Why are my fingernails blue? They're not cold at all, just blue. Are blue fingernails always a sign of a heart problem? Pict >> http://goo. Gl/hsf6w

Cyanosis. Cyanosis often represents a low oxygen level, representing a cardiac or pulmonary problem. It merits the evaluation by a cardiologist or a pulmonologist.
Not uncommon. If they are always blue it can be a sign of cyanotic heart disease. If they are sometimes blue it can be a condition called raynaud's disease.Here is a reference: http://www.Nlm.Nih.Gov/medlineplus/raynaudsdisease.Html.