Psoriasis Flashcards
What are the features of psoriatic nails?
- Periungal erythema
- Pitting
- Oil spots
- Subungal hyperkeratosis
- Onycholysis
What are differentials for a rash?
- Psoriasis
- Lichen planus
- Atopic eczema
- Sebhorroeic dermatitis
- Pityriasis versicolor
What are features of a rash to look for?
- Appearance of individual lesions
- Pattern of distribution (flexor, extensor, photoexposed)
- Involvement of other areas (nails, hair)
What is the presentation of chronic plaque psoriasis?
- Commonest clinical appearance (40%)
- Typical distribution pattern: ears, umbilicus, genitalia, nails, knees, toenails, scalp, elbows and natal cleft (above bum crack)
What is the presentation of guttate psoriasis?
- Describes small pink plaques of psoriasis seen on the trunk, often after a streptococcal sore throat
- Name comes from Latin ‘gutta’ meaning drops
- More common in younger individuals
- 1/3 of these patients > chronic plaque psoriasis
- Covering 50% of the body surface area would require referral to the dermatologist
What is the presentation of flexural psoriasis?
- Psoriasis affecting the genitalia or axillae
- These are sites of friction and do not show the typical silvery scale
- Usually the appearance is red (erythematous) and slightly shiny, but there will still be a clearly defined edge between normal and affected skin
- Patients are particularly distressed when there is involvement of the genitalia as this can cause difficulties with maintaining intimate relationships
What is the presentation of erythrodermic psoriasis?
- Psoriasis can flare-up and become very inflamed. When it covers over 90% of the body surface it is described as erythroderma (potentially life-threatening).
- The skin is red, feels hot and even painful
- There may be no clearly defined plaques
- Patients can feel unwell and become hypotensive, they should be admitted to hospital for treatment
What is the presentation of generalised pustular psoriasis?
- Rarely a patient’s psoriasis can flare, become red, hot, painful and develop pustules within the plaques
- Redness needs to be looked for carefully in patients with pigmented skin but can seen more easily when compared with normal skin
- This type of psoriais, though rarely seen, is an emergency requiring hospital admission
- The triggers is withdrawal of inappropriate use of super potent topical (used for several months over a large body surface area) or systemic corticosteroids therapy
What is psoriatic arthropathy?
- Between 5-20% of patients with psoriasis have arthropathy affecting their joints
- Arthropathy can precede (50%) or post-date (15%) the development of skin lesions
- The patterns of arthropathy fall into 5 subtypes: distal interphalangeal alone, symmetrical polyarthritis, asymmetrical oligoarthritis, arthritis mutilans, spondyloarthropathy
What are triggers for psoriasis?
- If presenting <40yrs (75%) genetic linkage with HLA-CW6 (Psors 1 gene on chromosome 6)
- If presenting 55-65 yrs (25%) - no genetic link
- Certain medications are known to trigger psoriasis - antimalarials, NSAIDs, beta blockers (non-selective), lithium and terbinafine (oral antifungal)
- Suddenly stopping steroid tablets can trigger or worsen psoriasis
- Alcohol
- Psychological stress
- Infections
- Damage to the skin
- Intense sunlight
What is used in the management of psoriasis?
- An emollient to use at least every 12hrs all over the body
- Soap substitute for the bath or shower
- Topical treatment with a vitamin D analogue for the trunk and limbs
- A mild topical steroid ointment for the face and flexures
What is the epidemiology of psoriasis?
- Most frequently presents in mid 20s but can affect patients at any age
- About 75% cases are before age 40
- Affects men and women equally
What is the pathology of psoriasis?
Skin affected by psoriasis is red and scaly. The outer layer of skin (epidermis) contains skin cells which are continuously being replaced - this normally takes between 3-4 weeks. In psoriasis, skin cells divide more quickly so that cells are both formed and shed in as little as 3-4 days. The inflammatory response is mediated via Th1 cells leading to an inflammatory cascade involving TNF alpha.
How can lifestyle factors affect psoriasis?
Obesity and smoking are associated with poor response to psoriasis treatments so exercise and being healthy weight can help.
Describe the PASI Scoring System for psoriasis
Psoriasis Area Severity Index - objectively measures disease severity completed by clinician - 0 = no disease, 72 = maximum disease. Useful for grading severity of patient’s disease at a particular point.
- Mild: 0 PASI
PASI can also objectively monitor patient’s response to treatment e.g. PASI50 (meaning 50% improvement following commencement of treatment compared to baseline) or PASI75 (75% improvement)
Describe the DLQI scoring system for psoriasis
Dermatology of Life Index = subjective assessment on impact of disease on life, completed by the patient - calculated by summing the score of each question resulting in a score between 0-30. The higher the score the more QoL is impaired:
- 0-1: no effect at all on patient’s life
- 2-5: small effect on patient’s life
- 6-10: moderate effect
- 11-20: very large effect
- 21-30: extremely large effect
What is used to screen for psoriatic arthritis?
Up to 30% of patients with psoriasis also suffer from psoriatic arthritis. The PEST (Psoriasis Epidemiology Screening Tool) score is used to screen for psoriatic arthritis. A total score of 3 or more out of 5 is positive and indicates a referral to rheumatology should be considered. In cases of suspected psoriatic arthritis, early referral to a rheumatologist is advocated to diagnose psoriatic arthritis to avoid permanent joint destruction.
What is the general advice given about psoriasis treatment?
- Advise patients to treat affected areas until plaques are no longer palpable, any residual colour changes will improve without further active treatment.
- Advise patients to continue with emollients, ideally review patient at 4-6 weeks or ask patient to return earlier if they clear sooner
- Ensure patient understands how to self-manage their psoriasis with an agreed treatment plan
Describe phototherapy as a treatment for psoriasis
- Narrow band UVB or PUVA - slows down excess keratinocyte growth and considered to be partially immunosuppressive. Highly effective form of treatment - given 2-3x /week for up to 10 weeks.
- Some patients get re-flares within weeks of treatment finishing
- PUVA treatment has shown to increase lifetime risk of skin cancer so patients are limited to max 100 sessions total in their lifetime
What treatments are offered if patients have failed phototherapy?
- Systemic treatments. Compared to biologics, they have various side effects and are linked to various toxicities. Most patients will require intensive monitoring (both blood and clinical evaluation) whilst commencing treatment and once established on treatment will need regular dermatological review
- Examples are ciclosporin, methotrexate, acitretin, fumaric acid, apremilast
- In situations where systemic agents don’t provide adequate response or aren’t tolerated or are contraindicated, step up treatment in the form of biological therapy should be considered.
Describe biological treatment for psoriasis
- Monoclonal antibodies which inhibit specific immunological targets which are intrinsically related to pathogenesis of psoriasis.
- The benefits include significantly improved efficacy rates and inhibition of pathways associated with extra cutaneous manifestations of psoriasis, particularly psoriatic arthritis.
- Unfortunately they are expensive so patients can only be commenced on these if they have previously failed on at least 2 systemic agents and suffer from severe psoriasis - PASI + DLQI of at least 10.
- Can elicit host immune response termed ‘anti-drug antibody’ - believed to contribute to treatment resistance, culminating in development of secondary failure
What biologics are used for psoriasis?
- TNF inhibitors e.g. etanercept, infliximab, adalimumab and certolizumab - most commonly prescribed is adalimumab as a SC injection given every 2 weeks and is associated with PASI75 in 70% of patients and PASI100 in 15-20%.
- IL 12/23 inhibitors: Ustekinumab is currently the main one used - SC injection every 12 weeks and results in PASI75 in 76% and PASI90 in 57% after 12 weeks of treatment
- IL-17 inhibitors: secukinumab, brodalimumab and ixekizumab
What biologics are given to a young person with severe psoriasis?
Adalimumab, etanercept, ustekinumab
What other conditions are patients with psoriasis known to have an increased risk of?
- MI
- T2DM
- Hyperlipidemia
- Metabolic syndrome (combination of diabetes, HTN and obesity)
