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Chapter 1: INTRODUCTION
1.1. Clinical and subclinical features of psoriasis:
1.1.1. Clinical features:
- Cutaneous lesion: A specific lesion is a non-infiltrated,
erythematous, well-defined plaque with silvery scales
on the surface. The size of the lesion can vary from
pinpoint papules to plaques covering large area of the
body. Psoriasis has a tendency to be symmetrical, which
is a good characteristic for diagnosis. However,
unilateral lesion can also appear. Common lesions
include: macules, plaques of erythema and scale
(sometime papules with scale).
- Sites of lesion: Lesions are generally symmetrical. The
sites of predilection of the characteristic plaques include
scalp, beyond the hairline, knee, elbow, extensor of the
arms and legs. Psoriasis lesions can appear on cutaneous
injuries, irritation, rubbing (for example scratching,
chafing, injection) called Kebner phenomenon.
- Nail lesions: Nail lesions are very common (30-50%
of all cases). It happens in all or many nails