Psoriasis Flashcards
(27 cards)
Which gene is most commonly related to psoriasis?
PSORS 1 location on chromosome 9 (6p21.3)
Which HLA antigen gives a person a 10 fold increase of developing psoriasis?
HLA-Cw6
What is the pathogenesis of psoriasis?
Hyperproliferation of epidermal cells
T lymphocytes move out of the blood vessels in the skin and into the dermis
Higher levels of calcium-binding protein found in psoriatic plaques
Name some precipitating factors of psoriasis?
- Emotional stres
- Infection - strep throat causing guttate psoriasis
- Drug - Beta-Blockers, lithium, antimalarials, withdrawal of topical or systemic steroids
- Alcohol
- Trauma - Koebner phenomenon
- Smoking
- HIV/AIDS
(8. UV irradiation - 10% worsen)
What are the histological features of psoriasis?
- Parakeratotic stratum corneum (contains nuclei – normally none)
- Absence of granular layer
- Expanded prickle cell layer
- Large capillary vessels in papillary dermis
- Leucocytes – Munro microabscesses in stratum corneum
What are the psoriasis sub-types?
- Chronic plaque
- Guttate
- Scalp
- Flexural
- Palmoplantar psoriasis
- Palmo plantar pustulosis
- Erythrodermic
- Pustular - generalised
- Nail
- Psoriatic arthritis
Which areas are most commonly affected by chronic plaque psoriasis?
Extensor aspects of knees, elbows, sacrum and scalp. Often symmetrical
What is Auspitz’ sign?
Removing scale reveals pin-point bleeding - positive in chronic plaque psoriasis
What is Koebner phenomenon?
Skin lesions which appear at the site of trauma 2-6 weeks after trauma sustained
What is the typical age of someone who develops guttate psoriasis?
15-25 years old
Guttate psoriasis is classically triggered by what?
Streptococcal sore throat - develop multiple small psoriatic lesions on trunk 7-10 days later
What is the treatment for guttate psoriasis?
Emollients
Topical tar
Phototherapy
What is the treatment for scalp psoriasis?
Olive oil
Tar shampoos e.g. Polytar(R)
Coconut oil e.g. Cocois(R)
Where on the body is flexural psoriasis typically found?
Groin, axillae or inframammary
Describe flexural psoriasis?
Shiny, red, well-demarcated plaques
What is the treatment for flexural psoriasis?
Mild topical steroid / antifungal preparations (e.g. Trimovate® cream, Canesten HC® cream)
What is the treatment for palmoplantar psoriasis?
Topical tar preparations Salicylic acid Topical steroids Phototherapy Systemic immunosuppressants (Palmolantar psoriasis is difficult to treat)
Palmoplantar pustulosis is stronger associated with what cause?
Smoking
Describe palmoplantar pustulosos?
Sterile yellow pustules fading to brown macules
What is erythrodermic psoriasis?
Erythroderma covering >90% of the skin in a patient wit psoriasis
What are some of the causes of erythrodermic psoriasis?
Withdrawal of potent topical or systemic steroids
Drug reactions
Ultraviolet burns etc
What are the complications of erythrodermic psoriasis?
Hypothermia Cardiogenic shock Dehydration Anaemia Hypoproteinaemia
What is the treatment for erythrodermic psoriasis?
Fluid balance
Bed rest
Emollients
Systemic immunosuppressants
Describe pustular psoriasis?
Generalised, painful skin, fever, malaise, sterile pustules
