Lecture Notes Dermatology - Graham-Brown, Robin, Burns, Tony

Psoriasis 71
Figure 8.2 Psoriatic plaque on the
elbow.
Figure 8.4 Nail pits in psoriasis.
Figure 8.3 Scalp psoriasis.
It is often said that psoriasis is not itchy, but
in our experience a significant number of patients
complain of severe itching, and most experience
some itch at times. In fact, the Greek psora
actually means itch. Some forms of psoriasis
(e.g. guttate, flexural) are more prone to cause
irritation.
Scalp p soriasis
Scalp involvement is very common: indeed the
scalp may be affected alone. It can be difficult to
distinguish scalp psoriasis from severe seborrhoeic
dermatitis (see also Flexural psoriasis), but
psoriasis lesions are generally thicker. As a rule of
thumb, if you can feel scalp lesions as well as see
them, they are probably psoriasis.
Involvement varies from one or two plaques to
a sheet of thick scale covering the whole scalp
surface (see Figure 8.3 ). Rarely, the scale becomes