Cohort study of neurological and psychiatric morbidity in dermatitis herpetiformis and celiac disease

Background: Neurological and psychiatric morbidity has been associated with celiac disease but has been scarcely studied in dermatitis herpetiformis (DH), a cutaneous manifestation of celiac disease. Hence, this cohort study aimed to investigate neurological and psychiatric morbidity in patients with DH and celiac disease. Methods: The study comprised 368 DH patients and 1,072 celiac disease patients without DH and their 1,099 and 3,197 refences, matched 1:3 on age, sex, calendar period and place of residence. Their neurological and psychiatric morbidity was studied using the Care Register for Health Care and international classification of diseases codes. Hazard ratios (HR) were calculated using Cox proportional hazard model. Results: In DH the risk for any neurological disease was not statistically significantly increased (HR 1.27; 95% CI 0.94–1.71), but Alzheimer’s disease and extrapyramidal diseases were found to be more common in DH when compared with their references. In contrast, in celiac disease excess risks for any neurological disease (HR 1.31; 95% CI 1.09–1.56) and particularly for migraine and headaches were detected. The risk for any psychiatric disease was found to be decreased in DH (HR 0.65; 95% CI 0.47–0.90), as were the risks for anxiety and substance abuse. In celiac disease, increased risks for any psychiatric disease (HR 1.20; 95% CI 1.01–1.42), depression, and anxiety disorders were noted. Conclusions: The neurological and psychiatric morbidity of patients with DH and celiac disease patients without DH seems to differ, but the reasons for this varying disease burden remain yet unidentified.