Psoriasis Flashcards
Which infectious pathogens can trigger psoriasis?
- Beta-haemolytic streptococci
- Staphylococcal infections
- HIV
Which drugs can trigger psoriasis?
- Beta-blockers
- Chloroquine
- Lithium
- Interferon
- ACE-Is
Which HLA subtypes is psoriasis correlated with?
- HLA-Cw6
- HLA-B17
- HLA-B57
Describe the typical appearance of psoriatic lesions.
- Few lesions appear which usually become confluent
- Well-demarcated
- Erythematous
- Silvery-white scaling plaques
- Pruritic
- Demonstrate Auspitz sign
- Demonstrate Koebner phenomenon
What is the Auspitz sign?
Small pin-point bleeding where scales have been scraped off
What is the Koebner phenomenon?
When physical stimuli or skin injury leads to development of skin lesion on previously healthy skin
Describe the typical distribution of psoriasis.
- Scalp
- Back
- Elbows (extensor surface)
- Knees (extensor surface)
What nail changes are typically seen with psoriasis?
- Nail pitting
- Brittle nails
- Onycholysis
- Oil drop sign/Salmon spot: well-circumscribed, yellow-reddish discolouration of the nail
What are the clinical features of psoriatic arthritis?
- Oligoarthritis (70% of cases)
- Spinal involvement (40%) of cases
- Onycholysis and nail pitting
- Enthesitis
- Tenosynovitis
- Dactylitis
- Arthritis mutilans: destruction of IP joints (esp DIP) and resporation of phalanges
What changes are usually seen on an x-ray of a hand in psoriatic arthritis?
- Joint destruction
- Pencil-in-cup deformity (DIPs)
What changes are usually seen on an x-ray of a spine in psoriatic arthritis?
- Joint destruction
- Syndesmophytes + asymmetric paravertebral ossification
What is the management of psoriatic arthritis?
- NSAIDs
- Methotrexate/sulfasalazine/ DMARDS (similar to RA)
- Ustekinumab/Secukinumab
What are the different cutaneous subtypes of psoriasis, and which is the most common?
- Chronic plaque psoriasis –> most common
- Flexural psoriasis
- Guttate psoriasis
- Pustular psoriasis
What is guttate psoriasis usually precipitated by?
Streptococcal infection (2-4 weeks prior to lesions appearing)
- more common in children and adolescents
Describe the appearance of guttate psoriasis.
- ‘Tear drop’, scaly papules
- Usually on trunk and arms
Which HLA subtype is closely correlated to pustular psoriasis?
HLA-B27
Why is it important to promptly diagnose and treat pustular psoriasis?
*Occurs on palms and soles
Can lead to erythroderma, which may lead to severe illness with fever and dehydration, and can be fatal
What is 1st-line treatment for chronic plaques psoriasis?
- Always - regular emollients
- Potent corticosteroid (Eumovate/Betnovate) OD + vitamin D analogue OD
What is 2nd-line treatment for chronic plaques psoriasis?
If no improvement after 8 weeks then apply vitamin D analogues BD
What is 3rd-line treatment for chronic plaques psoriasis?
- If no improvement after 8-12 weeks
- Potent corticosteroid (Betnovate/Dermovate) applied BD for up to 4 weeks, OR
- Coal tar preparation applied OD/BD
- Short-acting dithranol can also be used
What management for psoriasis can be provided by secondary care?
- Phototherapy –> narrowband UVB light 3x/week
- Photochemotherapy (psoralen + UVA/PUVA)
What are the important adverse effects of phototherapy?
- Skin ageing
- SCC
What systemic therapies can be provided if topical/photodynamic therapy fails?
- 1st-line: Oral methotrexate
- Ciclosporin
- Systemic retinoids
- Biological agents: infliximab, etanercept, adalimumab
What is the management for scalp psoriasis?
- Potent topical steroids (betnovate/dermovate) OD for 4 weeks
- No improvement after 4 weeks –> use different corticosteroid formulation and/or topical agent to remove adherent scale before steroid application
What is the management of face/flexural/genital psoriasis?
Mild (hydrocortisone) or moderate (eumovate) corticosteroid applied OD/BD for a max of 2 weeks
What are the potential side effects of topical steroids? What is done to prevent/minimise this in management of psoriasis?
Side effects:
- Skin atrophy
- Striae
- Rebound symptoms
Prevention:
- Scalp/face/flexures: prone to steroid atrophy therefore do not use for >1-2 weeks per month
- Aim for 4 weeks breaks before starting another course of topical steroids
- Use potent steroids (betnovate) for no more than 8 weeks at a time
- Use very potent steroids (dermovate) for no more than 4 weeks at a time
Which conditions is someone with psoriasis at increased risk of?
- Metabolic syndrome
- CV disease (HTN, CHD, MI, Stroke)
- CKD
