What is Gottron Sign?
Gottron sign is erythematous to violaceous macules (flat, non-palpable patches) over the extensor surfaces of joints, particularly the knuckles, elbows, knees, malleoli, and toes, representing a pathognomonic cutaneous manifestation of dermatomyositis. 1
Clinical Definition and Characteristics
Gottron sign differs from Gottron papules in that it consists of flat, non-raised macules rather than palpable papules over the same anatomic locations—the extensor surfaces of joints. 1 The lesions display a characteristic violaceous or erythematous discoloration and are not scaly or elevated. 1
Anatomic Distribution
The sign typically appears over:
- Finger joints (metacarpophalangeal and interphalangeal joints) 1
- Elbows 1
- Knees 1
- Malleoli (ankle bones) 1
- Toes 1
Diagnostic Significance
Gottron sign is considered pathognomonic (uniquely characteristic) for dermatomyositis and carries substantial diagnostic weight in classification criteria. 1 In the 2017 EULAR/ACR classification criteria for idiopathic inflammatory myopathies, Gottron sign receives a score of 3.3 points without muscle biopsy and 3.7 points with muscle biopsy—among the highest weighted variables in the entire classification system. 1
Patients with pathognomonic skin rashes including Gottron sign can be accurately classified as having dermatomyositis without requiring muscle biopsy data. 1
Distinction from Gottron Papules
While related, these are distinct entities:
- Gottron papules: Erythematous to violaceous papules (raised, palpable lesions) over extensor joint surfaces, sometimes scaly 1
- Gottron sign: Erythematous to violaceous macules (flat, non-palpable patches) over the same locations 1
Both are highly specific for dermatomyositis, though Gottron sign carries slightly more diagnostic weight in classification criteria. 1
Clinical Context and Associated Features
Gottron sign typically appears alongside other dermatomyositis manifestations including:
- Heliotrope rash (periorbital violaceous discoloration) 1, 2
- Shawl sign (erythema over shoulders and upper back) 1, 2
- V-sign (erythema over anterior chest) 2
- Periungual telangiectasias 2
- Mechanic's hands (hyperkeratotic, cracked skin on palms and fingers) 2
Prognostic Implications
Ulcerative Gottron sign (when ulceration develops within these lesions) represents a high-risk clinical feature strongly associated with rapidly progressive interstitial lung disease, particularly in patients with anti-MDA5 antibodies. 3 Patients with ulcerative Gottron sign demonstrate:
- Significantly higher rates of acute/subacute interstitial pneumonia (73% vs 3%, p<0.001) 3
- Lower baseline creatine kinase levels 3
- Higher serum ferritin levels 3
- Significantly worse survival outcomes 3
Clinical Assessment Utility
Gottron sign serves as an "activity lesion" in validated dermatomyositis assessment tools like the Cutaneous Assessment Tool, helping clinicians track disease activity and treatment response. 1 The presence of this sign indicates active cutaneous disease that can improve with appropriate immunosuppressive therapy. 1