Pediatric emergency medicine trisk 1195 1195

CHAPTER 62 ■ PALLOR
SONAL N. SHAH

INTRODUCTION
Pallor, or the absence of skin coloration, is a relatively common problem in
childhood. Throughout the world, the presence of pallor is often used as a
screening tool to identify illness. The development of pallor can be acute and
associated with a life-threatening illness, or it can be chronic and subtle. It may be
first noted by someone who sees the child infrequently. The onset of pallor can
provoke anxiety for parents who are familiar with descriptions of the presentation
of leukemia in childhood. In some instances, only reassurance may be needed, as
in the case of a light complexioned or fair-skinned, nonanemic child. Even if
there is a hematologic cause for the pallor, it is often a temporary condition
readily amenable to therapy. However, pallor can portend a severe disease, and
especially when acute in onset, can herald a true pediatric emergency for which
rapid diagnosis and treatment are essential.
The degree of pallor depends on the concentration of hemoglobin in the blood
and the distribution of blood in the blood vessels of the skin. Any condition that
decreases the concentration of hemoglobin or alters the distribution of blood
away from the body’s surface may present as pallor. Clinically, pallor caused by
anemia can usually be appreciated when the hemoglobin concentration is below 8
to 9 g/dL, although the complexion of the child and the rapidity of onset may
influence this value.

DIFFERENTIAL DIAGNOSIS
The differential diagnosis for nonhematologic causes of pallor is outlined briefly
in Table 62.1 and hematologic causes in Table 62.2 . The concentration of
hemoglobin in the blood can be lowered by three basic mechanisms: decreased
erythrocyte or hemoglobin production, increased erythrocyte destruction, and
blood loss. The most common causes of pallor and anemia seen in the emergency
department (ED) are iron deficiency and blood loss ( Table 62.3 ), but several

less common diseases remain important considerations.

Decreased Production of Hemoglobin and Red Cells
Nutritional Anemias