Clinical characteristics of generalized idiopathic pruritus in patients from a tertiary referral center in Singapore.

BACKGROUND: Generalized idiopathic pruritus is a rarely studied heterogeneous condition, where patients with non-inflamed, non-pathologic skin complain of widespread pruritus.

METHODS: We had administered a detailed pruritus questionnaire, based on the short form of the McGill pain questionnaire, on 75 patients with this condition.

RESULTS: All 75 patients recruited with generalized idiopathic pruritus completed the questionnaire. In 92% of the patients, pruritus appeared on a daily basis. Most patients experienced pruritus at night (56%) and in the evening (61%) and 69% had difficulty falling asleep. Pruritus mainly involved the legs (79%), arms (76%) and back (68%). Accompanying symptoms were heat sensation (17%) and pain (13%). 80% had been prescribed antihistamines, of whom 56% obtained short-term relief. The sensation of itch has been reported to be crawling (33%), tickling (20%), stinging (19%) and burning (19%). Patients also reported that the itch was unbearable (73%), bothersome (72%), annoying (67%) and worrisome (45%). The worst-state VAS scores were significantly higher in patients who reported agitation (P = 0.006), difficulty in concentration (P= 0.010) and anxiety (P= 0.033).

CONCLUSION: This study describes the sensory and affective dimensions of generalized idiopathic pruritus, and this questionnaire has been found to be a useful tool for evaluating pruritus in this condition.