From the open-ended exposure question, stressful life events constituted 11% of the reported exposures. Patients >7.5 years of age reportedly experienced a stressful life event more frequently in the 6 months before diagnosis than younger patients (P = 0.003; OR 3.5; 95% CI 1.5, 7.9). Unusual sun exposures comprised 7% of the total exposures in the 6 months before diagnosis and occurred exclusively in patients with JDM, not JPM. Unusual sun exposures included those resulting in sunburn, as well as receiving more sun than usual or travel to a more sunny location. An unusual chemical exposure was recorded 3% of the time and included application of pesticides inside or around the home, painting the home, use of formaldehyde to clean the child's bed and application of a hair perming chemical. Seven (2%) reported exposures involving unusual animal contact within 6 months of illness onset, including a dog or cat scratch, exotic bird bite or multiple flea or mosquito bites. Four (2%) exposures involved weight-training exercise or physical trauma, and two (0.6%) exposures involved dietary supplement usage before illness onset, including creatine monokinase and Echinacea. These less-frequent exposures were present exclusively in patients with JDM, except that weight-training exercise was also noted in one JPM patient. Weight training, physical trauma and dietary supplements were seen exclusively in patients >7.5 years of age at diagnosis and in patients with a greater delay to diagnosis.