Raynaud's pnenomenon is a vasospastic disorder generally involving arterioles of the hands, distal lower extrmeties, and ears.
It can be primary or secondary. The most common cause of the secondary pathology is connective tissue diseases arising from autoimmune dysfunction (ex. is Scleroderma, Lupus). My hypothesis is that you have a primary disorder, which is certainly preferable.
It manifest's in three stages:
1. Pallor: the initial vasospam causes decreased cutaneous blood flow causing numbness, parasthesias, and pain in the affected digits.
2. Cutaneous cyanosis: the digits develop a blue-purple color caused by deoxygenated blood flow in the capillary bed.
3. Hyperemia: reopening of the digital artery resulting in increased blood flow to the affected digits causing blushing of the skin.
It can be triggered by cold temperatures, emotional stress, and drugs like tobacco, caffeine, antihistamines, amphetamines, cocaine, and especially B-blockers (atenolol).
Obviously, attempt to avoid exposing your epidermis to frigid weather and attenuate emotional stress. If this is unavoidable or unsuccesful, I think calcium channel blockers are still the drug of choice(nifedipine). Although I would trully reccommend you attempt to control the situation without pharmacologic intervention.