Psoriasis
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Introduction
Psoriasis is a common chronic inflammatory condition affecting 1-2% people of all ages.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.
Causes and Risk Factors
The antigen remains elusive.
Pathophysiology
Psoriasis is a T cell mediated disease, involving keratinocyte proloferation accompanying inflammation and angiogenesis.
There is a strong association between psoriasis and HLA-C.
It is likely that CD4+ cells initiate the disease by interacting with antigen-presenting cells, activating epidermal CD8+ cells. This interaction gives rise to many cytokines, dominated by IL-12, IFN-g, and TNF. TNF is apparently responsible for much of the pathogenesis.
New plaques may develop at areas of skin trauma.
Signs and Symptoms
- history
- physical exam
History
Psoriasis is sometimes accompanied by:
- arthritis
- myopathy
- enteropathy (?)
- spondylitic joint disease
- AIDS
Psoriasis most commonly affects the skin of the elbows, knees, scalp, lumbosacral areas, bum cleft, and penis.
Typical lesions are well-demarkated, pink to salmon-coloured, covered by loosely adherent scales characteristically silver-white.
Nail changes occur in 30% of cases of psoriasis, leading to yellow-brown discoloration with pitting, dimpling, and separation of the nail bed (oncholysis)
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Diagnostic Imaging
Differential Diagnosis
Treatments
TNF antagonists can provide significant improvement in patients with psoriasis.
Consequences and Course
Resources and References
Topic Development
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