Treatment of Juvenile Dermatomyositis

Initial Treatment Approach

The American College of Rheumatology recommends starting treatment immediately after diagnosis with high-dose corticosteroids (preferably methylprednisolone 15-30 mg/kg/dose for 3 consecutive days) followed by oral prednisolone 1-2 mg/kg/day, always in combination with methotrexate 15-20 mg/m² weekly, preferably subcutaneously 1, 2
Methotrexate should be administered at 15-20 mg/m² weekly, preferably subcutaneously for better absorption compared to oral administration, as recommended by the European League Against Rheumatism 1, 2, 4
Essential supportive measures include rigorous photoprotection, calcium and vitamin D supplementation, and supervised physiotherapy, as suggested by the American Academy of Pediatrics 1, 4

At 12-week evaluation, if clinical improvement is observed, continue methotrexate and start gradual steroid tapering, as recommended by the American College of Rheumatology 1, 5
In case of no improvement, verify adherence and tolerance to treatment before intensifying therapy, as suggested by the European League Against Rheumatism 1, 5

Indicators of severe disease include major organ involvement, dysphagia, extensive cutaneous vasculitis, or ulcerative cutaneous disease, as defined by the American College of Rheumatology 1, 5
Treatment intensification options include:

If the patient does not tolerate methotrexate, switch to alternative drugs, such as mycophenolate mofetil (MMF) or cyclosporine A, as recommended by the European League Against Rheumatism 5, 4, 3

Regular evaluations should include muscle strength (using validated scales like CMAS or MMT8), cutaneous disease (using tools like CAT), and major organ involvement, as suggested by the American Academy of Pediatrics 1, 2, 3
Persistent cutaneous disease reflects active systemic disease and should be treated by intensifying systemic immunosuppression, not just topical therapies, as recommended by the American College of Rheumatology 4

Steroid reduction: start gradual tapering when clinical improvement is observed, as recommended by the European League Against Rheumatism 1, 4
Methotrexate suspension: consider only when the patient has been in remission for at least 1 year without steroids, as suggested by the American College of Rheumatology 1, 2

Cutaneous calcinosis: higher risk in children, particularly associated with anti-p140 (NXP-2) antibodies, as reported by the American Academy of Pediatrics 5
Gastrointestinal vasculopathy: potentially severe complication requiring close monitoring, as recommended by the European League Against Rheumatism 3

Do not delay intensification: if no adequate response is observed within 12 weeks, intensify treatment after consultation with an expert center, as suggested by the American College of Rheumatology 4
Do not underestimate cutaneous disease: persistent cutaneous disease indicates active systemic disease and requires intensification of systemic immunosuppression, as recommended by the European League Against Rheumatism 4
Always verify adherence: before intensifying therapy for apparent refractoriness, verify adherence and tolerance to treatment, as suggested by the American Academy of Pediatrics 1, 5