Psoriasis Flashcards
Which part of normal skin layers does psoriasis originate from?
Epidermis
How is psoriasis different from acne and dermatitis?
Has an auto-immune component and hyperproliferation
What are the 4 components of the epidermal cells
- Keratinocytes
- Melanocytes
- Langerhans cells
- gatekeepers, immune defense - Merkel cells
- nerve cells sensitive
Differentiate between primary and secondary lesions
Primary skin lesion:
- the early stage of the lesion (how it looks before evolving)
- Hard to classify/describe unless this is the patient’s FIRST presentation
Secondary lesion:
- the evolution of the primary lesion (after being modified by external forces/scratching, infection OR healing)
Differentiate between non-palpable and palpable skin eruptions
Non-palpable skin eruptions (flat)
- Macule: less than 1 cm
- Patch: 1cm+
Palpable skin eruptions (bumpy, non-flat)
- Papule: less than 1cm
(Pustule if filled with purulent material)
- Plaque: 1cm+
Define Psoriasis
What cells is it mediated by (3)
What other diseases is it associated with (3)
What is its clinic presentation
More common in male/females
A genetic, systemic, chronic and RELAPSING inflammatory skin disease that primarily affects skin/joints and can be altered by environmental factors
Mediated:
- T cells
- dendritic cells
- inflammatory cytokines
Associated with
- IBD
- Psoriatic Arthritis
- NAFLD (non-acloholic fatty liver)
- CAD (CVS, metabolic syndrome, stroke, MI)
- Malignancy (skin cancer)
- Psychological disorders (depression)
- Onycholysis (nail loosening/splitting)
Impacts
- Equal in male and female
Is sunlight and psoriasis a bad thing?
Sunlight is related to less frequent/severe psoriasis
Which demographic is psoriasis rare in?
Rare in N/S American aboriginal or indigenous people
What are the 2 age onsets of psoriasis
15-30 yo
50-60 yo
Pathogenesis of Psoriasis (3)
Genetic predisposition
Auto-immune activation
Triggers such as (stress, infections, drugs)
How do genetics play a role in psoriasis
Twins
1 parent
2 parents
- Identical twins have concordance rates of approx 80%
- risk of psoriasis with 1 parent affected: 14-20%
- risk of psoriasis with 2 parents affected: 41%
Which gene is Psoriasis linked to
PSORS1 mapped to chromosome 6
What environmental triggers are associated with psoriasis? (5) What drugs? (3)
- Injury/trauma ‘Koebner response”
- Smoking
- Alcohol
- Obesity
- Stress
Medications:
- Lithium
- Anti-malarials
- Beta blockers
T/F psoriasis reduces life expectancy
True
What are the 3 characteristic features of psoriatic plaque
- Hyperplasia of poorly differentiated epidermal cells (keratinocytes) with thickening of epidermis and formation of scales and plaques
- Angiogenesis (increased growth) of superficial blood vessels -> makes plaque red
- Infiltration of T-lymphocytes (T cells), dendritic cells, neutrophils, macrophages into psoriasis plaques
How long does shedding of keratinocytes in normal vs psoriasis patient take?
Normal: 26 days
Psoriasis: 4 days
Which inflammatory cytokines is associated with psoriasis? (5) What is secreting it?
Activated Th1 cells secrete
- IL 12
- IL 17
- IL 22
- IL 23
- TNF-alpha
What is the net effect of psoriasis?
What is the result?
Net effect of psoriasis:
- PREVENTS keratinocyte differentiation
- PROMOTES rapid/excessive keratinocyte and epidermal proliferation
Net result of psoriasis:
- LACK of cell maturation -> increased keratinization -> characteristic skin changes
Classification of Psoriasis
Plaque (P. Vulgaris)
Guttate
Pustular
Palmar Plantar
Scalp
Inverse (flexural)
Erythrodermal
Psoriatic Arthritis
Plaque (P. Vulgaris)
- red, thick, scaly, lesions with silvery scales
Guttate
- pink plaques or papules on truk
- presents after group A strep resp. infection
Pustular
- erythematous plaques with on palms/soles
Palmar Plantar
- psoriasis only onhands/soles
Scalp
- often first place plaques are seen
Inverse (flexural)
- plaques seen in skinfolds: groin, armpit, genitals
Erythrodermal
- severe, intense, generalized erythema and scaling entire body
- medical emergency
Psoriatic Arthritis
- involving joints
What is the auspitz sign (“Grattage” test)
Removing the scale of the plaque reveals smooth/red/glossy membrane with tiny dotted bleeding points
Very unique to psoriasis
T/F All patients with psoriasis will have pruritis
False
How do we measure the severity of Psoriasis? (3)
- BSA
- PASI
- index of severity plus extent of BSA involvening 4 key areas: (DOES NOT INCLUDE FACE, PALMS)
- head and neck
- upper limbs
- Trunk
- Lower limbs - PASI-CHANGE score
- change in severity from baseline
- PASI 75 = 75% decrease in severity
- PASI 100 = complete remission
What is the golden standard PASI-CHANGE score in psoriasis
PASI-75
75% improvement in 12 weeks
Define mild psoriasis in BSA
3-5%