The cases of 16 patients with childhood polymyositis or dermatomyositis have been followed up for 6 to 16 years. The cases of 10 patients, who were initially treated with corticosteroids in high dosage and maintained with a low dosage for an average of 2.5 years, were followed up for a mean period of 8.3 years. The seven patients who were treated within one to six months after onset of symptoms had a short period of severe disability; six made an excellent recovery, and one died from common iliac artery thrombosis. Three patients treated 17 to 36 months after onset of symptoms made a less complete, but functionally satisfactory recovery. Six patients were not treated with steroids and were followed up for 13 years. They had a much longer period of severe disability but they also made a good recovery eventually. The incidence of calcinosis was 50% in both the treated and untreated patients.
Rose AL. Childhood PolymyositisA Follow-Up Study With Special Reference to Treatment With Corticosteroids. Am J Dis Child. 1974;127(4):518–522. doi:10.1001/archpedi.1974.02110230064009