Psoriasis Flashcards
What is psoriasis?
Chronic, genetically, immune-mediated inflammatory skin condition
What kind of lesions is psoriasis usually characterised by?
Usually characterised by typically well-defined, scaly plaques
What is the prevalence of psoriasis?
3% of UK population
How does the prevalence of psoriasis compare between males and females?
M:F is equal
In what age group is the peak incidence of psoriasis?
20s and 50s
Is there any genetic factor to psoriasis?
>1/3 have family history
As well as the physical implications of psoriasis, what else must be considered?
Psychological implications
What other diseases is psoriasis linked to?
Is a systemic disease, linked to metabolic syndrome and cardiovascular disease
Describe the appearance of psorasis lesions?
Red scaly plaques, often symmetrical distribution
What causes psoriasis?
Overactivity of the immune system, excessive production of TH1 cytokines including TNF-alpha:
- Vascular proliferation (erythema), increased cell turnover (plaques and scaling)
Excessive production of what causes psoriasis?
TH1 cytokines including TNF-alpha
What is the aetiology of psoriasis?
- Genetics
- Environment
- Infection
- Strep, candida
- Drugs
- Lithium, beta blockers, NSAIDs, steroid withdrawal
- Trauma
- Sunlight
What infections can cause psoriasis?
Strep
Candida
What drugs can cause psoriasis?
Lithium
Beta blockers
NSAIDs
Steroid withdrawal
Explain the pathogenesis of psoriasis?
Epidermal infiltration by activated T cells:
- Increased epidermal cell proliferation and turnover
- Cell cycle reduced from 28 days to 3-5 days
- Capillary angiogenesis
- Excessive production of TH1 cytokines, especially TNF-alpha, which is linked to flares
Often family history, so genetic link
What are some precipitants to psoriasis?
- Trauma
- Infection
- Drugs
- Sunlight
- Stress
- Smoking
- Alcohol
- HIV
What is A?
Epidermis
What is B?
Dermis
What is this histology of?
Skin
Explain the histology of psoriasis?
- Hyperkeratosis (thickening of stratum corneum) with parakeratosis (keratinocytes with nuclei in statum corneum)
- Neutrophils in stratum corneum (munro’s microabscesses)
- Hypogranulosis, no granular layer (needed for barrier function)
- Psoriasiform hyperplasia: acanthosis (thickening of squamous cell layer) with elongated rete ridges
- Dilated dermal capillaries
- Perivascular lymphohistiocystic infiltrate, T cell infiltration
What is hyperkeratosis?
Thickening of stratum corneum
What is parakeratosis?
Keratinocytes with nuclei in stratum corneum
What is Munro’s microabscesses?
Neutrophils in stratum corneum
What layer of the skin is needed for barrier function?
Granular layer
What is acanthosis?
Thickening of squamous cell layer
What are some different subtypes of psoriasis?
- Chronic plaque psoriasis
- Accounts for 90% of psoriasis cases
- Commonly managed with topical treatments in primary care
- Guttate psoriasis
- Commonly post-viral
- Usually self-limiting
- Responds well to phototherapy
- Palm-plantar psoriasis
- Have greatest impact on quality of life
- Scalp psoriasis
- Differential diagnosis of seborhoeic dermatitis
- Nail psoriasis
- Pathognomonic features include pitting and onycholysis
- Flexural/inverse psoriasis
- Lack of scale
- Pustular psoriasis
- Erythrodermic psoriasis
- “Red man” syndrome
- >90% of body surface involved
- Needs in-patient treatment
What is the most common subtype of psoriasis?
Chronic plaque psoriasis (accounts for 90% of cases_
How is chronic plaque psoriasis commonly managed?
With topical steroids in primary care
When does guttate psoriasis commonly occur?
Post-viral
What treatment does guttate psorasis respond well to?
Phototherapy
What kind of psoriasis has the greatest impact on quality of life?
Palm-plantar psoriasis
What is a differential diagnosis for scalp psoriasis?
Seborrhoeic dermatitis
What is erythrodermic psorasis also known as?
“Red man” syndrome
How much of the body is involved in erythrodermic psorasis?
>90% of body surface
How is psorasis diagnosed?
Can be clinical based on typical presentation or skin biopsy if atypical
What are some differential diagnosis for psoriasis?
- Seborrhoeic dermatitis
- Especially scalp, face
- Lichen planus
- Check forearm, oral mucosa
- Mycosis fungoides
- Older patient, sudden onset of plaques or treatment resistant plaques
What is the initial treatment for psoriasis?
Emollients:
- Creams vs ointments
Vitamin D3 analogues with or without topical steroids
Tar creams
Topical steroids:
- Fleuxural/genital area
Salicyclic acid (keratolytic)
Dithranol
Anthralin
What are emollients?
Cosmetic preparations used for protecting, moisturizing, and lubricating the skin
What is the treatment for psoriasis if initial treatment fails?
- UVB phototherapy
- Acitretin
- Teratogenic, impairment of LFTs/lipids
- Methotrexate
- Cyclosporin
- Risk of renal impairment/cancer
- Inpatinet tar
- Biologics
- Qualifying criteria, costly
- Anti-TNF (etanercept, infliximab, adalimbumab)
- IL-12, 23 inhibitor (ustekinumab)
- IL 17 inhibitor (ixekizumab, secukinumab)
- Qualifying criteria, costly
What are some biologics for the treatment of psoriasis if initial treatment fails?
- Anti-TNF (etanercept, infliximab, adalimbumab)
- IL-12, 23 inhibitor (ustekinumab)
- IL 17 inhibitor (ixekizumab, secukinumab)
What is a possible future medicine for psoriasis?
Future medicine is kinase inhibitors:
- Ethical/cost dilemmas
- Examples are adalimumab and methotrexate
What is the treatment of erythrodermic psoriasis?
- Admit
- Fluid balance
- Bloods/IV access
- Thick greasy ointment emollients
How is psoriasis monitred?
- Psoriasis Area Severity Index (PASI)
- Body area, redness, thickness, scaliness)
- Dermatology Life Quality Index (DLQI)
- Bloods etc if on systemic treatment
What does PASI stand for?
Psoriasis area severity index
What does PASI consider?
Body area, redness, thickness, scaliness
What does DLQI stand for?
Dermatology life quality index
What is the prognosis of psoriasis?
Exacerbations and remissions occur, can be difficult to treat
May progress to arthritis in 5-10%
Die earlier than controls on average
Associated with other co-morbidities:
- Cardiovascular disease, smoking, alcohol, metabolic syndrome, lymphoma, depression, suicide
What other co-morbidities is psoriasis associated with?
- Cardiovascular disease, smoking, alcohol, metabolic syndrome, lymphoma, depression, suicide
How is psorasis usually managed?
Usually managed in primary care with topical treatment and addressing risk factors:
- Smoking, alcohol, stress, drugs
What are some systemic treatments for psoriasis?
- Phototherapy, oral (retinoids, immunosuppresants), biologics
