Which condition is characterized by red patches on knuckles, rash on the chest, and proximal muscle weakness?

The condition characterized by red patches on the knuckles, a rash on the chest, and proximal muscle weakness is dermatomyositis. This autoimmune disorder affects both the skin and the muscles, leading to distinct and recognizable symptoms.

The red patches on the knuckles, known as Gottron's papules, are a classic manifestation of dermatomyositis. These papules are typically erythematous or violaceous and occur over the dorsal surfaces of the fingers. Additionally, the rash on the chest, often described as a heliotrope rash, appears as a violaceous or purplish discoloration and may be accompanied by eyelid edema.

Proximal muscle weakness is another hallmark of dermatomyositis. Patients often experience difficulty with activities that require the use of proximal muscles, such as lifting objects, climbing stairs, or raising their arms. This weakness is due to inflammatory damage to the muscle fibers, which can lead to progressive muscle degeneration if left untreated.

The combination of these skin rashes and muscle weakness uniquely points to dermatomyositis, making it the correct diagnosis in this scenario. While other conditions, such as lupus or rheumatoid arthritis, can also present with rashes and joint symptoms, they typically do not feature the specific