The skin as a sentinel organ for neurodegeneration: An underrecognized target for dementia prevention

Dementia prevention increasingly requires attention to modifiable systemic inflammatory stressors. In older adults, bullous pemphigoid (BP), herpes zoster (HZ), psoriasis, atopic dermatitis (AD), rosacea, prurigo nodularis (PN), and chronic pruritus are not merely disorders limited to the skin; they may signal or amplify neuroimmune vulnerability. Observational studies link BP with dementia and Alzheimer's disease, HZ with incident dementia and vascular cognitive injury, and psoriasis, AD, rosacea, or PN with smaller but biologically plausible cognitive risks. The proposed skin-brain axis integrates cytokine spillover, endothelial activation, blood-brain barrier dysfunction, BP180/ BP230 autoantigen sharing, varicellazoster virus neurotropism and vasculopathy, barrier failure, dysbiosis, itching-induced fragmented sleep, and medication or frailty-related cognitive toxicity. Clinically, cognitive impairment also worsens skin surveillance, hygiene, topical adherence, and recognition of pain, itching, infection, or blistering. Although causality and dementia prevention remain unproven, the evidence justifies proactive dermatological care in older adults and greater cognitive vigilance in older patients with severe inflammatory or pruritic dermatoses. Recombinant zoster vaccination, prompt antiviral therapy, steroid-sparing BP strategies, modern anti-inflammatory treatment for AD, psoriasis, and PN, and systematic attention to sleep, itching, caregiver capacity, and the medication burden are practical, low-regret steps while prospective brain-relevant trials are developed. This translational framework highlights mechanisms clinicians can now interrupt and endpoints investigators can soon measure. We propose that the skin should be recognized as a sentinel organ for neurodegeneration and that dermatological disease represents a potentially modifiable contributor to cognitive decline.