Panniculitis in a patient with dermatomyositis

Subcutaneous tissue involvement in idiopathic inflammatory myopathies: Systematic literature review including three new cases and hypothetical mechanisms

INTRODUCTION

Involvement of subcutaneous tissue in idiopathic inflammatory myopathies (IIM) is poorly known.

METHODS

We conducted a systematic review of the literature regarding panniculitis and lipodystrophy/lipoatrophy in juvenile and adult IIM via PubMed/Medline, Embase and Scopus databases. Three local observations are included in this review. Epidemiological, clinical, paraclinical and therapeutic data were collected.

RESULTS

Panniculitis appears to be more common in adults than in juveniles. It was mainly localised in the upper and lower limbs. Panniculitis improved in most cases with steroids and panniculitis and myositis had a similar course in 83.3% and 72.2% of cases in juveniles and adults, respectively. Lipodystrophy appeared to be more frequent in juveniles and was only observed in dermatomyositis in both juveniles and adults. Lipodystrophy was mainly partial in juveniles and adults. The median time from myositis to the diagnosis of lipodystrophy was 6 years [0-35] and 2.5 years [0-10] in juveniles and adults, respectively. Lipodystrophy was associated with anti-TIF1 gamma auto-antibody positivity, a polycyclic/chronic course of myositis and the occurrence of calcinosis and might be an indicator of poor disease control.

CONCLUSION

Adipose tissue involvement, particularly lipodystrophy, occurs almost exclusively in dermatomyositis. The insidious onset and lack of awareness of the diagnosis may underestimate its prevalence. Larger studies are needed to identify possible risk factors in these patients, to better potential underlying pathophysiological process, in order to discuss potential therapeutic targets.

Anti-MDA5 Antibody-Positive Dermatomyositis Presenting with Cellulitis-Like Erythema on the Mandible as an Initial Symptom

Panniculitis is an uncommon skin eruption observed in patients with dermatomyositis (DM)/clinically amyopathic dermatomyositis (CADM), especially in anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive DM. We present here a 51-year-old Japanese woman with an anti-MDA5 antibody-positive DM who initially had cellulitis-like erythema on her right mandible. Histopathological findings showed a subcutaneous lobular infiltration of lymphocytes. The patient developed typical skin eruptions of DM/CADM, rapidly progressive interstitial lung disease, and severe muscle weakness 2 weeks after the first visit. After the diagnosis of anti-MDA5 antibody-positive DM, she was treated with intravenous steroid pulse therapy (methylprednisolone, 1,000 mg/day for 3 days), oral prednisolone at 1.0 mg/kg/day, and tacrolimus at 4.0 mg/day. The lesions of panniculitis associated with DM/CADM typically present on the buttocks, thighs, arms, and abdomen. This is the first DM/CADM case with localized panniculitis on the face. Panniculitis and myositis usually show simultaneous improvement during treatment. Although panniculitis disappeared with steroid and tacrolimus treatment and did not recur, muscle weakness was intractable and recurred in this case. This indicates that the clinical courses of panniculitis and myositis of DM/CADM do not always change in parallel.

Panniculitis associated with amyopathic dermatomyositis

Panniculitis is a rare clinical finding in dermatomyositis, with less than 30 cases reported and there is only one case associated with the amyopathic subtype described in the literature. The present report describes a 49-year-old female patient that one year after being diagnosed with amyopathic dermatomyositis, presented indurated, painful, erythematous to violaceous nodules located on the upper limbs, thighs and gluteal region. Skin biopsy revealed lobular panniculitis with a lymphocytic infiltrate. The patient was treated with prednisone and methotrexate, but remained unresponsive to treatment.

Update on management of connective tissue panniculitides

In connective tissue diseases, panniculitis can be the sole manifestation or can occur along with the underlying disease process. The best described forms of connective tissue panniculitis are lupus erythematosus panniculitis and lupus profundus, panniculitis associated with dermatomyositis, and morphea- and scleroderma-associated panniculitis. These processes cause significant morbidity, such as deep atrophic scars, cosmetic disfigurement, and psychiatric sequelae. Because the inflammation is located in the subcutaneous adipose layer, topical therapies may not penetrate enough to be effective, and systemic agents are required. Despite the large number of reported cases and therapies, recommendations for treatment are based largely on case series and expert opinion due to a lack of controlled therapeutic trials. All treatments are off-label in the United States. The lack of validated clinical outcome measures makes systematic and controlled studies difficult. Nonetheless, further investigation into the most effective therapies for these conditions is needed.