Psoriasis Flashcards
Prevalence:
-2 % worldwide
% of patients with psoriatic arthritis?
- 5-30%
Age of onset:
- bimodal distribution peaking at 20-30 years, and 50-60 years
General pathogenesis of psoriasis:
- caused by environmental triggers in genetically predisposed patients
triggers for psoriasis:
SICK LAB - stress/smoking - Infection (group A strep, URI) - hypoCalcemia - Koebnerization - Lithium - antimalarias/ACEI/alcohol - Beta blockers Others: TNF alpha inhibitors!!!, CCB’s, NSAIDs
most important psoriasis susceptibility region is ___ which is present in ____ % of patients
- PSORS1 - 50%
strongest HLA association:
- HLA cw6 (C-wia-six)
HLA cw6 is positive in ____ % of early onset psoriasis
- 90%
strongest HLA risk factor for early onset disease is_____
- HLA cw6
HLA-B27 is a/w
- sacroiliitis-associated psoriasis - PsA - pustular psoriasis
HLA cw6 is a/w which subtype of psoriasis?
- guttate
HLA- B13 and HLA-B17 a/w:
- guttate and erythrodermic psoriasis
HLA A,B,C encode _____
- MHC class 1 on nucleated cells
HLA DR, DP, DQ encode ____
- MHC class 2 on APC’s
Name the variants of psoriasis:
- guttate - palmoplantar - inverse - erythrodermic - pustular (including impetigo herpetiformis in pregnancy, and Von Zumbusch)
The two generalized pustular psoriasis are:
- impetigo herpetiformis - Von Zumbusch
Impetigo herptiformis presentation and management:
- presents in pregnant patients, begins in flexures then generalizes w/ toxicity - early delivery recommended
Von Zumbusch presentation:
- rapid and generalized, painful skin, fever, leukocytosis, hypoalbuminemia
Risk factor for Von Zumbusch :
- hypocalcemia
Palmoplantar pustulosis presents as ____ and has a ____ course.
- pustules and yellow-brown macule localized to plams/soles - chronic course
Palmoplantar pustulosis may be a/w sterile inflammatory bone lesions in _____
SAPHO syndrome
Acrodermatitis of Hallopeau presents as:
- lakes of pus on distal fingers, toes, and nail beds–> nail shedding - think of “lake hallopeua”
1 cause of pityriasis amianacea is ____
psoriasis
Nail findings in psoriasis:
- Proximal matrix= Pits - Distal matrix= leukonychia and loss of transparency - nail bed= oil spots, splinter hemorrhages, onycholysis, sublingual hyperkeratosis
Psoriatic arthritis is more likely if ____ and ____ are involved.
- nails - scalp
PsA presents as ____
- morning stiffness >30-45 mins
5 types of PsA:
- oligoarthritis with swelling and tenosynovitis of hands (60-70% of cases!!!!!!) - asymmetric DIP with nail damage - RA-like - Arthritis mutilans (rare and most severe) - Ankylosing spondylitis
most common type of PsA
oligoarthritis with swelling and tenosynovitis of hands (60-70% of cases!!!!!!)
Good way to distinguish RA from PsA
- PsA affects PIPs, DIPs, usually spares MCPs - RA affects MCPs, PIPs, spares DIPs
Common trigger for guttate psorisasis
- group A strep infection (oropharynx or perianal)
Dactylitis is ____ and seen in ____ % of patients with PsA
- swelling of fingers (sausage digit) - 15-30%
Histology of psoriasis:
- confluent PK - Munro’s micro abscesses (collections of neuts in the stratum corneum, neuts in horn) - decreased or absent granular layer - regular acanthoses with thinning over dermal papilla, which contain dilated capillaries
Munro’s microabcesses are:
- collections of neutrophils in stratum corneum (neuts in the horn)
The granular layer in psoriasis is _____
- decreased or absent
7 basic steps of psoriasis immunology in order:
- environmental triggers + genetic susceptibility 2. Keratinocyte injury and increased antigen presentation 3. Increased production of proinflammatory cytokines (IL-23, IL-12, IL-17, IFN-gamma, TNF, and IL-22) 4. Activation of T cells by myeloid dendritic cells leading to Th1 and Th17 activation and proliferation 5. epidermal acanthuses and abnormal keratinocyte proliferation 6. Increased production of beta defensins, cathelicidin LL37.
Th17 cells are stimulated by ____ . This in turn increases release of _____ and ____ which causes keratinocyte replication
- IL-12 and IL-23 - Th17 cells lead to release of IL-17 and IL-22
Th1 cells are stimulated by _____ and lead to production of ____________.
- stimulated by IL-12
Two main cytokines involved in the increase in keratinocyte replication:
- IL-17 and IL-22 (these are released by Th17 cells.
IL-12, which stimulates Th1 cells promotes CD8 T cells to secrete:
- IFN-gamma - IL-2,6,8,12
IFN-gamma activates _____ to secrete ____ and _____
- macrophages - TNF-alpha and IL-23
Th17 cells release ____, ____ and ____
- IL-17 - IL-22 - TNF-alpha
Th2 cells are stimulated by ____ and produce _____, which is decreased in psoriasis
- IL-4 - produce IL-10
IL-10 is an anti-inflammatory cytokine which inhibits _____
- Th1 cells - since there is less IL-10, there are more Th1 cells that release more pro inflammatory cytokines
Mechanism of topical corticosteroids:
- decrease pro-inflammatory cytokines like TNF-alpha and increase IL-10 (anti-inflammatory cytokine)
MOA of Calcipotriene:
- vitamin D analog that decreases KC proliferation and blocks IL-2, IL-6, and IFN-gamma
Which molecule leads to neutrophil chemotaxis and micro abscess of munro formation?
- CXCL8
Associated comorbidities of psoriasis:
- decreased risk of allergies and superinfections - increased risk of cardiovascular diseases, HLD, HTN, DM, metabolic syndrome
Micropustules of Kogoj are_____
- collection of neutrophils in stratum spinosum
Where are micro pustules of Kogoj and munro microabcesses located in skin?
- munro are neuts in the stratum corneum - Kogoj are neuts in the stratum spinosum - remember “Marilyn Monroe is always on top”
First line tx for mild-moderate psoriasis?
- topical CS
Fist line tx for moderate-severe psoriasis?
- NB-UVB (311-313nm)
How often does psoriasis spontaneously remiss?
<35% of the time, the rest tend to have chronic course
Woronoff ring is ____
- pale blanching ring around psoriatic lesion
Scraping of psoriasis scale off will lead to ____ which is called _____ sign.
- pinpoint bleeding - auspitz sign
Auspitz sign occurs due to____
- dilated capillaries and supra-papillary plate thinning
