What is the difference between true and pseudo cyanosis?

True - increased concentration of deoxygenated hemoglobin in the blood capillary (> 5 g / dL) or presence of pathological hemoglobin (most often methemoglobin> 0.5 g / dl) pseudo - abnormal pigment in the skin (drugs - chlorpromazine, amiodarone, minocycline; heavy metals - silver, gold