<s>[INST] My 15 year old daughter has noticed twice in the last week and her volleyball team noticed also that her fingernails, hands and forearms were a blueish/purplish color. The second time it was just her hands and fingernails stayed this color longer, then skin goes back to healthy color. [/INST] Hello, Thank you for your contact to Chat Doctor. I understand your health concern, if I am your doctor I suggest you that this is the sign of peripheral cyanosis. The reason for such a condition may be some heart disease, or some kind of poisoning, or some large blood vessel disease. But exact diagnosis and so management can only be possible after your confirmation diagnosis. In my advice you should visit to the nearby doctor for general check up and diagnosis. I will be happy to answer all your future concern. Thank you, ChatDoctorInfectious disease specialist. Wish you the best health at Chat Doctor. </s>