Viral infections may act as a trigger for fibromyalgia. Evidence suggests that certain viruses have a higher incidence of triggering a flare. Viruses associated with fibromyalgia may include:

For example, evidence notes there is a high rate of fibromyalgia among individuals with HIV and chronic HCV infections and .

There is also some suggestion that COVID-19 and long-COVID, which occur following infection with SARS-CoV-2, may have links to fibromyalgia and worsening of symptoms.

At present, researchers are still unsure of the exact cause of fibromyalgia. However, studies indicate that individuals with the condition may process pain differently.

Fibromyalgia flares describe when a person experiences a temporary increase in the number or intensity of symptoms. Flares typically occur after a trigger. This refers to an event that causes physical or emotional stress, such as an infection.

While the exact mechanism is still unclear, it is likely that stress on the body due to a viral infection may trigger a fibromyalgia flare.

For example, viral infections can increase cortisol production. Cortisol is known as the stress hormone, and the body produces it in response to perceived danger or a stressful situation. The hypothalamic-pituitary-adrenal (HPA) axis is a hormone system that controls the production and release of cortisol.

Evidence suggests that the stress response could lead to a dysfunction in the HPA axis, which may contribute to a flare of fibromyalgia. However, more research is still necessary to clearly understand the association between viral infections and fibromyalgia.

In addition to viral infection, research also highlights other potential triggers of the condition. These may include:

  • illness
  • injuries
  • surgery
  • certain health conditions
  • allergies
  • some medications
  • giving birth
  • mental illness
  • emotionally traumatic events
  • abuse