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12/13 psoriasis
Derm
30
Medical
Graduate
12/14/2011

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Cards

Term
epidemiology of psoriasis
-age of onset
-peaks of occurence
Definition
-average onset 33 years
-two peaks: 22.5 years, 55 years
-earlier onset (<15 years) correlated with worse disease and family history
Term
comorbidities with psoriasis
Definition
systemic diorders
-Chron's
-metabolic syndrome
-depression
-cancer (skin, lymphoma)

*moderate and severe psoriasis patients have increased risk of CV disease*
-may be due to circulating proinflammatory factors that may lead to damage of endothelial blood vessels
Term
subtypes/variants of psoriasis
Definition
chronic plaque
inverse
guttate (eruptive)
erythrodermic
pustular

variants may coexist in one person
nails and joints can often be involved
Term
chronic plaque psoriasis

clinical features
Definition
most common variant

-itchy
-thick, raised plaque
-sharp demarcation
-erythematous under scale
-silvery scale
-Auspitz sign
Term
Auspitz sign
Definition
pinpoint hemorrhage seen when scale removed because there are many elongated and dilated blood vessels in the upper dermis
Term
chronic plaque psoriasis

common locations
Definition
SCALP
ELBOWS
KNEES

also: gluteal cleft, hands & feet, retroauricular, periumbilical

often shows SYMMETRIC involvement
Term
Koebner phenomenon
Definition
~25% of patients will develop psoriasis in areas of prior skin injury (trauma, sunburn, drug eruptions, viral exanthems)
Term
inverse psoriasis

clinical features
Definition
sharply demarcated, raised, glossy erythema

absent scale because located in skin folds (moisture)
Term
inverse psoriasis

common locations
Definition
skin folds:
-axillae
-genital, gluteal
-inframammary
Term
eruptive/guttate psoriasis

clinical features
Definition
multiple papules <1cm

classically follows infection with strep pharyngitis and seen in younger patients

(much better prognosis)
Term
eruptive/guttate psoriasis

common locations
Definition
upper trunk and proximal extremities
Term
erythrodermic psoriasis

clinical features
Definition
generalized disease - total body involvement: eryhtema, scaling

hospitalization; fever/chills, fluid imbalance, electrolyte imbalance
Term
pustular psoriasis

clinical features
Definition
generalized or localize forms

sterile pustules on red skin (no silver plaques)

systemic: fever, weight loss, increased WBC, hypocalcemia, elevated ESR

reason to hospitalize
Term
triggers of pustular psoriasis
Definition
pregnancy

systemic corticosteroid withdrawal

infection
Term
nail involvement
Definition
present in up to 80% of patients
fingers > toes

pitting: most common finding
oil spots: psoriasis under nail plate
onycholysis: separation of plate/bed
anonychia: complete nail loss, pustular involvement
Term
psoriatic arthritis
Definition
seronegative arthritis in up to 30% of patients

usually *asymmetric oligoarthritis*
Term
histology
Definition
thick epidermis with elongated rete ridges from increased epidermal proliferation

scale from abnormal keratinocyte differentiation with retention of many dead keratinocytes

redness from elongated and dilated blood vessels in upper dermis

many inflammatory cells present: T-cells and dendritic cells, usually found around blood vessels
Term
factors contributing to the pathogenesis of psoriasis
Definition
-multi factorial disease
-maybe autoimmune/autoinflammatory
-genetics
-immune factors
-environmental factors
Term
genetic contributions to psoriasis
Definition
-inheritance of many genes PLUS environmental triggers is key
-positive family history in 35-90%
-MZ>DZ risk
Term
specific gene involvement
Definition
linkage gene studies have identified:

*PSORS1* key chromosomal locus

*HLA-Cw6* gene at PSORS1 locus
associated with 13x increased risk and with early onset and guttate/eruptive types
Term
immune factors
Definition
numerous elements of the immune system are involved

activated Tcells

cytokines
Term
evidence for T cell involvement in psoriasis
Definition
psoriasis is T-cell mediated

numerous T cells can be seen in active lesions

targeting T cells (cyclosporine, UV light) improves psoriasis
Term
role of Th-17
Definition
T cells in psoriasis are polarized to the Th-17 phenotype

Th-17 cells produce cytokines that drive the development of psoriasis plaques:
IL-17 --> T cell influx
IL-22 --> acanthosis
Term
polarization of Tcells to Th-17
Definition
naive T cells differentiate to Th-17 in the presence of IL-6, TGF-beta, and IL-23
Term
paradigm of immune involvement in psoriasis
Definition
some effect of Th-1 activity, but Th-17 is the major player
Term
role of dendritic cells
Definition
Th-17 cells are stimulated by IL-23 derived from dendritic cells
Term
key cytokines in psoriasis
Definition
IL-23 (from dendritic cells)
IL-17, IL-23 (from Th-17 cells)
INF-gamma (from IL-1)
TNF-alpha
Term
targeting TNF-alpha in psoriasis treatment
Definition
therapies that bind to an neutralize the pro-inflammatory effects of TNF-a

Etanercept
Infliximab
Adalimumab
Term
targeting IL-23 in psoriasis
Definition
IL-23 stimulates Th-17 cells

*ustekinumab* specifically targets IL-23
-fully human antibody that neutralizes IL-23, dampens activity of Th-17 cells
Term
non-targeted psoriasis therapies
Definition
topicals used when <10% skin surface (topical steroids, Vit D analogues)

10-20% surface involvements:
UV phototherapy
retinoids
methotrexate
cyclosporine
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