Should Rosacea Patients Be Screened for Autoimmune Diseases?

Clustering of Autoimmune Diseases in Patients With Rosacea

Egeberg A, Hansen PR, Gislason GH, Tyssen JP
J Am Acad Dermatol. 2016;74:667-672

The inflammatory skin disorder rosacea presents during adulthood with centrofacial erythema and flushing; telangiectatic mats; papules, pustules, and cysts; and phymatous changes. The National Rosacea Society Expert Committee delineates four subtypes of rosacea: erythematotelangiectatic, papulopustular, phymatous, and ocular, although these patterns often overlap in clinical practice.^[1] In addition, there are rarer pediatric and granulomatous presentations. Rosacea affects persons of all ethnicities, but light-skinned people of European descent are most prone, with one Swedish study showing a prevalence of 10%.^[2]

Rosacea—once thought to be an inflammatory disorder of pilosebaceous units triggered by infectious agents, such as Propionibacterium acnes or Demodex folliculorum—is now characterized as hyperreactivity of innate cutaneous immunity that is triggered by a range of environmental, dietary, hormonal, and lifestyle factors.^[3] Furthermore, this cutaneous sensitivity has a strong hereditary component, with recent genome-wide association studies showing clustering of the genetic risk loci for rosacea, type 1 diabetes (T1DM), celiac disease (CD), rheumatoid arthritis (RA), and multiple sclerosis (MS).^[4,5]

Such genetic clustering, although intriguing, does not prove any clinical association. To address this point, Egeberg and colleagues conducted a population-based case-control study looking for any link between rosacea and T1DM, CD, MS, and RA over a 15-year period. This large Danish study included 6759 patients with rosacea and 33,795 age- and sex-matched controls (mean age of case patients and controls, 40.2 years; 63.2% women). Patients with lupus were excluded from the study.

Egeberg and colleagues' statistical analysis, which controlled for socioeconomic and smoking status, detected the following statistically significant associations:

In women, rosacea was associated with T1DM (odds ratio [OR], 2.59), CD (OR, 2.03), MS (OR, 1.65), and RA (OR, 2.14).
In contrast, rosacea was associated with only RA in men (OR, 2.05).
There was no association between rosacea and colon cancer (checked to control for any potential detection bias).

Viewpoint

One problem with genome-wide association studies is that they reveal only potential genetic linkage. In contrast, Egeberg and colleagues' case-control study takes this one step further, showing that Scandinavian women with rosacea are more likely to have T1DM, MS, and CD, and both men and women are more likely to have RA. The study could not, however, differentiate between different subtypes of rosacea or rosacea severity. This is a significant limitation, because the observed association may apply only for a specific rosacea subtype or individuals with severe inflammation.

Should all patients with rosacea be screened for autoimmune diseases, such as T1DM, MS, RA, and CD? That depends on the type of screening. Given the high prevalence of rosacea, across-the-board laboratory testing would come with a huge, unnecessary price tag. However, 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?" As for screening for glucose intolerance, that should be done routinely for all adults.

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