Generalised weight loss may be apparent in changing facial and cervical contours. Excess tissue fluid (edema) is subject to the effect of gravity and although mostly observed in the lower limbs towards the end of the day, it may also be obvious within the face, particularly the eyelids, after a night’s sleep. Regional edema of the head, neck and upper limbs is seen in superior vena caval obstruction and the edema of myxedema may be particularly obvious in the eyelids, associated with skin and hair changes.

Whereas pallor and cyanosis of the hands may be due to the cold or local arterial disease, these signs in the warm central areas of the lips and tongue have a more generalised significance. The pallor of anemia is most noticeable in the mucous membranes, although the sign lacks specificity. The inner surface of the lower eyelid is an important area for demonstration (figure 19), as well as pallor of the mucous membranes and the palmer creases. Other abnormalities around the orbit include xanthelasma and an arcus senilis (figure 20).

Cyanosis is the blue discoloration given to the skin by deoxygenated blood. However, hemoglobin of 5g/dl is required to produce visible cyanosis; it is thus not detectable in severe anemia. Cyanosis is best observed in areas with a rich blood supply such as the lips and tongue. It may also be noted in the ear lobes and fingernails but these areas can react to cold by vasoconstriction, producing peripheral cyanosis in the presence of normal oxygen saturation.

Cyanosis is usually due to cardio-respiratory abnormalities, but may also occur at high altitudes, with methemoglobinemia and sulfhemoglobinemia. Cardiac conditions include a number of congenital abnormalities with a right-to-left shunt, whilst cyanosis may be related to hypoventilation (head injuries, drug overdose), chronic obstructive airway disease and mismatched arterial ventilation-perfusion (pulmonary embolism, pulmonary shunts, arteriovenous fistulae). Cyanosis is difficult to elicit in dark skinned people with anemia. Polycythemia is an excess of circulating red cells and may produce a purple-blue skin discoloration mimicking cyanosis, however, it is also prominent in the cheeks and thebacks of the hands.

Jaundice is yellow discoloration, due to excess circulating bile pigment (table 8, page 315). Mild degrees of jaundice are easily picked up from the staining of the sclera (figure 21). Be careful not to confuse the uniform yellow colour of jaundice with the yellowish peripheral discoloration of the sclera that can be seen in normal individuals. As the jaundice becomes more pronounced, there is yellow skin discoloration, and this may progress to yellow/orange or even dark brown with high levels of plasma pigment.