Macrophage Activation Syndrome (MAS)

Macrophage Activation Syndrome is triggered by an underlying health issue, such as an autoimmune or autoinflammatory disease. It often occurs in those who's underlying disease is newly diagnosed or very active, but can also happen with some infections even if the disease is well managed.


What causes MAS?

  • Triggered by an autoimmune or autoinflammatory disease.
  • Seen most in patients with Still's Disease, including sJIA, and Lupus, but it can happen in other autoimmune and autoinflammatory diseases.
  • Mostly occurs in those with active disease (flaring) or undiagnosed
  • Infections are also a common trigger

Patient-led education on Macrophage Activation Syndrome was made possible by the financial support of Sobi.

Click to see other Still's Disease brochures

Patient Guide

Download Patient Guide

FREE e-Book written by patients for patients (and medically approved by professionals)

Folleto para profesionales de la salud

Download Brochure

Imprima este folleto (o comparta esta página web) y entrégueselo a sus profesionales de la salud.

Check out these stories from Katelyn and Jenny, 2 patients who have experienced and recovered from MAS.

Katelyn's MAS Story

What Surprised Katelyn About MAS

What Katelyn Wants Patients to Know About MAS

Jenny's MAS Story

What Surprised Jenny About MAS

What Jenny Wants Patients to Know About MAS

MAS Educational Social Media Posts

Understanding MAS

  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón

Warning Signs of MAS

  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón

Diagnosing MAS



  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón

Treating MAS



  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón
  • Título de la diapositiva

    Write your caption here
    Botón

Other MAS Resources

Consulta estos excelentes recursos para obtener más información sobre el síndrome de activación macrofágica.