Connective Tissue Diseases in the Skin: Emerging Concepts and Updates on Molecular and Immune Drivers of Disease.

Cutaneous manifestations are common across the spectrum of autoimmune diseases. Connective tissue diseases manifesting in the skin are often difficult to classify and require integration of clinical, histopathologic, and serologic findings. This review focuses on the current understanding of the molecular and immune drivers involved in the pathogenesis of cutaneous lupus erythematosus, dermatomyositis, scleroderma/systemic sclerosis, and mixed connective tissue disease. Recent research advances have led to the emergence of new ancillary tools and useful diagnostic clues of which dermatopathologists should be aware to improve diagnostic accuracy for these diseases.