Key takeaways:

• Nearly 5% of people with classic dermatomyositis were also diagnosed with postural orthostatic tachycardia syndrome.
• Although experts acknowledged the association, the reason for the link remains unclear.

People with dermatomyositis displayed a greater prevalence of concurrent postural orthostatic tachycardia syndrome compared with those who had other autoimmune conditions, according to a research letter published in JAMA.

“We have seen enough people with this association that we believe it is worth noting,” Victoria Werth, MD, MS, professor of dermatology at the Perelman School of Medicine at the University of Pennsylvania, told Healio.

Data derived from Jun S, et al. JAMA Dermatol. 2026;doi:10.1001/jamadermatol.2026.2132.

It is estimated that postural orthostatic tachycardia syndrome (POTS), an autonomic disorder characterized by a rapidly increased heart rate after standing, affects 0.1% to 1% of Americans. However, nearly 5% of people with classic dermatomyositis were also diagnosed with POTS, Werth and colleagues wrote.

Dermatomyositis is an autoimmune disease characterized by muscle weakness, dermatologic features and autoantibody involvement, according to the study. To evaluate the prevalence of POTS diagnoses among people with dermatomyositis, researchers compared the number of POTS cases found in the University of Pennsylvania’s dermatomyositis database with the number of cases in the cutaneous lupus erythematosus database.

Of the patients with dermatomyositis, 84.7% were women, 87.5% were white and the median age of disease onset was 49.29 years. More than half (54.1%) of patients had classic dermatomyositis whereas the remaining had clinically amyopathic dermatomyositis.

Results showed that of 608 people with dermatomyositis, 18 also had POTS. When split by subtype, 4.9% of those with classic dermatomyositis vs. 0.7% of those with clinically amyopathic dermatomyositis had POTS. Classic dermatomyositis was significantly represented in patients with dermatomyositis and POTS vs. dermatomyositis without POTS (88.9% vs. 53.1%; P = .003), the authors reported.

In contrast, POTS affected 0.6% with cutaneous and systemic lupus and none with cutaneous lupus only. Each POTS diagnosis occurred at a median of 5.03 years after dermatomyositis onset.

“Typically, we see dermatomyositis first and then POTS later,” Werth said. “While we do not understand the pathogenesis of POTS very well, knowing there is an association with dermatomyositis could help begin to put things together.”

According to Werth, one hypothesis for the association involves the COVID-19 pandemic. As Healio previously reported, the incidence rate of POTS increased from 1.42 per 1,000,000 person-years pre-pandemic to 20.3 per 1,000,000 person-years post-pandemic. A similar trend was seen with dermatomyositis as well, according to Werth.

“We know COVID can also flare dermatomyositis and potentially induce it, so is there an association there? We do not know and it is hard to prove,” Werth told Healio. “Nevertheless, there is a significant link between POTS and dermatomyositis.”

Though the researchers did not consider it to be statistically significant, they found that 55.6% of the patients with POTS vs. 38.1% without POTS in this study had a positive antinuclear antibodies result. However, they did not find an association with myositis-specific autoantibodies.

“Although no myositis-specific autoantibody was associated with POTS, broad immune overactivation in dermatomyositis may precede the development of functional autoantibodies targeting autonomic receptors previously reported in POTS,” Werth and colleagues wrote. “Moreover, while both dermatomyositis and cutaneous lupus are characterized by type 1 interferon signatures, POTS may share inflammatory pathways specific to dermatomyositis, such as interferon–beta-mediated responses. Enrichment of POTS in classic dermatomyositis also suggests subtype differences within dermatomyositis. Further studies are needed to clarify the autoimmune mechanisms linking dermatomyositis and POTS.”

For more information:

Victoria Werth, MD, MS, can be reached at werth@pennmedicine.upenn.edu.