Well first off, a white, cold toe suggests lack of blood flow to the area. There are many reasons this could have occurred, and I'll listed a few, but please seek medical attention if it persists. First of all, was she exposed to cold for any length of time? If so, it may have been an exaggerated vasoconstriction in that toe; in that case it would resolve upon slow warming of the extremity. You would also expect this not to persist as long as the extremities are kept warm. Raynaud’s is a disease that occurs more commonly in women than men and results in idiopathic (cause unknown) vasoconstriction of the digits and toes (other areas may be affected as well) when exposed to cold or stress. If she has a first degree relative with this, it would make the diagnosis more likely. Another question would be did it occur at rest or while moving around or exercising? If it turned white with activity but resolved upon rest, you might consider things like peripheral artery disease; especially if she has risk factors like smoking, high cholesterol, high blood pressure, etc. To check blood flow you can wait until her toe looks normal then raise her affected leg about 45 degrees in the air (while she is lying down), for 1 minute. If there is paleness to the toe or foot, you would suspect inadequate arterial supply to that area. Pain might also be present. Other things that may cause excessive vasoconstriction are: Smoking, certain OTC cold medicines, some prescription meds, thyroid abnormalities and many others. Bottom line is, if this is recurring or worsening, you definitely want to get it checked out. Also, it might be a good idea to check her pulses when/if this occurs. Check her dorsalis pedis and posterior tibial arteries. Compare to normal foot for symmetry. Hope this helps.
