Psoriasis Flashcards
(33 cards)
What is psoriasis
Chronic, genetically determined, immune-mediated, inflammatory skin condition, usually characterised by well defined, scaly, plaques
Clinical features of psoriasis (describe the characteristics)
Lesions are red, inflamed, silvery-white scaly, and circumscribed papules and plaques;
Causative factors of psoriasis (7)
Genetics - strong predisposition
Immunology - overactive immune system, excessive production of cytokines
Infection - strep, candida
Environmental trigger
Drug induced - lithium, beta blockers
Trauma
Sunlight
Pathophysiology of psoriasis
hyperproliferation involving a complex cascade of inflammatory mediators (excessive production of TH1 cytokines)
-causing basal and suprabasal cells to excessively divide and migrate from the basal layer to the stratum corneum in just a few days compared to normal turnover of 28 days
What cytokines are involved mediating psoriasis
TH1 cytokines, esp TNF-alpha
Histological features of psoriasis
Hyperkeratosis (thickened stratum corneum)
Parakeratosis (keratinocytes with nuclei in stratum corneum)
Neutrophils in stratum corneum
Hypogranulosis - no granular layer (needed as a physical barrier)
Acanthosis (thickening of squamous cell layer)
What infiltrating cells can be seen on histology of psoriasis
T cells
Subtypes of psoriasis
Chronic plaque - commonest Flexural Acute Guttate Scalp Palmoplantar Nail Pustular Erythrodermic
Clinical features of chronic plaque psoriasis
- characteristics of plaque
- where it’s found
Raised inflamed thick plaque lesions with a superficial silvery-white scaly eruption
Legs/back/knee/elbow/foot/scalp
Commonest subtype of psoriasis
chronic plaque
Psoriasis can have implications on what organ system
Cardio
Clinical features of guttate psoriasis
- characteristics of lesions
- where the lesions are found
Widespread, erythematous, fine, scaly papules (water drop appearance)
-on trunk, arms, and legs
Guttate psoriasis onset is usually acute or chronic
Acute
Lesions due to guttate psoriasis often erupt following a period of what
upper resp infection, e.g. throat infection
1st line treatment of guttate psoriasis
phototherapy
Several months’ history of a rash on her hands and feet, she works as a masseuse.
Examination - skin on pass and soles appear thick, scaly, red with yellowish brown lesions at the edges
What’s the diagnosis
Palmo-plantar psoriasis
A 14 year old boy presents with an acute onset of a generalized eruption.
O/E he has 2-5 mm multiple salmon colour papules with a fine scale worse on the trunk and proximal extremities.
On direct questioning his mother says that he has had a throat infection 2-3 weeks prior to the rash
Diagnosis?
Guttate psoriasis
54 year old male presents with a 15 year history of scaly plaques on both elbows. Over the last few months the rash has spread to involve large areas of his body
O/E he has large salmon coloured plaques on his arms, legs and back with thick scale
Diagnosis?
Chronic plaque psoriasis
27 year old lady presents to your clinic complaining of severe dandruff; starting to spread to face as well.
O/E you note thick hyperkeratotic plaques in the scalp with some pitting of the nails. She also has 2 small plaques of scaly rash on the cheeks
Diagnosis
Scalp psoriasis
Scalp psoriasis can be confused with what other condition which commonly causes dandruff as well
Seborhoeic dermatitis
Clinical features of nail psoriasis (2)
- Pitting
2. Onycholysis
36 year old patients presents to you complaining of several months history of RASH IN ARMPITS. He has been treated with topical and oral anti-fungal agents in the past with out any benefit
O/E you note shiny pink to red sharply demarcated plaque with NO SCALING
Diagnosis?
Flexural/inverse psoriasis
Flexural psoriasis lacks what feature most forms of psoriasis have
scaling
50 year old lady presents with an ACUTE onset of generalised red, tender patches.
On closer inspection of the patches multiple yellow PUSTULES are seen
Diagnosis?
Pustular psoriasis (unstable acute emergency)
