Treatment of Juvenile Dermatomyositis in Children Under 18 Without Major Organ Involvement
Clinical Scenario
Age under 18 years
This protocol applies to paediatric patients with juvenile dermatomyositis aged under 18 who do not have major organ involvement and do not have extensive ulcerative skin disease. In this presentation, a structured induction approach is indicated from the outset.
Treatment Approach
The recommended induction regimen for this patient group centres on high-dose corticosteroid therapy combined with an additional disease-modifying agent. An alternative disease-modifying agent is used when patients do not tolerate the initial combination. The complete regimen — including sequencing, criteria for escalation, and monitoring requirements — is available in the full protocol.
Treatment Goals
Response is assessed at 12 weeks using objective measures:
- Improvement in Childhood Myositis Assessment Scale (CMAS) score
- Improvement in Manual Muscle Test 8 (MMT8) score
- Decrease in serum creatine phosphokinase (CPK)
- Decrease in physician global assessment of overall disease activity (PGA)
Clinically inactive disease requires meeting three out of four defined objective thresholds across these measures.
References
- For patients with severe disease (such as major organ involvement/extensive ulcerative skin disease), addition of intravenous cyclophosphamide should be considered.
- We recommend the induction regimen for treatment of new onset patients with JDM to be based on high dose of corticosteroids (oral or intravenous) combined with MTX.
- High-dose corticosteroids should be administered systemically either orally or intravenously in moderate–severe JDM.
- MTX should be started at a dose of 15–20 mg/m²/week (max absolute dose of 40 mg/week) preferably administered subcutaneously at disease onset.
- Addition of MTX or ciclosporin A leads to better disease control than prednisolone alone; safety profiles favour the combination of methotrexate and prednisolone.
- In patients who are intolerant to methotrexate, change to another DMARD, including ciclosporin A or MMF.
- If a newly diagnosed patient has inadequate response to treatment, intensification of treatment should be considered within the first 12 weeks, after consultation with an expert centre.
- In 2012, PRINTO published criteria defining clinically inactive disease; necessitating fulfilment of three out of four variables from CPK ≤150 U/L, CMAS ≥48, MMT8 ≥78 and PGA score of overall disease activity ≤0.2.
DOI: 10.1136/annrheumdis-2016-209247
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