Which disease presents with hand weakness and skin discoloration in an adult?

Dermatomyositis is the Primary Disease Causing Hand Weakness and Skin Discoloration in Adults

Dermatomyositis presents with the classic combination of proximal muscle weakness (including hands) and characteristic skin discoloration, making it the most likely diagnosis when both features are present together. 1

Characteristic Skin Manifestations

The skin changes in dermatomyositis are highly distinctive and include:

• Gottron papules: Erythematous papules over the knuckles and finger joints 1
• Heliotrope rash: Violaceous discoloration around the eyelids with periorbital edema 1
• Erythematous, photosensitive rash with poikiloderma (mixed hyperpigmentation and hypopigmentation) affecting the face, neck, torso, fingers, and extensor surfaces of extremities 1
• Periungual telangiectasias: Dilated capillaries around the nail beds 1

The rash typically involves the hands prominently, with salmon-pink to violaceous discoloration that may be accompanied by the characteristic Gottron papules over the finger joints. 1

Muscle Weakness Pattern

Symmetric proximal muscle weakness develops over weeks to months, affecting the shoulders, hips, and proximal limb muscles, which includes weakness in hand grip and finger flexion. 1 The weakness is progressive and coupled with elevated muscle enzyme levels (creatine kinase). 1

Diagnostic Approach

The Mayo Clinic Proceedings guidelines recommend using the Bohan and Peter criteria, requiring 4 of 5 features for definite diagnosis: 1

1. Characteristic skin findings (Gottron papules, heliotrope rash, photosensitive eruption)
2. Proximal muscle weakness
3. Elevated muscle enzyme levels (CK, aldolase, LDH)
4. Myopathic pattern on electromyography (polyphasic motor unit potentials, fibrillation potentials)
5. Endomysial mononuclear inflammatory infiltrate on muscle biopsy

Magnetic resonance imaging (T2-weighted with fat suppression and STIR sequences) provides useful information to identify muscle inflammation and guide biopsy site selection. 1

Important Differential Consideration

While systemic sclerosis (scleroderma) can cause hand involvement with skin changes, the skin manifestations are fundamentally different:

• Scleroderma causes skin thickening and tightening (sclerodactyly), not the inflammatory rash seen in dermatomyositis 2, 3
• Scleroderma presents with Raynaud phenomenon, digital ulcers, and calcinosis rather than Gottron papules 1, 4
• The skin changes in scleroderma are fibrotic rather than inflammatory 5, 4

Critical Pitfalls to Avoid

Do not delay workup for malignancy, as dermatomyositis in adults has a significant association with underlying cancer, particularly in patients over age 40. 1 Screen for occult malignancy with age-appropriate cancer screening including CT chest/abdomen/pelvis, mammography, and colonoscopy.

Assess for interstitial lung disease early, as pulmonary involvement ranges from aspiration pneumonia to progressive interstitial lung disease and significantly impacts mortality. 1 Obtain baseline pulmonary function tests and high-resolution CT chest.

Screen for cardiac involvement with electrocardiography and echocardiography, as asymptomatic arrhythmias and diastolic dysfunction can occur even without overt symptoms. 1

Treatment Recommendations

For adult patients with idiopathic inflammatory myositis, initiate high-dose corticosteroids (prednisone 1 mg/kg/day) concurrent with a steroid-sparing agent such as methotrexate (15-25 mg weekly), azathioprine (2 mg/kg/day), or mycophenolate mofetil (2-3 g/day), followed by a tapering course of corticosteroids over months. 1

For severe disease with extensive organ involvement or refractory disease, escalate to high-dose methylprednisolone plus intravenous immunoglobulin (2 g/kg divided over 2-5 days), cyclophosphamide, rituximab, or cyclosporine. 1