What is psoriasis characterized by?
- thickening of the epidermis
- elongated rete ridges
- mixed cellular infiltrate
What are scales a result of?
- hyperproliferative epidermis with premature maturation of keratinocytes
- incomplete cornification with retention of nuclei in stratum corneum
What contributes to the overall thickness of lesions?
- hyperproliferation of the dermis
- inflammatory infiltrate
What does the inflammatory infiltrate consist of?
- dendritic cells (dermis)
- macrophages (dermis)
- T cells (dermis)
- neutrophils (epidermis)
- some T cells (epidermis)
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)
The risk of psoriasis is higher in what types of people?
- 1st and 2nd degree relatives
- monozygotic twins
The 9 chromosomal loci linked to psoriasis are referred to as what?
psoriasis susceptibility 1 through 9 (PSORS1 through PSORS 9)
What are the key cytokines produced by innate immune cells?
What do the key cytokines activate?
myeloid dendritic cells
What do activated dendritic cells do?
present antigens and secrete mediators (IL-12 and IL-23)
What do IL-12 and IL-23 lead to?
differentiation of type 17 and type 1 helper T cells (Th17 and Th1)
What do the mediators secreted from T cells do?
- activate keratinocytes
- induce production of antimicrobial peptides, proinflammatory cytokines, chemokines, and S100 proteins
What does IL-12 do?
promotes proliferation and differentiation of Th1 helper T cells
What do TNF-a/INFy from Th1 cells promote?
- integrin formation (ICAM)
- keratinocyte proliferation
What does IL-23 do?
promotes proliferation and differentiation of Th17 helper T cells
What do IL-17 and IL-22 promote?
hyperproliferation of keratinocytes
What is the immune response due to?
- antigen or result of trauma
- intracellular cell adhesion molecules (ICAM)
- antigen presenting cells (APCs)
Where do overactive T cells migrate from?
what cytokines are primarily involved in psoriasis?
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)
What are the contributing factors of psoriasis?
- alcohol (greater on men)
- smoking (greater on women)
- infection (Streptococcal)
- trauma (Koebner response)
What drugs aggrevate psoriasis?
- Some antimalaria drugs
What is an Auspitz sign?
small pinpoints of bleeding when scales are removed
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
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
What are characteristics of inverse psoriasis?
- skin folds
- smooth, red, without plaque
- irritated by friction, sweat retention, warmth
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)
What are the characteristics of erythrodermic psoriasis?
- 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
How is psoriasis diagnosed?
- biopsy of skin lesion
- family history