In a further study analyzing data from the Danish National Patient Registry in order to identify associations between rosacea and other medical conditions, a group of researchers led by Dr. Alexander Egeberg of the University of Copenhagen have now identified a potential relationship between rosacea and several autoimmune disorders known to be genetically linked. Drawing from the same database, the researchers had previously discovered associations between rosacea and Parkinson's disease, Alzheimer's disease and a form of brain cancer.

The new study included 6,759 patients with rosacea and a control group of 33,795 non-rosacea patients, all identified in the patient registry, which includes the medical histories of the entire population of Denmark. The groups were matched evenly by sex and age.

The investigators found that women with rosacea were 1.65 times more likely to have multiple sclerosis (MS), 2.03 times more likely to have celiac disease, 2.14 times more likely to have rheumatoid arthritis (RA), and 2.59 times more likely to have type 1 diabetes than women who didn’t have rosacea. In male patients, there was only a significant association between rosacea and rheumatoid arthritis, with men who suffered from rosacea 2.05 times more likely to have RA.

A genome-wide association study sponsored by the NRS found genetic variations believed to be linked to rosacea were in the same region of the genome associated with type 1 diabetes and celiac disease. Other genetic studies have found commonality in the genetic variants associated with certain autoimmune diseases like RA, MS, type 1 diabetes and celiac disease, though not necessarily evidence that they are related or affect one another.

This potential genetic and clinical connection between rosacea and autoimmune disorders has spurred some physicians to speculate that it might make sense to ask rosacea patients if they’ve experienced the symptoms of these autoimmune diseases. In an editorial published alongside the Danish study in the Journal of the American Academy of Dermatology, Dr. Graeme Lipper, assistant professor of dermatology at the University of Vermont Medical College wrote, “It would be easy to screen patients with rosacea (especially women) for potential autoimmune comorbidities by asking a few simple, targeted questions: ‘Do you get numbness and tingling or weakness in your hands? Gastrointestinal upset or diarrhea when you eat wheat or other sources of gluten? How about joint pain and stiffness?’”

The Danish investigators noted that it is possible the association between the diseases is due to shared lifestyle or environmental factors, rather than a genetic link. Another limitation of this study was that researchers were unable to distinguish between the four subtypes of rosacea seen in patients. There could be a positive association between certain subtypes of rosacea and certain autoimmune diseases, but not necessarily an association between each subtype of rosacea, they said. They added that further research is needed to determine the nature of the relationship between rosacea and autoimmune diseases.

Reference:
Egeberg A, Hansen PR, Gislason GH, Thyssen JP. Clustering of autoimmune diseases in patients with rosacea. J Am Acad Dermatol. 2016 Apr;74(4):667-672.e1. doi: 10.1016/j.jaad.2015.11.004. Epub 2016 Jan 30.