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COVID-19 and myositis; true dermatomyositis or prolonged post viral myositis?

SARS-CoV-2 infection is best known for its respiratory symptoms, but this virus may cause many complications. One of them is connective tissue like diseases such as Juvenile Dermatomyositis (JDM) [1].

During the COVID-19 pandemic we noticed sudden spur of new cases of JDM hospitalized in our center as a tertiary hospital in Iran. From February 2020 to February 2021, eight new cases of JDM were admitted in Children’s Medical Center, Pediatrics Center of Excellence in Iran. During the same period in 5 years ago (2014 to 2019), just 2 to 4 new cases were admitted (Table 1). Mean of age of patients was higher with a high incidence in female during COVID-19 period.

Table 1 Comparison No cases of JDM during COVID-19 pandemic with last 5 years

A surge in the incidence of dermatomyositis has been reported during corona virus pandemic in Mumbai, that was limited to adult population [2]. We proposed three hypotheses to explain it.

The first hypothesis is to accept it as a true dermatomyositis. We know infectious agents can trigger dermatomyositis and JDM appears to have seasonal clustering. Infections with parvovirus B19, coxsackievirus B, enterovirus, influenza, group A streptococcus, and toxoplasma have all been documented in association with JDM. Some viruses play a greater role, perhaps SARS-CoV-2 may be a more potent trigger for this disorder.

Type 1 IFN pathway dysregulation has been implicated in the pathogenesis of JDM. Myxovirus resistance protein A is a type I interferon-inducible protein expressed in response to viral infection, it is also expressed in SARS-CoV-2 infection [3]. Deposition of Myxovirus resistance protein A in muscle fibers and capillaries is an early feature of dermatomyositis, occurring before characteristic perifascicular atrophy.

We assume that true dermatomyositis, triggered by SARS-CoV-2, may occur after this infection and its immunopathogenicity is via type 1 IFN pathway. Tanboon commented that 58-year-old COVID-19 patient reported to have myositis may actually have dermatomyositis [4].

The second hypothesis is to consider it as a prolonged post-viral myositis (PVM) that occurs following SARS-CoV-2 infection. Beydon reported MRI documentation of this type of myositis [5].

PVM typically presents with diffuse or multifocal muscle pain and/or rhabdomyolysis. Symptoms typically localize in the gastrocnemius and soleus muscles; however, other muscles may be involved. Symptoms usually begin about 3–7 days after the onset of fever and respiratory symptoms and then resolve within the first week but can persist up to 1 month [6]. Like other complications of COVID-19, this type of PVM may take longer time for remission.

Finally, it might be a Dermatomyositis-like syndrome, which mimics the symptoms of dermatomyositis but is not a real dermatomyositis. Now, we know some hyperinflammation syndromes as complications of COVID-19 infection. The most common of these syndromes is Multisystem Inflammatory Syndrome in Children, which is present as Kawasaki-like syndrome [7]. Dermatomyositis-like syndrome can be another presentation of hyperinflammation syndromes due to COVID-19. In these cases, if the duration of the disease and its complications are less than those we expect from a dermatomyositis, it can be named Dermatomyositis-like syndrome.

In future with follow up of these patients and more investigation, we can discuss better on this subject.

Availability of data and materials

All data generated or analysed during this study are included in this published article.



Juvenile Dermatomyositis


  1. Monti S, Balduzzi S, Delvino P, Bellis E, Quadrelli VS, Montecucco C. Clinical course of COVID-19 in a series of patients with chronic arthritis treated with immunosuppressive targeted therapies. Ann Rheum Dis. 2020;79(5):667–8.

    Article  CAS  PubMed  Google Scholar 

  2. Gokhale Y, Patankar A, Holla U, Shilke M, Kalekar L, Karnik ND, et al. Dermatomyositis during COVID-19 pandemic (a case series): is there a cause effect relationship? J Assoc Physicians India. 2020;68(11):20–4.

    PubMed  Google Scholar 

  3. Manzano GS, Woods JK, Amato AA. Covid-19-associated myopathy caused by type I interferonopathy. N Engl J Med. 2020;383(24):2389–90.

    Article  CAS  PubMed  Google Scholar 

  4. Tanboon J, Nishino I. COVID-19-associated myositis may be dermatomyositis. Muscle Nerve. 2021;63(1):E9–E10.

    Article  CAS  PubMed  Google Scholar 

  5. Beydon M, Chevalier K, Al Tabaa O, et al. Myositis as a manifestation of SARS-CoV-2. Ann Rheum Dis. 2021;80(3):e42.

    Article  CAS  Google Scholar 

  6. Agyeman P, Duppenthaler A, Heininger U, Aebi C. Influenza-associated myositis in children. Infection. 2004;32(4):199–203.

    Article  CAS  PubMed  Google Scholar 

  7. Mamishi S, Movahedi Z, Mohammadi M, Ziaee V, Khodabandeh M, Abdolsalehi MR, et al. Multisystem inflammatory syndrome associated with SARS-CoV-2 infection in 45 children: a first report from Iran. Epidemiol Infect. 2020;148:e196.

    Article  CAS  PubMed  Google Scholar 

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We are thank to Dr. F. Tahghighi, Dr. R. Assari, Dr. P. Sadeghi (staffs of pediatric Rheumatology division of Children’s Medical Center, Pediatrics Center of Excellence).




This work was not funded.

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The concept and case of need for the survey was led by V.Z. Data gathering and the first drafting was provided by N.M. All authors read and approved the final version of the manuscript.

Authors’ information

  1. 1.

    Paediatric Rheumatology Fellow, Children’s Medical Center, Pediatrics Center of Excellence, Tehran, Iran.

  2. 2.

    Professor of Pediatric Rheumatology, Department of Pediatrics, Tehran University of Medical Science, Tehran, Iran

Corresponding author

Correspondence to Vahid Ziaee.

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Movahedi, N., Ziaee, V. COVID-19 and myositis; true dermatomyositis or prolonged post viral myositis?. Pediatr Rheumatol 19, 86 (2021).

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