Pallor of extremities, followed by pain and cyanosis suggests a diagnosis of Raynaud&;s phenomenon. Raynaud's as the presenting manifestation is most strongly associated with scleroderma.Raynaud's is associated with viually every patient of scleroderma(98-99%)It is the presenting complaint in 70% of patients with sclerodermafeatureLimited sclerodermaDiffuse sclerodermaRaynaud's phenomenon99%98%Secondary causes of Raynaud's phenomenon:Rheumatologic:SclerodermaSLERASjogren's syndromeDermatomyositisPolymyositisvasculitisDrugs:sympathomimetics(decongestants, diet pills)serotonin agonists(sumatriptan)chemotherapeutics(bleomycin, cisplatin,carboplatin)ergotaminecaffeinenicotineHaematologic disorders:cryoglobulinemiaparaproteinemiapolycythemiacold agglutininsVasospasm:migraine headachesMechanical:vibration injuryfrostbitethoracic outlet syndromevascular embolus or occlusionEndocrine disorders:hypothyroidismcarcinoid syndromepheochromocytomaRef: Harrison's 18/e p2763, 17/e p2096, 2101