Review Outlines Dermatologic Implications in Parkinson Disease

Parkinson disease (PD), the second most common progressive neurodegenerative disorder, is a multisystemic disorder characterized by both motor and nonmotor symptoms (NMS). Authors of a review article published in Parkinsonism & Related Disorders highlight the prevalence of dermatologic disorders in PD, which they note can be divided into 2 major groups:

• noniatrogenic disorders, including melanoma, seborrheic dermatitis, sweating disorders, bullous pemphigoid, and rosacea; and
• iatrogenic disorders related either to systemic adverse effects of antiparkinsonian medications or to the delivery system of antiparkinsonian therapy, including carbidopa/levodopa, rotigotine and other dopamine agonists, and deep brain stimulation.
  

In examining skin disorders associated with PD and antiparkisonian therapies, the researchers additionally sought to assess the role of skin in pathogenic, diagnostic, and therapeutic considerations in PD.

Notably, recent advances in the understanding of α-synuclein, an abnormal protein suggested to have a central role in the pathogenesis of PD, now delineate its presence in peripheral tissue, including skin. In fact, a recent study found that a skin test to detect clumping of α-synuclein may assist in improving earlier detection of the condition, a process that currently relies on clinical signs and symptoms.

“This small protein (140 amino acids), involved in a variety of cellular mechanisms, undergoes misfolding and aggregation in the brain as well as in the skin, and may contribute to some non-motor symptoms,” explained the researchers.

Adding to the pathogenic implications that skin may have, the review authors say that the presence of some skin disorders, particularly seborrheic dermatitis and sweating dysfunction, may be caused by peripheral autonomic dysfunction and can predate onset of motor symptoms in PD. Moreover, studies have found that patients with PD are at an increased risk of melanoma, which has led to some organizations to recommend that those with PD visit a dermatologist at least once a year for a skin check.

“This recommendation may be especially relevant in patients with PD who have a particularly high risk for developing melanoma such as Caucasian individuals with frequent and intense sun exposure, the greatest risk factor for melanoma,” the review authors wrote.

Concluding with therapeutic considerations in PD, the researchers highlighted the potential of pluripotent stem cells derived from skin fibroblasts among patients. A prior study exhibited the efficacy of this approach, in which a novel treatment that reprogrammed the skin cells of a single patient with PD to replace cells in the brain improved symptoms over 24 months. However, the investigators of that study cautioned that a longer, more diverse clinical trial is warranted to confirm findings.

Reference

Niemann N, Billnitzer A, Jankovic J. Parkinson’s disease and skin. Parkinsonism Relat Disord. Published online November 20, 2020. doi:10.1016/j.parkreldis.2020.11.017