Dermatomyositis Multimedia

Station Instructions: Assess this patient presenting with a rash and weight loss.

1. Key History‑Taking Points

History of Presenting Complaint:

Muscle Symptoms

• Weakness: Onset, duration, and pattern (symmetrical proximal limb weakness — difficulty climbing stairs, combing hair, rising from chair).

• Pain: Myalgia or tenderness?

• Fatigue: Associated with exertion?

• Progression: Rate of worsening, any swallowing or breathing difficulty (bulbar or respiratory involvement).

Skin Symptoms

• Rash:

  • Heliotrope rash (violaceous periorbital discolouration, eyelid oedema)

  • Gottron’s papules (scaly papules over MCP, PIP joints)

  • Shawl sign (photosensitive rash over shoulders, neck, upper chest)

  • V-sign (anterior chest rash)

  • Mechanic’s hands (hyperkeratotic fissuring on lateral fingers)

• Photosensitivity

• Nail Changes: periungual erythema (redness), ragged cuticles, longitudinal ridging, dilated nailfold capillaries and splinter haemorrhages

Systemic Symptoms

• Respiratory: Cough, breathlessness (interstitial lung disease)

• Dysphagia / dysphonia: Oesophageal or pharyngeal weakness

• Constitutional: Weight loss, fever, fatigue

• Arthralgia: Overlap with other connective tissue diseases

Malignancy Screening History (age and gender-specific malignancy screening)

• Weight loss, night sweats, postmenopausal bleeding, haematuria, cough, breast changes, bowel symptoms

• Previous malignancy, family history of cancer

Past Medical & Family History

• Other autoimmune diseases (SLE, scleroderma, RA, thyroid disease)

• Family history of myositis or connective tissue disease

Drug & Exposure History

• Drugs: statins, hydroxyurea, penicillamine

• UV exposure, recent infection, or vaccination

Functional Impact

• Difficulty performing daily tasks, occupation impact, fatigue, emotional wellbeing

2. Key Examination Findings

• General Inspection:

  • Periorbital violaceous rash (heliotrope rash)

  • Gottron’s papules over MCP joints, knees or elbows

  • Shawl or V-sign rash on chest and upper back

  • Mechanic’s hands (rough, fissured skin on fingers)

  • Raynaud’s phenomenon 

  • Nail changes: Periungual erythema, dilated capillaries, ragged cuticles, longitudinal ridging, splinter haemorrhages

  Muscle Examination:

  • Symmetrical proximal muscle weakness (shoulder and hip girdle)

  • Muscle tenderness, wasting (late stage)

  • Assess tone, reflexes (usually normal)

  • Test bulbar and neck flexor strength

  Systemic Examination:

  • Respiratory: fine bibasal end-inspiratory crackles (ILD)

  • Cardiovascular: arrhythmias, cardiomyopathy

  • Abdominal: organomegaly or masses (malignancy)

3. Specific Investigations

Blood Tests:

• ↑ Muscle enzymes: CK, aldolase, AST, ALT, LDH

• Autoantibodies:

  • Myositis-specific: anti-Mi-2, anti-MDA5, anti-TIF1-γ, anti-NXP2

  • Myositis-associated: anti-Jo-1, anti-PL-7, anti-PL-12 (antisynthetase syndrome)

  • ANA, ENA screen

• FBC, U&E, ESR, CRP

Imaging & Functional Tests:

• MRI of muscles: oedema and inflammation

• EMG: myopathic pattern (short, low-amplitude potentials)

• Muscle biopsy: perivascular and perifascicular inflammation, fibre necrosis (diagnostic)

Malignancy Screening:

• Age and gender-appropriate screening (urinalysis, PSA, mammogram, pelvic/trasnvaginal ultrasound, colonoscopy, CT chest/abdomen/pelvis)

• PET-CT if paraneoplastic suspicion

Other Tests:

• Pulmonary function tests ± HRCT for interstitial lung disease

• Echocardiogram if cardiac involvement suspected

• Capillaroscopy of nailfoldes (dilated capillaries)

• Skin biopsy (interface dermatitis)

• SLE
• Scleroderma
• Sjogren’s Syndrome
• Inflammatory Myopathis (Polymyositis, drug-induced myopathies)

5. Management

Multidisciplinary Approach:
Dermatology, Rheumatology, Neurology, Oncology, Respiratory, Physiotherapy

General Measures

• Rest during acute phase, then graded physiotherapy
• Sun protection and topical emollients for rash

• Psychological and occupational support

Pharmacological Treatment

• Corticosteroids: Oral prednisolone (1 mg/kg/day), slow taper
• Steroid-sparing agents: Methotrexate, azathioprine, mycophenolate, or cyclophosphamide (if resistant)
• IV immunoglobulin (IVIG): for refractory or severe disease (esp. dysphagia)
• Biologics: Rituximab or JAK inhibitors in resistant cases

• Topical agents: Topical steroids or calcineurin inhibitors for cutaneous lesions

Malignancy Surveillance

• Age and gender-appropriate malignancy screening at baseline screening and annual review for 3–5 years

Interstitial Lung Disease

• Immunosuppression and pulmonary monitoring

Supportive

• Dietitian (if dysphagia), physiotherapy, speech and language therapy

 Dermatomyositis Cheat Sheet