From the Guidelines
Anti-DM5 (Dermyositis-specific autoantibody 5)-associated idiopathic inflammatory myopathy is characterized by aggressive interstitial lung disease (ILD), particularly in Asian patients, and is associated with a distinct set of clinical features, including skin and systemic manifestations. The clinical features of Anti-DM5-associated idiopathic inflammatory myopathy include skin manifestations such as photosensitive rash, and systemic features like arthralgia, Raynaud's phenomenon, and dysphagia due to pharyngeal muscle involvement 1.
Key Clinical Features
- Aggressive ILD, which can be rapidly progressive and life-threatening
- Skin manifestations, including photosensitive rash
- Systemic features, such as arthralgia, Raynaud's phenomenon, and dysphagia
- Cardiac involvement, including arrhythmias or myocarditis
- Constitutional symptoms, like fever, fatigue, and weight loss
Management
Early recognition of these clinical features is crucial for prompt initiation of immunosuppressive therapy, typically starting with high-dose corticosteroids and often requiring additional agents like methotrexate, azathioprine, or mycophenolate mofetil for long-term management 1. Some key points to consider in management include:
- High-dose corticosteroids should be administered systemically, either orally or intravenously, in moderate to severe cases
- Methotrexate (MTX) should be started at a dose of 15-20 mg/m2/week, preferably administered subcutaneously, at disease onset
- Intravenous immunoglobulin may be a useful adjunct for resistant disease, particularly when skin features are prominent
- Mycophenolate mofetil (MMF) may be a useful therapy for muscle and skin disease, including calcinosis It is essential to note that the presence of anti-DM5 antibodies is associated with a higher risk of malignancy, particularly in older patients, necessitating thorough cancer screening 1.
From the Research
Clinical Features of Anti-DM5-associated Idiopathic Inflammatory Myopathy
The clinical features of Anti-DM5 (Dermyositis-specific autoantibody 5)-associated idiopathic inflammatory myopathy include:
- Skin manifestations such as Gottron's sign, heliotrope rash, mechanic's hand, and skin ulcers 2, 3, 4
- Systemic manifestations including interstitial lung disease (ILD), arthritis, and cardiac involvement 5, 4, 6
- Muscle weakness and inflammatory myopathy on biopsy 3, 4
- Normal or elevated creatine kinase levels 3, 4
Skin Manifestations
The skin manifestations of Anti-DM5-associated idiopathic inflammatory myopathy are:
- Gottron's sign: a characteristic skin lesion found on the hands and feet 2, 3, 4
- Heliotrope rash: a purple rash found on the face and arms 2, 3, 4
- Mechanic's hand: a skin lesion found on the hands, characterized by thickening and cracking of the skin 2
- Skin ulcers: found in some patients with Anti-DM5-associated idiopathic inflammatory myopathy 2
Systemic Manifestations
The systemic manifestations of Anti-DM5-associated idiopathic inflammatory myopathy include:
- Interstitial lung disease (ILD): found in some patients with Anti-DM5-associated idiopathic inflammatory myopathy 5, 4
- Arthritis: found in some patients with Anti-DM5-associated idiopathic inflammatory myopathy 4, 6
- Cardiac involvement: including second-degree heart block, found in some patients with Anti-DM5-associated idiopathic inflammatory myopathy 6
Treatment and Outcome
The treatment and outcome of Anti-DM5-associated idiopathic inflammatory myopathy include: