Psoriasis Flashcards
What is psoriasis?
systemic, immune-mediated, inflammatory skin disease
Typically has a chronic relapsing-remitting course
May have nail + joint (psoriatic arthritis) involvement
Describe the aetiology of psoriasis
Multifactoral
Genetic predisposition
Trigger of inflammatory response (infection, irritation, drugs)
4 subtypes of psoriasis
Plaque (most common)
Pustular (2nd most common)
Guttate
Erythrodermic
List 5 conditions associated with psoriasis
Psoriatic arthropathy
Metabolic syndrome
Cardiovascular disease
VTE
Psychological distress
4 features of plaque psoriasis
Well demarcated red, scaly patches
Symmetrical distribution, extensor surfaces
Psoriatic nail changes
Koebner phenomenon
Give 5 features of psoriatic nail changes
Affect fingers + toes
Pitting
Onycholysis
Subungal hyperkeratosis
Loss of nail
4 features of guttate psoriasis
Transient (often resolves after several months)
Widespread, erythematous, fine, scaly papules (water drop appearance)
Scattered on trunk + limbs
Often triggered by Streptococcal infection
4 features of erythrodermic psoriasis
Diffuse, widespread severe psoriasis affecting >90% of body surface area
Pain, irritation, + severe itching
Malaise , fever + dehydration
Skin feels hot + uncomfortable
Describe development of erythrodermic psoriasis
Can develop gradually from chronic plaque psoriasis or appear abruptly, (even in mild psoriasis)
May be precipitated by systemic infection, irritants, phototherapy
3 features of localised pustular psoriasis
aka. Palmo-plantar pustulosis
Crops of sterile pustules on hand(s)/ feet
A/w thickened, scaly, red skin that easily develops painful fissures
3 features of generalised pustular psoriasis
RARE + SEVERE form of pustular psoriasis
Reccurent flares of widespread sterile pustules with erythematous painful skin
Involvement of mucosa + systemic features
What is koebner phenomenon?
New skin lesions of pre-existing dermatosis in areas of cutaneous injury in otherwise healthy skin
List 4 exacerbating factors of psoriasis
Trauma
Alcohol
Drugs
Withdrawal of systemic steroids
List 6 drugs that may exacerbate psoriasis
B-blockers
Lithium
Antimalarials: Chloroquine + hydroxychloroquine
NSAIDs
ACEi
Infliximab
Dx of psoriasis
Clinical
Biopsy if unsure
Which forms of psoriasis are potentially life-threatening medical emergencies?
Generalised pustular psoriasis
Erythrodermic psoriasis
Describe the step-wise management for plaque psoriasis
- Potent CS OD plus vitamin D analogue OD, applied separately (1 AM, 1 PM) for up to 4w
- If no improvement after 8w offer: vitamin D analogue BD
- If no improvement after 8-12w offer either:
a potent CS applied BD for up to 4w, or
a coal tar preparation applied OD-BD
Short-acting dithranol can also be used
Regular emollients may help reduce scale loss + reduce pruritus
Give an example of a potent corticosteroid and vitamin D analogue to use in plaque psoriasis
Hydrocortisone
Calcipotriol, calcitriol + tacalcitol
When should a patient with psoriasis seek urgent medical advice?
If they experience unexplained joint pain or swelling: may be a sign of psoriatic arthritis; requires specialist referral.
What treatment options may be offered in secondary care management of plaque psoriasis?
Phototherapy
Oral Methotrexate / Ciclosporin/ Biologics
What type of phototherapy is used in treatment of plaque psoriasis?
Narrowband ultraviolet B light
3x per week
Describe management for scalp psoriasis
Potent topical CS OD for 4w
If no improvement after 4w; either use a different formulation of the potent CS (e.g. a shampoo or mousse) +/or a topical agent to remove adherent scale (e.g. agents containing salicylic acid, emollients + oils) before applying CS
Describe management of face, flexural and genital psoriasis
Mild-mod potency CS applied OD-BD for max 2w
Why should steroids only be used on the scalp, face and flexures for limited periods?
Particularly prone to steroid atrophy
When are systemic side effects of steroids seen in psoriasis?
When potent CS are used on large areas: >10% surface area
What is the recommended duration of break between topical steroids?
4w
What is the recommended maximum duration of potent and very potent topical CS?
Potent: 8w at a time
V potent: 4w at a time
What is the MOA of vitamin D analogues?
Reducing cell division + differentiation
Leads to reduced epidermal proliferation
Give 3 benefits of using vitamin D analogues
SE’s uncommon
May be used long term (unlike CS)
Don’t smell/ stain (unlike coal tar + dithranol)
What is the MOA of Dithranol? How should it be used?
Inhibits DNA synthesis
Wash off after 30 mins
Give 2 adverse effects of dithranol
Burning
Staining
Tx for erythemodermic psoriasis
Admit: IV fluids + temperature regulation
Oral Ciclosporin
Tx for guttate psoriasis
Self limting, often resolves within 3-4 months
May consider TOP CS + VIt D analogue
If widespread: Phototherapy
Tx for generalised pustular psoriasis
Admit: IV fluids
Ciclosporin/ Methotrexate
5 patterns of psoriatic arthropathy
Asymmetrical Mono- or oligoarticular
Symmetric polyarthropathy
DIP arthritis
Arthritis mutilans
Spondylitis with sacroiliac + spinal involvement
Tx of psoriatic arthropathy
NSAIDs
DMARDs e.g. Methotrexate if progressive
What % of patients with psoriatic arthropathy have nail changes?
80-90%
