Abstract
Pruritus has not been considered as the most important symptom of
psoriasis. In the present thesis various methodologies have been used to
investigate this symptom in psoriasis.
The focus groups created a proper atmosphere for discussion on different
aspects of pruritus in psoriasis. Pruritus was most common on the lower
back and legs. Stress, cold weather and skin dryness were considered as
the most common worsening factors for the condition. Sunbath and
application of emollients with or without corticosteroids and
calcipotriol cream were suggested as factors that relieved pruritus.
Quality of life was affected in some patients.
A comprehensive questionnaire was used to investigate in detail about
pruritus in psoriasis. The frequency and intensity of pruritus were
higher in women. Lower leg and scalp were reported as being the most
commonly affected sites. Major aggravating factors were stress and
dryness of skin. Sun, sleep and vacation could relieve to the condition.
The most common anti-pruritic treatments used by the patients were
topical glucocorticoids, vitamin D and emollients, while antihistamines
were used by a small number of patients. Mood, concentration and sleep
were negatively affected by pruritus.
Substance P, neurokinins A (NKA), B (NKB) and NK-2 receptor (R), reactive
nerves and substance P, NKA, NKB and their respective receptors NK-1,
NK-2 NK-3 reactive inflammatory cells were more numerous in lesional than
non-lesional psoriasis and healthy control skin, respectively. The
pruritus intensity and number of NK-2R positive cells in lesional
psoriatic skin were significantly correlated.
Intradermally injected substance P induced pruritus, flare and wheal in
psoriasis patients. Substance P (10-5 mol/L) induced a tendency to larger
intensity of pruritus in lesional than non-lesional psoriatic skin.
Histamine produced a shorter itch latency period in lesional and smaller
wheal in non-lesional psoriasis skin compared to healthy individuals.
In conclusion, pruritus is one of the common symptoms of psoriasis.
Members of the tachykinin family might play an important role in the
pathogenesis of pruritus in this disease.
