Approach to Elderly Man with Itchy Skin and Elevated CK

Immediate Diagnostic Workup

The American College of Cardiology recommends performing a complete rheumatologic and neurologic examination focusing on muscle strength and weakness, as muscle weakness is more typical of myositis than pain alone 1, 2
A thorough skin examination for dermatomyositis findings, including heliotrope rash, Gottron's papules, or V-sign/shawl sign, is necessary, as pruritus can precede visible skin changes 1, 2
Assessment for bulbar symptoms, dysphagia, or respiratory compromise is crucial, as these indicate severe myositis requiring immediate hospitalization 2, 3

The American College of Rheumatology recommends ordering CK, aldolase, AST, ALT, and LDH to quantify muscle inflammation 1
Troponin (preferably troponin I) should be evaluated for myocardial involvement, as myocarditis can be fatal 2, 3
ESR and CRP should be checked for inflammatory markers 1
An autoantibody panel, including myositis-specific antibodies, paraneoplastic antibodies, ANA, and anti-AChR antibodies, should be evaluated to assess for concomitant myasthenia gravis 2, 3

For CK ≥3x upper limit of normal with muscle weakness, the European League Against Rheumatism recommends initiating prednisone 0.5-1 mg/kg/day immediately 6, 2, 7
For CK ≥3x upper limit of normal with muscle weakness, referral to rheumatology or neurology is urgent 6, 2
Consider holding statins if the patient is taking them 2

The British Association of Dermatologists recommends beginning with emollients and mild topical steroids for at least 2 weeks 4, 5
Apply emollients with high lipid content liberally to the entire body surface 4, 5
Use 1% hydrocortisone cream to exclude asteatotic eczema 4, 5

The American Heart Association recommends immediate hospitalization and initiation of IV methylprednisolone 1-2 mg/kg if severe weakness, dysphagia, bulbar symptoms, respiratory compromise, rhabdomyolysis, or myocarditis are present 2, 3
Consider plasmapheresis for acute severe disease and IVIG therapy, though onset is slower 2, 3

The American College of Rheumatology recommends monitoring CK, ESR, and CRP regularly during treatment 1, 2
Taper corticosteroids slowly only when CK normalizes and clinical symptoms resolve 2
Consider steroid-sparing agents (methotrexate, azathioprine, mycophenolate mofetil) if no improvement after 4 weeks or for maintenance therapy 2, 3