Episodes are typically triggered by cold or emotional stress. Primary Raynaud's, also known as idiopathic, means that it is spontaneous, of unknown cause and unrelated to another disease. Secondary Raynaud's occurs as a result of another condition, has an older age at onset, episodes are intensely painful, can be asymmetric, and associated with skin lesions. Secondary Raynaud's can occur due to a connective-tissue disorder, such as scleroderma or lupus, injuries to the hands, prolonged vibration, smoking, thyroid problems, and certain medications, such as birth control pills. Diagnosis is typically based on the symptoms.