Mixed and undifferentiated autoimmune connective tissue diseases.

Dr Irwin M. Braverman has advanced our understanding of cutaneous manifestations of autoimmune connective tissue diseases (AI-CTD). Before the era of molecular diagnostics, Dr Braverman's careful clinical observations and detailed descriptions of patients with AI-CTD in his textbook Skin Signs of Systemic Disease provided insights into disease characterization, progression, and evolution. Patients from Dr Braverman's career who did not fulfill criteria for a single clinical entity but rather were diagnosed with undifferentiated connective tissue disease or mixed connective tissue disease are discussed. In addition, key observations of Dr Braverman into the cutaneous manifestations of Sjögren syndrome and the systemic complications of urticarial vasculitis are highlighted.