The triad of Raynaud’s phenomenon, fatigue and musculoskeletal pain belongs to quite common complaints among adolescents. Are these symptoms only nonspecific age-related variables or serious signs of any systemic autoimmune disorder? The authors of the study focus on differential diagnosis of primary (reversible symmetric vasospasm with no symptoms of systemic disease) and secondary Raynaud’s phenomenon (asymmteric structural vasculopathy as a sign of systemic disease). The second part of the study is dealing with mixed connective tissue disease (MCTD). The authors describe clinical course and diagnostic criteria of MCTD and prognosis of this rare entity on the basis of their own long-term followed cohort of patients.