Gottron's sign

Gottron's sign is a clinical dermatological manifestation primarily associated with Dermatomyositis, a type of inflammatory myopathy. It is characterized by the presence of flat-topped, violaceous papules and plaques over the extensor surfaces of joints, particularly the knuckles. This sign is considered pathognomonic for dermatomyositis, meaning it is specifically indicative of the disease and aids significantly in its diagnosis.

Presentation

Gottron's sign manifests as erythematous to violaceous, flat-topped papules and plaques. These lesions are typically found over the dorsal aspect of finger joints (metacarpophalangeal and interphalangeal joints), elbows, knees, and sometimes the toes. The skin changes may be accompanied by pruritus (itching) but are more often painless. Over time, these lesions can become hyperkeratotic, developing a scale or crust.

Pathophysiology

The exact pathophysiological mechanism behind Gottron's sign is not fully understood. However, it is believed to be related to the immune-mediated attack inherent in dermatomyositis, which targets both muscle and skin. The inflammation leads to vascular changes and subsequent dermal and epidermal damage, manifesting as the characteristic lesions of Gottron's sign.

Diagnosis

The presence of Gottron's sign is highly suggestive of dermatomyositis, especially when accompanied by other clinical features of the disease, such as muscle weakness, heliotrope rash (a purplish rash on the eyelids), and elevated muscle enzymes in the blood. A definitive diagnosis usually requires a combination of clinical presentation, laboratory tests (including muscle enzymes and specific autoantibodies), electromyography, and muscle biopsy.

Treatment

Treatment of Gottron's sign involves addressing the underlying dermatomyositis. This may include systemic corticosteroids, immunosuppressive agents, and antimalarial drugs for skin involvement. Topical therapies, such as corticosteroids and calcineurin inhibitors, may also be used to manage the skin lesions directly.

Prognosis

The prognosis for individuals with Gottron's sign, as part of dermatomyositis, varies. Early diagnosis and treatment can improve outcomes, but the disease can be chronic and relapsing. Complications of dermatomyositis, including lung involvement and increased cancer risk, can affect prognosis.

See Also

• Dermatomyositis
• Heliotrope rash
• Inflammatory myopathy
• Rash