Research has clearly shown that psoriasis is more than skin deep and is linked to a host of systemic comorbidities. Rosacea is following a similar trajectory with evidence building on its connection to glioma, dementia, and more. An expert weighs in.

Alexander Egeberg, MD, PhD is in the department of dermato-allergology at Herlev and Gentofte Hospital, in Copenhagen, Denmark.

What are some of the diseases linked to rosacea?

Dr. Egeberg: There is strong evidence linking rosacea with gastrointestinal disorders, e.g. infection with Helicobactor pylori and inflammatory bowel disease. Moreover, emerging data suggest an association with neurological and psychiatric disorders such as migraine, depression, anxiety, Parkinson disease, and dementia.

What’s the common denominator?

Dr. Egeberg: The reason for these links is not yet fully understood. Common genetic susceptibility, environmental factors, and proinflammatory mediators and antimicrobial peptides have been suggested as potential explanations, but further studies are needed to fully determine this.

Could you tell us about your recent study regarding rosacea and dementia risk?

Dr. Egeberg: We looked at the entire adult Danish population over a 15-year time period. When comparing rosacea patients with the general population, those with rosacea had a slightly higher risk of dementia, in particular Alzheimer’s disease. Certain proteins and inflammatory processes have been found in increased levels in the skin of patients with rosacea, and these have also been linked to dementia. While this may be one potential explanation, we cannot say for sure that this is the cause.

Editor’s note: Another study by Dr. Egeberg, et al. found that rosacea may increase risk for glioma. This association could be mediated, in part, by mechanisms dependent on matrix metalloproteinases, which may play a role in both glioma and rosacea. These findings were published online in JAMA Dermatology. See page 54 for more on these and other studies.

What should practicing dermatologists tell rosacea patients regarding dementia risk?

Dr. Egeberg: Our findings should not cause panic. It is important to remember that while a link may exist, the absolute risk is still quite low. However, patients and physicians should, of course, pay attention to early signs of decline in cognitive function, but they should bear in mind that having rosacea is not a guarantee that an individual will develop dementia.

Will treating rosacea mitigate the risk of
comorbidities?

Dr. Egeberg: This is an interesting question. There is some data to suggest that treatment with tetracyclines (including doxycycline) might have a small protective effect. However, the current sum of evidence is not sufficient to provide such recommendations, and further studies are needed to confirm if treating rosacea will impact these comorbid conditions.

What are some of the more pressing research questions about these links?

Dr. Egeberg: While the underlying cause for these associations warrants further studies, our team is currently investigating the potential effects of anti-rosacea therapy (e.g. tetracycline) on these comorbidities. n