Bullous pemphigoid (BP) is an autoimmune blistering skin disease with increasing incidence. BP is associated with neurological disorders, but it has not been established, what subtypes of dementia and stroke are associated with BP, and what is the temporal relation between these diseases. Also, the association between BP and psychiatric disorders is controversial. We conducted a retrospective nationwide study, using the Finnish Care Register for Health Care diagnoses between 1987 and 2013. The study population of 4524 BP patients were compared with 66138 patients with basocellular carcinoma (BCC), neurological and psychiatric comorbid disorders were evaluated for both groups, and associations were estimated by Cox regression and logistic regression analyses. The strongest risk of developing BP was found after diagnosis of multiple sclerosis (MS) (OR=5.9, 95% CI 3.9-8.5). Among psychiatric diseases, the corresponding risk was strongest in schizophrenia (OR=2.7, 95% CI 2.0-3.5), and as a novel finding, also personality disorders (OR=2.2, 95% CI 1.3-3.3) preceded BP. In conclusion, many psychiatric disorders, especially schizophrenia, carry heightened risk for BP. Furthermore, several neurological diseases which cause central nervous system inflammation or degeneration were related to BP, and the association was strongest between MS and BP.Bullous pemphigoid (BP) is an autoimmune skin disease with incidence varying between 0.25 and 4.28/100.000 per year 1-3 . The age-adjusted incidence of BP has been reported to be on the rise 1-3 . BP typically presents with severe itching and blistering of the skin, but in up to 20% of patients blisters are completely absent and only excoriations or eczematous, urticated lesions are observed 4 . BP typically affects elderly people, has many comorbidities and carries an elevated risk of death compared with the general population of the same age [1][2][3][4] . The pathogenesis of BP is characterized by autoantibodies directed against the hemidesmosomal components between the basal keratinocytes of the epidermis and the extracellular matrix of the dermis, resulting in subepidermal blister formation. The main autoantigen is bullous pemphigoid antigen 180 (BP180, also known as BPAG 2 or collagen XVII), though BP patients may also have autoantibodies against bullous pemphigoid antigen 230 (BP230 or BPAG1), another hemidesmosomal protein 4 . Several studies have established an association between BP and neurological disorders, especially stroke, dementia and Parkinson's disease [5][6][7][8] . The mechanism behind this association has been suggested to be an autoinflammatory reaction against BP180 or the neuronal isoform of BP230 in the human brain 9,10 . However, previous studies did not specify the types of dementia or cerebrovascular stroke. Neurological disorders precede BP 5,6 , but it is unclear, whether the risk of developing neurological disorders is elevated after a diagnosis of BP.