Hair Loss: A Well-Known Yet Understudied Symptom in Parkinson's Disease Patients During Dopaminergic Therapy.

Objective: Hair loss has been reported to occur during dopaminergic therapy in patients with Parkinson's disease. The mechanism by which dopaminergic therapy induces hair loss is not well understood. Dopamine receptors are present in the hair follicle, where they regulate melanin production. However, the role of dopamine receptors in hair growth is still not well understood. This study aimed to evaluate the prevalence of hair loss and identify factors associated with complaints of hair loss in patients with Parkinson's disease.

Methods: A cross-sectional design involving 495 Parkinson's disease patients was applied to evaluate hair loss status. Patients completed a questionnaire, and scalp/hair examinations were performed. Patients with underlying conditions that could affect hair loss and those prescribed medications known to increase the risk of hair loss were excluded. Finally, 291 patients (58.8%) were included for analysis.

Results: Among the 495 patients, 138 (27.9%) reported hair loss. Interestingly, more than half of the patients who complained of hair loss (79 out of 138) did not utilize treatments such as hair products, massage, dietary modifications, or alopecia medications. Hair inspection by a single investigator revealed objective hair loss in 263 patients (53.1%). An analysis of factors associated with hair loss complaints showed that the intake of dopaminergic medications with a levodopa-equivalent daily dose > 448 mg was associated with complaints of hair loss.

Conclusion: Dopaminergic medication is associated with hair loss complaints in Parkinson's disease patients.