Page 1  - Page 2
Index

A. Case study
When a 10-month-old boy was not gaining weight sufficiently, his mother took him to his pediatrician. The child was born after a normal gestational period and had a healthy birth weight. According to his growth curve, he had not gained sufficient weight since about 4 months of age. He had only recently been able to sit without support. He was thus somewhat behind in reaching his milestones. His mother breastfed him from birth, but switched to a cow's milk-based formula when her son was 3 months old, as she did not want to breastfeed any longer. Except for the past 2 weeks, he had drunk well. During these two weeks, he became less active, slept for longer periods and appeared to tire while feeding.

THOUGHT PROCESS:
What could be causing these symptoms? Could they be food-related? The causes of such symptoms in children of this age may or may not be related to food. To start, the pediatrician examined the child for all the obvious possible causes of these symptoms, e.g., cardiac disease, infection, etc. He did some routine tests, including urine and blood tests. The child's temperature was not raised.

When the doctor received the test results, the white blood cell count was normal and there were no signs of urinary tract infection. The only abnormality was that the child had iron deficiency anemia. Although the symptoms that the child was experiencing were some of the classical symptoms of anemia, he had no clinical signs. The hemoglobin was not decreased, but the MCV and MCHC were both decreased. This indicated that he was in the earlier stages of anemia, and would explain why he had no clinical signs.

THOUGHT PROCESS:
What could be the cause of the anemia? Should a medical practitioner in this case suggest iron-rich dietary sources and possibly a supplement? Or should other possible causes be excluded first? There are in fact many causes of iron deficiency anemia, which can be divided into the following groups:
a. Maternal iron deficiency during pregnancy
b. Insufficient dietary intake of iron due to inappropriate weaning practices (most often the cause)
c. Blood losses through stools or urine
d. Insufficient iron absorption
e. Insufficient red blood cell hemoglobin manufacturing (the least likely cause)

Additionally, the child's gestational age is an important factor to consider. Full-term infants have a reserve of iron that is adequate to meet their requirements for the first 4 to 6 months of life. In premature infants, the reserve will probably last only for approximately 6 weeks, and extra intake to prevent deficiency may be required. Because this child had a normal gestational age, we can assume that he had sufficient iron reserves until 4 to 6 months age. He had also received an iron-fortified formula since the age of 3 months.

To determine the cause of the anemia, the possibilities were investigated in the order of the most likely to the least likely cause:
a. Maternal iron deficiency during pregnancy:
This was not thought to be a problem.
b. Insufficient dietary intake:
Infants of this age can present with iron deficiency anemia due to an excessive intake of fluids such as unmodified milk, juice or tea. This can result in a comparatively lower solid food intake. A diet history revealed that the child had a sufficient dietary iron intake. He was receiving an iron-fortified formula plus additional dietary sources.
c. Losses through stools or urine:
The child had no history of bleeding or gastrointestinal illness, and the urine tests did not show any blood loss. The possibility of worm infestation always needs to be excluded, especially in children who often play outside or with pets. The child's stools did not show any signs of worm infestation. But when an occult blood test was done, it showed blood in his stools.

THOUGHT PROCESS:
Chronic occult bleeding resulting in anemia can have many causes. The most common ones are lesions in the gastrointestinal tract, and the ingestion of cow's milk in susceptible individuals. These are thus the possibilities that should be investigated first. Because the methods for diagnosing gastrointestinal lesions are more time-consuming and expensive than for diagnosing an adverse reaction to milk, it was decided to explore a sensitivity to cow's milk first.

Occult bleeding can be caused by severe milk allergy. Under the age of 1 year, however, occult bleeding is more likely to be caused by the irritation of the gastrointestinal lining by milk protein (a non-IgE reaction). This results in chronic low-level bleeding, leading to anemia.

THOUGHT PROCESS: Is it worth doing a skin prick test or a serum-specific IgE test to milk? There is a very good chance that it is a non-IgE-mediated reaction, and the test results would thus be negative. This would indicate only that it is not an IgE-mediated reaction. It would be prudent to exclude milk from the diet and observe whether the child's symptoms improve. By this method, both IgE and non-IgE-mediated reactions can be identified. If milk is not the cause of the occult bleeding, the symptoms would not improve with the exclusion of milk.

INTERVENTION AND RESULT:
When the cow's milk formula was changed to a soya formula, the stools were re-examined. No blood was present, which suggests that exposure to cow's milk caused the occult blood loss, which in turn caused anemia.

It was thus not necessary to investigate possibilities d or e (above) as potential causes of the anemia.

The child was continued on the soya formula and given an iron supplement for 3 months. After a few weeks, the child's symptoms resolved completely.

TIP for Allergy Advisor users: When searching for "milk", one has the opportunity to choose which type of milk (i.e., cow, mare, goat), which milk product or which individual protein component (e.g., casein, caseinate, whey, etc.) of milk one would like more information on. The "Adverse reactions" tab can be selected to reveal the adverse reactions to cow's milk that have been reported in the literature. They are divided into "IgE & Immune reactions" and "Other reactions".