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What is psoriasis characterized by?
- thickening of the epidermis
- parakeratosis
- elongated rete ridges
- mixed cellular infiltrate
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What are scales a result of?
- hyperproliferative epidermis with premature maturation of keratinocytes
- incomplete cornification with retention of nuclei in stratum corneum
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What contributes to the overall thickness of lesions?
- hyperproliferation of the dermis
- inflammatory infiltrate
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What does the inflammatory infiltrate consist of?
- dendritic cells (dermis)
- macrophages (dermis)
- T cells (dermis)
- neutrophils (epidermis)
- some T cells (epidermis)
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What is the general treatment strategy?
- 1. moisturize
- 2. sloughing away plaques and lesions (exfoliate, keratolytics)
- 3. decrease epidermal cell proliferation (anti-mitotic)
- 4. normalize epidermal cell turnover (newer retinoids, promote differentitation - prevent mitosis)
- 5. pathogenesis-based approaches (immunosuppressant therapy)
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The risk of psoriasis is higher in what types of people?
- 1st and 2nd degree relatives
- monozygotic twins
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The 9 chromosomal loci linked to psoriasis are referred to as what?
psoriasis susceptibility 1 through 9 (PSORS1 through PSORS 9)
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What are the key cytokines produced by innate immune cells?
- TNF-a
- interferon-a
- interferon-y
- interleukin-1B
- interleukin-6
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What do the key cytokines activate?
myeloid dendritic cells
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What do activated dendritic cells do?
present antigens and secrete mediators (IL-12 and IL-23)
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What do IL-12 and IL-23 lead to?
differentiation of type 17 and type 1 helper T cells (Th17 and Th1)
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What do the mediators secreted from T cells do?
- activate keratinocytes
- induce production of antimicrobial peptides, proinflammatory cytokines, chemokines, and S100 proteins
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What does IL-12 do?
promotes proliferation and differentiation of Th1 helper T cells
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What do TNF-a/INFy from Th1 cells promote?
- chemotaxis
- integrin formation (ICAM)
- keratinocyte proliferation
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What does IL-23 do?
promotes proliferation and differentiation of Th17 helper T cells
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What do IL-17 and IL-22 promote?
hyperproliferation of keratinocytes
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What is the immune response due to?
- antigen or result of trauma
- intracellular cell adhesion molecules (ICAM)
- antigen presenting cells (APCs)
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Where do overactive T cells migrate from?
lymph nodes
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what cytokines are primarily involved in psoriasis?
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What are other cytokines involved?
- granulocyte-macrophage colony-stimulating factor
- RANTES (regulated on activation, normal T-cell expressed and secreted)
- MIG (monokine induced by INF-y -->attracts T-cells)
- IL-1,6,8,12
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What are the contributing factors of psoriasis?
- climate
- stress
- alcohol (greater on men)
- smoking (greater on women)
- infection (Streptococcal)
- trauma (Koebner response)
- Drugs
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What drugs aggrevate psoriasis?
- B-blockers
- Lithium
- ACE-inhibitors
- Interferons
- NSAIDS
- Tetracyclines
- Some antimalaria drugs
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What is an Auspitz sign?
small pinpoints of bleeding when scales are removed
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What are characteristics of vulgaris psoriasis?
- most common
- sharply demarcated, erythematous plaques possible covered with silvery/white scales
- affects elbows, knees, scalp, lower back
- skin is usually dry, may be itchy
- Auspitz sign
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What are characteristics of guttate psoriasis?
- younger age
- sudden onset
- often induced by Streptococcal infections (URI, tonsillitis, strep throat)
- small, scaly, erythematous spots
- trunk or limbs
- more widespread
- not associated with white plaque buildup
- *can for vulgaris later
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What are characteristics of inverse psoriasis?
- skin folds
- smooth, red, without plaque
- irritated by friction, sweat retention, warmth
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What are characteristics of pustular psoriasis?
- mainly adults
- may be sudden
- *may develop FROM vulgaris
- usually palms and soles (palmo-plantar pustulosis PPP)
- generalized (Von Zumbusch)
- rarely on fingertips (acropustulosis)
- white pustules with surrounding erythema (does NOT imply infection)
- rare
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What are the characteristics of erythrodermic psoriasis?
- red
- may have life threatening consequences
- affects most of body surface**
- erythema and exfoliation cause widespread itching with pain
- immediate or gradual onset
- more peeling than scales
- can lead to protein loss, fluid loss, edema, infection --> hyperthermia, tachycardia, edema, dehydration, SOB
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How is psoriasis diagnosed?
- observation
- biopsy of skin lesion
- family history
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