When I was diagnosed with lactose intolerance way back in 1978 I had literally never heard the words before. Today, just about everybody knows what LI is. That's great, except sometimes when it's a problem.
It's a problem because too many people now think that any problem with dairy products stems from LI. That's just not the case, and it's especially not the case for infants.
Lactose intolerance is the inability to manufacture the lactase enzyme. This ability does not even start to go away until about the age of weaning. You'll find very few healthy children under the age of three LI anywhere in the world.
Admittedly, any illness, surgery, medications, or injury that affect the small intestine can knock out the lactase-making ability. The most common cause of this is the old-fashioned "stomach flu," in reality a gastrointestinal illness. But this Temporary Lactose Intolerance (or Secondary LI) is, as the name indicates, normally temporary. It will go away in a few weeks as the intestines heal. (Truly serious damage from other causes may not heal, but this is extremely rare in comparison.)
How to explain the problems suffered by otherwise healthy children, who never seem to be able to tolerate dairy products? The most likely answer is a milk protein allergy. An allergy is an immune system reaction to the proteins in milk, a totally different process than the inability to digest the milk sugar, lactose.
The good news is that even a milk protein allergy is temporary, even though it seems to go on forever. I always reassure parents that the majority of infants will simply grow out of the allergy, usually by the normal time of weaning.
Of course, the parents always want to know how they can tell if their child will be one of them. I didn't have an answer. Until now.
On June 11, Timo Vanto, MD, of Turku University Hospital in Turku, Finland, gave a formal presentation titled "Persistent Cow's Milk Hypersensitivity: IgE Antibodies to Milk Have a Peak Earlier Than Skin Prick Test Wheals. Poster 579" at the 25th Congress of the European Academy of Allergology and Clinical Immunology (EAACI) in Vienna, Austria. You can found a report on the study at Doctor's Guide.
He did a double-blind study (the best kind) of 156 children who had been diagnosed with milk allergy at an average age of seven months. He then retested them at the ages of 1, 2, and 4 with the standard skin-prick test and measured the size of the wheals (swellings) that developed.
In the children who lost their allergies, the wheals were an average 2 mm in size in the diagnostic test, peaked in size at one year, and then dropped to 0.5 mm at 4 years. A full 77% of the children fit this pattern, meaning that three-fourths of them lost their allergies by age four.
The rest has a totally different pattern. Their diagnostic wheals were much larger, at 5.3 mm. They kept rising until the age of two, when they reached 8 mm. And they remained that average size even at age four. This clearly indicated that the allergy would persist.
Blood tests also showed two completely different patterns for antibody levels. The first group's S-f2 levels were 0.5 kU/L throughout the study. Those with a persistent allergy "started at a mean of 6 kU/L at diagnosis and peaked at 10.5 kU/L by 1 year. By 2 years they had dropped to 8 kU/L, and by age 4, they were at 4 kU/L."
So there are two independent ways of determining whether your child will grow out of a milk allergy. And they work best at different times, with the antibody serum levels predicting best up to the age of two and the skin-prick tests after that age. This should lead to much better diagnoses.
I have to warn everybody that one test is not necessary meaningful. Tests have to be replicated by independent researchers to ensure that chance or error didn't bias the results.
But this is great news. A readily available, easily performed test that predicts allergy persistence with high accuracy. This is the big one. Talk to your pediatricians or allergists about this. It may take some time before the results are accepted and the procedures are widely understood, but at least make sure that your doctors are looking into it.
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