Atypical juvenile dermatomyositis complicated by systemic capillary leak syndrome: case report and review of the literature

Early-onset juvenile dermatomyositis: A tertiary referral center experience and review of the literature

BACKGROUND/OBJECTIVES

The aim of our study is twofold: To evaluate the presentation, diagnosis, clinical course, and management of juvenile dermatomyositis (JDM) in children under three years of age, and to compare with older-onset patients.

METHODS

Nine patients with early-onset, and 63 patients with older-onset JDM followed between December 2010 and April 2022 are included. We also reviewed the literature on early-onset JDM from the inceptions of the PubMed/MEDLINE and Scopus databases up to April 1st, 2022.

RESULTS

Early-onset JDM patients were characterized by longer median diagnostic delay (p = 0.005), calcinosis (p = 0.006), anti-NXP2 antibody (p = 0.049). Diagnostic pathway included muscle biopsy (77.7% versus 50.8%). Muscle biopsy findings were more severe in the early-onset group (p<0.001). Although there was no difference in the partial and complete remission rates, the relapse rate was significantly higher in the early-onset group (p = 0.001), reflected to requirement of intravenous immunoglobulin (p = 0.001), cyclophosphamide (p = 0.011), and biological agents (p = 0.016). Literature search revealed 32 articles reporting 75 patients. The median diagnostic delay was 5 (1-30) months. Calcinosis was present in 29.5%. Twenty-three of the 44 patients (52.3%) had a muscle biopsy. Forty-one patients (64.1%) received second and third-line treatments. Complete remission was achieved in almost half of these patients (48.9%), but relapse was observed in 75%. The mortality rate was 10.2%.

CONCLUSION

Diagnosis can be challenging and delayed in early-onset JDM patients. Compared to older-onset JDM patients, this group had higher relapse rate, more severe muscle biopsy findings, and received intensive immunosuppressive treatment.

Angioedema-like presentation as the presenting finding of juvenile myositis and juvenile dermatomyositis in 2 patients

BACKGROUND

Juvenile dermatomyositis (JDM) is the most common subtype of idiopathic inflammatory myopathies in childhood. Gottron's papules, shawl sign, periorbital heliotrope rash, and periungual telengiectasis are characteristic skin findings of the disease. Besides characteristic skin involvement, some other skin findings, such as angioedema, may be seen prior or in the course of the disease. The presence of angioedema in JDM is emphasized in this report.

CASE PRESENTATIONS

We present 2 unrelated girls, aged 2 (case 1) and 12 years (case 2), who had developed symmetrical weakness in the proximal muscles, muscle pain, elevated muscle enzymes and angioedema. Both cases had abnormal muscle magnetic resonance imaging findings, suggestive of inflammatory myositis. Muscle biopsy was performed only in case 1, and major histocompatibility complex-1 expression on myofibers was shown consistent with JDM. Cases were diagnosed as probable and definite JDM, respectively. Angioedema was prominent, particularly in the lips and extremities of both cases, without laboratory evidence of C1 inhibitor deficiency or capillary leak syndrome, and absence of family history. Mast cell-mediated, acquired angioedema was the most likely diagnosis. In both cases, skin and muscle findings improved significantly with steroid treatment.

CONCLUSION

We suggest that angioedema may be among the characteristic skin findings in JDM, and may be included in subsequent definitions.