Psoriasis Flashcards
What causes the development of psoriasis?
Polygenic predisposition and environmental triggers
Family history is very common
What HLA is associated with psoriasis?
HLA-Cw6 (Chromosome 6)
What are examples of environmental triggers?
Infection
Drugs
Trauma
Sunlight
What is the involvement of the immune system in psoriasis?
Stressed keratinocytes - activation of dermal dendritic cells
These dermal dendritic cells travel to the lymph nodes and present antigen to niave T cells
T cells differentiate into Th 1, 17 and 22
Leads to psoriatic dermis and plaque formation
Keratinocyte proliferation because interleukins and TNF alpha amplify inflammatory cascade
VEGF causes angiogenesis
Neutrophils in acute, active, pustular phase
The cell cycle is reduced from 28 days to 3-5 days
What is the histology of psoriasis?
- Hyperkeratosis (thickening of stratum corneum)
- Neutrophils in stratum corneum (munro’s microabcesses)
- Psoriasiform hyperplasia: Acanthosis (thickening of squamous cell layer) with elongated rete ridges
- Dilated dermal capillaries
- T cell infiltration
Describe the skin in psoriasis
–Sharply demarcated, erythematous, papulosquamous plaques
–Numerous small, widely disseminated papules & plaques
Pustules
Erythroderma
Describe the nails in psoriasis
–Onycholysis, pitting, oil spots
Onchylosis: is a common medical condition characterized by the painless detachment of the nail from the nail bed, usually starting at the tip and/or sides.
What is chronic plaque psoriasis?
Chronic
Salmon coloured plaques
Found on extensor surfaces and is extensive
What is Guttate psoriasis?
Acute onset generalised rash
Papules
Affects children and adolescents
Papules worse on trunk and proximal extremities
Check ASO titre
Can be triggered by viral or bacterial infections
It may resolve or it may even trigger chronic psoriasis
What form of psoriasis is associated with skin on the palms and soles appears thick, scaly and red with yellowish brown lesions at the edges?
Palmo-plantar Psoriasis
What type of psoriasis is associated with severe dandruff - pink hyperkeratotic plaques at her scalp
Scalp psoriasis
What type of psoriasis causes pitting in the nails?
Nail psoriasis
What type of psoriasis is likely to occur bilaterally in the axilla?
With NO scale
Flexural / inverse psoriasis
What can trigger or even superinfect flexural psoriasis?
Can be triggered or superinfected by localised dermatophyte, candidal or bacterial infection – these are also differential diagnoses
What type of psoriasis has generalised red tender patches with multiple yellow pustules?
Pustular psoriasis
Pustules are sterile - sometimes features systemic symptoms
What causes pustular psoriasis?
Pregnancy
Rapid taper / stoppping steroids
Hypocalcaemia
Infection
Erythrodemic psoriasis is often a complication of psoriasis - what is the differential?
Red man syndrome - drug reaction to vancomycin
What is the diagnosis of psoriasis?
Skin biopsy
What are the differential diagnosis’ for psoriasis?
- Seborrhoeic dermatitis
- Lichen planus
- Mycosis fungoides
What is the treatment of psoriasis?
Most treated in primary care - less than 30 % are referred to dermatology
Emollients (creams vs ointments)
Soap substitutes
Vitamin D3 anologues - these inhibit epidermal proliferation
Coal tar creams
Topical steroid
Salycilic acid (keratolytic) - this is a descaling agent
What are the available treatments in dermatology?
- Crude Coal Tar (inpatient or day treatment)
- Dithranol: since 1916. Can burn.
- UVB Phototherapy (not the same as sunbed)
–Guttate
What systemic disease is associated with psoriasis?
–5-30% develop psoriatic arthritis
–Psychosocial implications
–Metabolic syndrome – more susceptible to having cardiovscular complications
What are the systemic treatments of psoriasis?
•Retinoid - Acitretin
–Teratogenic, LFTs, lipids
•Immunosuppression
–Methotrexate
- Can treat PsArthritis
- Max improvement 8-12 weeks
–Ciclosporin
•Renal, cancer risk
•Biologic Therapies
–Qualifying criteria, cost
–Anti-TNF: Etanercept, infliximab, adalimumab
–IL-12,23: Ustekinumab
–Patient can form antibodies to biologic
Future treatments
- Targeted biologics
- IL-17,20,22
- Kinase inhibitors
- Ethical / cost dilemmas
–Adalimumab ~£9000 per year (£225000 for 25 years)
–Methotrexate ~£12.50 per year
What is the treatment of Erythrodermic Psoriasis?
- Admit
- FLUID BALANCE
- Bloods / IV access
- Thick greasy ointment emollients
- ?Systemic or biologic treatment
- ?Trigger
What can be used to monitor the progress of psoriasis?
•Psoriasis Area Severity Index (PASI)
–Surface area, plaque colour, thickness, scale
•Dermatology Life Quality Index (DLQI)
–QOL in last 1 week
