In Chinese Medicine this condition is believed to be caused by blood-heat and internal wind which are caused by stress.
ACUPUNCTURE FOR PSORIASIS
Acupuncture treatment and Chinese herbal medicine are used to cool the blood, to remove the stagnation and toxins as well as to relieve the stress in order to calm the itchiness characteristic from this condition.
See what the British Acupuncture Council says about treating psoriasis with acupuncture.