASIS
Adalimumab (fortnightly), certolizumab (fortnightly), infliximab (8 weekly), etanercept (weekly)
Adalimumab 1st biologic of choice in NHS GGC
Certolizumab- licenced in pregnancy/breastfeeding
Infliximab- IV infusion, weight based dosing
Contraindications: heart failure (NYHA III/IV), hx demyelinating disorder
Pros- experience/data, useful for co-morbid PsA, IBD, relatively quick onset, TDM, scope for dose escalation, can use in pregnancy until 2nd trimester, safe in breastfeeding, cost
Cons: immunogenic, less targeted than newer agents
what are IL-17 inhibitors?
Secukinumab (4 weekly), ixekizumab (4 weekly), brodalumab (2 weekly)
Use with caution in patients with PMH IBD/recurrent thrush/hx of depression
Pros: fast response (within 4 weeks), secukinumab and ixekizumab licensed for PsA
Cons: cost, side effects, no options for weight based dosing
what are IL-23 inhibitors?
Guselkumab (8 weekly), risankizumab (12 weekly), tildrakizumab (12 weekly)
Pros: long half life - less frequent dosing, less immunosupression, less side effects, some options for weight based dosing (tildrakizumab)
Cons: cost, longer time to response, new agents so limited long term data, pre-filled syringes
