Psoriasis Flashcards
What is psoriasis and what causes
Chronic autoimmune disease due to hyper proliferation epidermis - keratinocytes and inflammatory cell infiltration
Genetic - HLA B13/17 / FH
Immune
Environment
What are environmental relations of psoriasis
Improved sunlight
Worsened Infection - strep throat Trauma - Koebner phenomena Stress Withdrawal steroid - can cause pustular IBD HIV Alcohol BB Lithium NSAID ACEI Quinine
What is the pathophysiology of psoriasis
Hyperproliferative epidermis causing abnormal build up and thickening
Stressed keratinocytes (due to trigger) + lymphocytes interact
Activation of dendritic cells by IL + TNF-A
Cause proliferation of keratinocyte + inflammation
Dendritic cells present antigen to T cell
VEGF = Angiogenesis and neovascularisation
T cells and neutrophils infiltrate
Cell cycle reduced from 28 days to 5
What is needed to diagnose psoriasis
Neutrophils
What does the histology show
Thick stratum corneum = hyperkeratosis Neutrophils in stratum Dilated capillaries T cell infiltration Psoriasiform hyperplasia
What are the 3 types of psoriasis
Type 1 = early onset - 20-30 (most common)
Type 2 = elderly
Type 3 = systemic
What is systemic associated with
Psoriatic arthritis = 30% - screen using PEST CVS disease VTE Increased risk of metabolic syndromes Psychosocial implications
What are S+S of psoriasis
Symmetrical Favour extensor - elbows, knee, scalp Sharp demarcated erythematous plaque Silvery scale Dry Well defined edge Raised and rough plaques Numerous widely disseminated papule and plaque Can have itch + pain Nail changes
What happens if psoriasis on skin folds e.g. anal area / breast
No scale forms
Can be misDx as yeast infection
What are the types of psoriasis
Chronic plaque = most common Guttate = Flexural (inverse) Pustular (palmo-plantar) Scalp Nail Arthritic Erythrogermic
What is chronic plaque psoriasis
Symmetric well demarcated plaques
Silvery scale
Affects extensor surfaces
Who is guttate psoriasis common in and what triggers
Children
Viral or bacterial
Typically strep throat 2-4 weeks prior
Raindrop lesions
What should you do
Check ASO titre - usually high
Treat if symptmati
No routine use of Ax
How does it present and what is outcome
Numerous small psoriatic tear drop lesions / papules
May resolve within 3-4 months
May trigger chronic and turn into plaques
How do you Rx
Most resolve
Topical Rx as per psoriasis
YVB
How does flexural present
Non scaly and smooth
Often confused with fungal as affects moist areas
Systemic fever
What triggers flexural
Dermatophyte / candida Bacterial Pregnancy Withdrawal of steroids Hypocalcaemia
How do you Rx
Combined steroid + anti-fungal to cover
How does pustular present
Thick scaly skin on palms and soles Pustules on hands and feet under skin Rapid erythema Systemically unwell - fever / elevated WCC Koebner
How do you Rx
Very resistant
Need to act quickly with systemic Rx
Medical emergency so admit to hospital
How does scalp psoriasis present
Pink hyperkeratotoic plaque
Thick adherent scales
What can it cause
Alopecia
What are nail signs in psoriasis
Pitting = most common
Onycholysis - separation from nail bed
Luekonychia
Oil spots
How do you Dx
Clinical or take culture to exclude fungal
Rarely present without psoriasis or arthritis (suggest fungal)
What is Koebner phenomenon
Skin lesions / conditions which appear at site of injury or trauma
What causes
Psoriasis Vitiligo Warts Lichen sclerosus Molluscum contagiosa
What should you avoid in erthyrodermic psoriasis
Medical emergency = admit
Extensive erythematous area leading to exfoliation
Topical steroid
Can make it turn pustular
What is main DDX
Red man syndrome - drug reaction to vancomycin
How do you Dx psoriasis
Clinical
Skin biopsy if atypical
What are differentials of psoriasis
Seborrheic dermatitis Lichen planus Mycosis fungiodes Bowen's Drug eruption Paget's Contact dermatitis Secondary syphillis
What is 1st line management in primary care
Avoid precipitating
Emollinets + soap substitute = always prescribe to reduce scale and itch
Coal tar cream
Vit D3 anaolgue + topical steroid once daily = 1st line
- Calcitriol
Increase 2x daily
Can add coal tar cream if no response
Topical dithranol if no response
Topical calcineurin inhibitor (tacrolimus) - only in adults
Salicyclic acid
What is 2nd line management in dermatology
Phototherapy
UVB = 1st line and very useful in guttate
PUVA
What is risk of UVB / PUVA
Skin ageing
SCC
What is 3rd step if all else fails / pustular / systemic involvement
Systemic retinoid
Immunosuppression - methotrexate / ciclosporin
Biologics = final step
If children must be guided by a specialist
What is 1st line immunosuppression
Methotrexate = 1st line
Ciclosporin
More helpful if arthritis
How do you Rx erythrodermic
Admit Fluid balance Bloods + IV access Thick greasy ointment / emollinet Systemic or biologics
What scales to measure severity
Psoriasis Area Severity Index
Dermatology Life Quality Index
What do they look at
SA
Plaque colour
Thickness
Scale
What is psoriasis associated with
CVD - Obesity - Hyperlipidaemia - Type II DM - Hypertension Smoking Alcohol Metabolic syndrome Depression Suicde
What drugs worsen
BB Lithium NSAID ACEI TNF-a Anti-malarial
What other factors worsen
Trauma
Alcohol
Withdrawal of systemic steroids
What are SE of methotrexate
Pulmonary and hepatic fibrosis
Myelosuppressio
Microcytic anaemia
What must be taken with it
Folic acid different day
