Seborrheic Dermatitis Is Related to Motor Symptoms in Parkinson's Disease

Background and Purpose Parkinson's disease (PD) patients present with numerous motor and nonmotor symptoms. Seborrheic dermatitis (SD) is reported in 18.6%-59% of PD patients. However, the etiology of SD in PD patients remains unknown. The aim of this study was to determine how motor and nonmotor symptoms, age, sex, and levodopa-equivalent daily dose (LEDD) influence the appearance and severity of SD in PD patients, and then discuss about SD possible etiology based on the obtained results. Methods Motor symptoms were evaluated using the Unified Parkinson's Disease Rating Scale part III and nonmotor symptoms were evaluated using the Parkinson's Disease Sleep Scale, Scales for Outcomes in Parkinson's Disease-Autonomic Dysfunction, and Non-Motor Symptoms Questionnaire. LEDD was calculated and demographic data on age, sex, disease duration, and symptoms of SD prior to a PD diagnosis were collected. A dermatologist evaluated the skin for SD using the Seborrhea Area and Severity Index. Results SD was present in 36.1% of the PD patients. There were positive correlations between age, motor-symptoms severity, and SD. After adjusting for age, disease duration, and sex, there remained a positive correlation between the severity of motor symptoms and SD. Patients with moderate-to-severe motor symptoms had more-severe SD symptoms, and their risk of developing SD was 1.8-fold higher. There was no correlation between SD and autonomic dysfunction, sleep disturbances, or other nonmotor symptoms, and no sex difference. Conclusions In PD, SD is related to motor symptoms.