Long-Term Risk for Some Skin Disorders Increased After COVID

A population-based study has shown a slightly elevated risk for patients’ developing skin disorders, including alopecia areata (AA), alopecia totalis (AT), vitiligo, and bullous pemphigoid (BP), more than 6 months after COVID-19 infection. In addition, the authors reported that the COVID-19 vaccination appears to reduce these risks.

The study was published in JAMA Dermatology on November 6.

‘Compelling Evidence’

“This well-executed study by Heo et al. provides compelling evidence to support an association between COVID-19 infection and the development of subsequent autoimmune and autoinflammatory skin diseases,” wrote authors led by Lisa M. Arkin, MD, of the Department of Dermatology, University of Wisconsin School of Medicine and Public Health in Madison, Wisconsin, in an accompanying editorial.

Using databases from Korea’s National Health Insurance Service and the Korea Disease Control and Prevention Agency, investigators led by Yeon-Woo Heo, MD, a dermatology resident at Yonsei University Wonju College of Medicine, Wonju, Republic of Korea, compared 3.1 million people who had COVID-19 with 3.8 million controls, all with at least 180 days’ follow-up through December 31, 2022.

At a mean follow-up of 287 days in both cohorts, authors found significantly elevated risks for AA and vitiligo (adjusted hazard ratio [AHR], 1.11 for both), AT (AHR, 1.24), Behçet disease (AHR, 1.45), and BP (AHR, 1.62) in the post-COVID-19 cohort. The infection also raised the risk for other conditions such as systemic lupus erythematosus (AHR, 1.14) and Crohn’s disease (AHR, 1.35).

In subgroup analyses, demographic factors were associated with diverse effects: COVID-19 infection was associated with significantly higher odds of developing AA (for both men and women), vitiligo (men), Behçet disease (men and women), Crohn’s disease (men), ulcerative colitis (men), rheumatoid arthritis (men and women), systemic lupus erythematosus (men), ankylosing spondylitis (men), AT (women), and BP (women) than controls.

Those aged under 40 years were more likely to develop AA, primary cicatricial alopecia, Behçet disease, and ulcerative colitis, while those aged 40 years or older were more likely to develop AA, AT, vitiligo, Behçet disease, Crohn’s disease, rheumatoid arthritis, systemic lupus erythematosus, Sjögren syndrome, ankylosing spondylitis, and BP.

Additionally, severe COVID-19 requiring intensive care unit admission was associated with a significantly increased risk for autoimmune diseases, including AA, psoriasis, BP, and sarcoidosis. By timeframe, risks for AA, AT, and psoriasis were significantly higher during the initial Delta-dominant period.

Vaccination Effect

Moreover, vaccinated individuals were less likely to develop AA, AT, psoriasis, Behçet disease, and various nondermatologic conditions than were those who were unvaccinated. This finding, wrote Heo and colleagues, “may provide evidence to support the hypothesis that COVID-19 vaccines can help prevent autoimmune diseases.”

“That’s the part we all need to take into our offices tomorrow,” said Brett King, MD, PhD, a Fairfield, Connecticut-based dermatologist in private practice. He was not involved with the study but was asked to comment.

Overall, King said, the study carries two main messages. “The first is that COVID-19 infection increases the likelihood of developing an autoimmune or autoinflammatory disease in a large population.” The second and very important message, he added, is that being vaccinated against COVID-19 provides protection against developing an autoimmune or autoinflammatory disease.

“My concern is that the popular media highlights the first part,” said King, “and everybody who develops alopecia areata, vitiligo, or sarcoidosis blames COVID-19. That’s not what this work says.”

The foregoing distinction is especially important during the fall and winter, he added, when people getting influenza vaccines are routinely offered COVID-19 vaccines. “Many patients have said, ‘I got the COVID vaccine and developed alopecia areata 6 months later.’ Nearly everybody who has developed a new or worsening health condition in the last almost 5 years has had the perfect fall guy — the COVID vaccine or infection.”

With virtually all patients asking if they should get an updated COVID-19 vaccine or booster, he added, many report having heard that such vaccines cause AA, vitiligo, or other diseases. “To anchor these conversations in real data and not just anecdotes from a blog or Facebook is very useful,” said King, “and now we have very good data saying that the COVID vaccine is protective against these disorders.”

George Han, MD, PhD, associate professor of dermatology at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell in Hempstead, New York, applauds investigators’ use of a large, robust database but suggests interpreting results cautiously. He was not involved with the study but was asked to comment.

“You could do a large, well-done study,” Han said, “but it could still not necessarily be generalizable. These autoimmune conditions they’re looking at have clear ethnic and racial biases.” Heo and colleagues acknowledged shortcomings including their study population’s monomorphic nature.

Additional issues that limit the study’s impact, said Han, include the difficulty of conceptualizing a 10%-20% increase in conditions that at baseline are rare. And many of the findings reflected natural patterns, he said. For instance, BP more commonly affects older people, COVID-19 notwithstanding.

Han said that for him, the study’s main value going forward is helping to explain a rash of worsening inflammatory skin disease that many dermatologists saw early in the pandemic. “We would regularly see patients who were well controlled with, for example, psoriasis or eczema. But after COVID-19 infection or a vaccine (usually mRNA-type), in some cases they would come in flaring badly.” This happened at least a dozen times during the first year of post-shutdown appointments, he said.

“We’ve seen patients who have flared multiple times — they get the booster, then flare again,” Han added. Similar patterns occurred with pyoderma gangrenosum and other inflammatory skin diseases, he said.

Given the modest effect sizes of the associations reported in the Korean study, Arkin and colleagues wrote in their JAMA Dermatology editorial that surveillance for autoimmune disease is probably not warranted without new examination findings or symptoms. “For certain,” King said, “we should not go hunting for things that aren’t obviously there.”

Rather, Arkin and colleagues wrote, the higher autoimmunity rates seen among the unvaccinated, as well as during the Delta phase (when patients were sicker and hospitalizations were more likely) and in patients requiring intensive care, suggest that “interventions that reduce disease severity could also potentially reduce long-term risk of subsequent autoimmune sequelae.”

Future research addressing whether people with preexisting autoimmune conditions are at greater risk for flares or developing new autoimmune diseases following COVID-19 infection “would help to frame an evidence-based approach for patients with autoimmune disorders who develop COVID-19 infection, including the role for antiviral treatments,” they added.

The study was supported by grants from the Research Program of the Korea Medical Institute, the Korea Health Industry Development Institute, and the National Research Foundation of Korea. Han and King reported no relevant financial relationships. Arkin disclosed receiving research grants to her institution from Amgen and Eli Lilly and Company, personal fees from Sanofi/Regeneron for consulting, and personal consulting fees from Merck outside the submitted work. Another author reported personal consulting fees from Dexcel Pharma and Honeydew outside the submitted work. No other disclosures were reported.

John Jesitus is a Denver-based freelance medical writer and editor.