Chronic pruritus in multiple sclerosis and clinical correlates

Background To date, little is known about the prevalence of itch in multiple sclerosis (MS) and its characteristics. Objectives In this cross-sectional study, we assessed the prevalence, intensity and characteristics of chronic pruritus in MS patients and its effect on quality-of-life and association with MS symptoms, clinical signs, comorbidities and MRI findings. Methods MS patients presenting to an outpatient neurology clinic were asked about their current symptoms. Those who experienced chronic pruritus were administered the Standardized Itch Questionnaire and Itch Quality of Life forms. All patients' medical records were reviewed. Patients with any medical conditions associated with chronic itch were excluded. Results Seventy-seven total MS patients were included, and 27 (35%) reported pruritus. The average itch NRS severity was 5.42 (range 0-10). The most affected body parts were the extremities, face or scalp, and trunk. Itch was characterized as acute (74%), paroxysmal (59%) and tingling (55%). Heat (52%) was the most common aggravating factor, while cold temperatures had no effect. Compared with MS patients without itch, itch patients reported more fatigue (77% vs 44%, p = 0.004), heat sensitivity (48% vs 20%, p = 0.0177), cognitive impairment (62% vs 26%, p = 0.0029) and depression or anxiety (48% vs 16%, p = 0.0063). Additionally, itch patients had more T2 hyperintensities in the posterior cervical cord and anterior pons/ventromedial medulla (74.1% vs 46.0%, p = 0.018 and 29.6% vs 8.0%, p = 0.020, respectively). Finally, T2 hyperintensities in the anterior pons/ventromedial medulla were strongly associated with itch localized to the face or scalp (OR 11.3, 95% CI 1.6-78.6, p = 0.025). Conclusion MS patients experience paroxysmal neuropathic pruritus that is most frequently localized to the extremities, face or scalp. Patients with itch were more likely to have MS-related comorbidities and demyelinating lesions in the spinal cord or brainstem.