Prevalence and Characteristics of Itch in Patients with Parkinson’s Disease
Rami H Mahmoud1, Sarah Marmol1, Matthew Feldman1, Gil Yosipovitch1, Ihtsham Haq1
1University of Miami
Objective:
To characterize itch in patients with Parkinson’s disease (PD) and correlate it with disease characteristics.
Background:
Patients with PD report increased pain sensitivity. Given that itch and pain share some sensory pathways, it is possible that itch sensation is also altered. Prior work has found a significantly larger area of itch hypersensitivity in PD patients following histamine application, suggesting a possible alteration in central processing. Moreover, PD is commonly associated with a range of itchy disorders including seborrheic and perioral dermatitis, bullous pemphigoid, rosacea, hypo- and hyperhidrosis, and medication side effects.
Design/Methods:
We surveyed 38 patients with PD using a modified numeric itch scale. Patients were included in the itch+ group if they reported chronic history of itch on the questionnaire. We collected demographic data by retrospective chart review.
Results:
47% of patients (18/38) reported itching. Average age, disease duration, and levodopa equivalent daily dosing (LEDD) were not statistically significant between itch and non-itch groups.
Among patients with itch, average duration was 13.2yrs, PD duration was 6yrs. Males were 2.86 times more likely than females to report chronic itch(p = 0.04).
There was a slight negative correlation between PD duration and itch duration(r=-0.22), as well as between LEDD and itch duration(r=-0.34). A weak positive correlation was found between LEDD and itch severity(r=0.05).
On a 10-point scale, average 24-hour itch severity was 5, average 24-hour worst itch was 6.19. Most common characteristics: burning quality(50%); localized distribution(88.24%); most common location was the back(55.56%); unilateral orientation(33%); duration of itch episodes 0-2 hours(93.75%).
Conclusions:
Our findings suggest itch is relatively common amongst PD patients and more common in men than women. This contrasts with a lifetime prevalence of 22% and female predominance in a general population sample. Correlations between disease characteristics and itch were not statistically significant and further research is indicated.