Expansion
Sclera, conjunctiva, tongue and fingers
Expansion
Jaundice
- Best seen in the sclera in natural light, where elastin binds bilirubin
- Detectable clinically at a bilirubin above about 50 micromol/l
- Carotenaemia stains the skin and palms but spares the sclera, which is the distinguishing feature
- Look for the cause alongside: scratch marks and pale stools with dark urine in obstruction, stigmata of chronic liver disease, anaemia in haemolysis
Pallor
- Look at the conjunctivae, palmar creases, nail beds and the tongue
- Clinical assessment is insensitive; anaemia is a laboratory diagnosis
- Pallor of the palmar creases suggests a haemoglobin under about 7 g/dl
Cyanosis
- Requires about 5 g/dl of deoxygenated haemoglobin, so it appears early in polycythaemia and late or never in anaemia, regardless of oxygen saturation
- Central: tongue and lips, indicating a low arterial saturation, and therefore lung disease, right to left shunt or high altitude. It is always accompanied by peripheral cyanosis
- Peripheral: fingers, toes and nose, from reduced peripheral flow. Cold, Raynaud’s, peripheral vascular disease or low cardiac output. The tongue is spared
Other colours worth noting: the slate grey of haemochromatosis and amiodarone, the bronzing of Addison’s disease with buccal pigmentation, the plethora of polycythaemia, and the chocolate brown blood of methaemoglobinaemia, in which the patient is cyanosed with a normal arterial oxygen tension.