The Skin and Parkinson's Disease: Review of Clinical, Diagnostic, and Therapeutic Issues

Background: Parkinson's disease (PD) and the skin are related in a number of ways, including clinical abnormalities of the disease itself and skin-related side effects of dopaminergic medication, pumps, and surgical therapies. Recent advances in understanding the role of alpha-synuclein suggest skin biopsies as a potential diagnostic or even a premotor marker of PD. Methods: The PubMed database was searched for publications up to October 2015, and the current evidence on skin-related issues in PD was comprehensively summarized. Results: The evidence was summarized on the prevalence, etiology, and management of seborrheic dermatitis, sweating dysfunctions, bullous pemphigoid, and malignant melanoma, as well as therapy-related skin disorders, especially those observed in amantadine, rotigotine, apomorphine, and levodopa/carbidopa intestinal gel therapies and deep-brain stimulation. Skin biopsies evaluating the presence of alpha-synuclein, the density and morphology of cutaneous nerves, and skin fibroblast functions also are discussed. Conclusions: Skin disorders are a common manifestation of PD. However, the exact pathophysiology and prevalence of these disorders are not well understood, and more systematic research is needed in this regard. Peripheral tissue biopsies as a diagnostic marker of PD are an exciting avenue in future PD research, although multiple caveats and pending issues need to be solved before they can be used in routine clinical practice.