Table 4 Therapies used in juvenile dermatomyositis

Supportive therapy

Early and intensive physical therapy is essential in order to avoid contractures and improve/maintain muscle strength, even during active myositis. Participation in sports is desirable after individual counseling. Effective sun protection is essential, incl. textile protection and sunscreen.

The following treatments may be considered individually:

• Supplementation of vitamin D, e.g. depending on 25-OH vitamin D level, glucocorticoid treatment and/or bone mineral density

• Supplementation of calcium, e.g. in case of insufficient intake

• Hydroxychloroquin

Initial glucocorticoid therapy

The principal glucocorticoid strategy options include

• Intermittent intravenous methylprednisolone pulse (IVMP) therapy + moderate-to-high-dose daily glucocorticoids (prednisone equivalent 0.5–2 mg/kg [max. 80 mg] daily)

• Intermittent IVMP therapy + lower-to-moderate dose daily glucocorticoids (prednisone equivalent 0.2–0.5 mg/kg daily)

• High-dose daily glucocorticoid therapy (2 mg/kg [max. 60–80 mg] daily) +/− initial single IVMP pulse

Glucocorticoid tapering

The following landmarks may be applied when tapering glucocorticoids, assuming an adequate treatment response (i.e. treatment targets are reached):

• IVMP

 o 20–30 mg/kg (max. 1000 mg) daily × 3 days

 o At 2 and 4 weeks, subsequently every 4–6 weeks × 6–12 months

• High-dose daily glucocorticoids (prednisone or prednisolone)

 o 2 mg/kg (max. 60–80 mg) × 1 month, then start taper

 o 50% of initial dose at 2 months, 25% at 4 months, 12.5% at 6 months, discontinue at 12 months

• Moderate-dose daily glucocorticoids (0.5–2 mg/kg daily, < 60 mg daily)

 o Stop within 12 months

• Lower-dose daily glucocorticoids (< 0.5 mg/kg daily)

 o Stop within 12 months

Glucocorticoid-sparing therapies

The following glucocorticoid-sparing therapies are used in the initial treatment:

• Methotrexate (MTX) 15–20 mg/m² (max. 30 mg) once weekly (s.c. preferred)

• MTX 15–20 mg/m² (max. 30 mg) once weekly (s.c. preferred) + intravenous immune globulins (IVIG) (especially in case of severe juvenile dermatomyositis)

In case of MTX intolerance, MTX can be replaced by azathioprin (AZA), cyclosporin A (CSA) or mycophenolate mofetil (MMF).

Refractory disease

In case of not reaching predefined targets (Table 3) or disease flare, a change in therapy is required. In this situation, current therapies should be intensified, exchanged and/or another therapy added.

Further treatment should be discussed individually with experts. The following agents are generally used:

AZA, calcineurin inhibitors, cyclophosphamide, IVIG, MMFmycophenolate mofetil, rituximab, tumor necrosis factor inhibitors