hi thanks for using healthcare magic Increase red cell count more than 6 millions is towards polycythemia vera. There are various causes for it like abnormality of bone marrow, genetic factor, high altitude, any tumor which is secreting erythropoetin etc. Various symptoms of it includes Headache, Dizziness, Itchiness, especially following a warm bath or shower, Redness of your skin, Shortness of breath, Breathing difficulty when you lie down, weakness in your hands, feet, arms or legs, Fatigue etc. he should consult a physician to find out the cause and further treatment. thanks