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Lactose Intolerance, Diarrhea, and Allergy

Maryelle Vonlanthen, MD
from Breastfeeding Abstracts, November 1998, Volume 18, Number 2, pp. 11-12.

Signs and symptoms of lactose intolerance, diarrhea, and allergy may occur in exclusively breastfed infants. These problems may be the result of sensitivity, intolerance, or allergy, terms not always defined correctly in the literature. An adverse reaction is any abnormal reaction to food or additives; food intolerance is any abnormal physiologic response to ingested food; and food hypersensitivity (true allergy) involves an immune reaction to ingested substances, often synonymous with IgE-mediated reactions. Immune reactions to ingested substances are classified into two broad types: IgE, with involvement of the cardiovascular system, respiratory system, and/or skin; and milk protein enterocolitis, limited to gastrointestinal involvement. The top three food antigens are cow's milk protein (mostly the beta-lactoglobulin component), soy bean protein, and egg white, followed by peanuts, meat, and fish, especially cod. About 50 percent of infants allergic to cow's milk protein will also be allergic to soy bean protein, and soy is virtually everywhere in processed foods. Allergens can be hidden in minute amounts, even occurring as cross contamination during food processing.


A complete allergy history of the parents is important in the diagnosis of infant food allergy. If one parent has allergic disease, the infant has a 30 percent risk of developing allergic disease. This risk doubles if both parents have allergic disease. In families with a high risk of atopic disease, the cord blood can be examined for high IgE levels. The presence of high levels of IgE may correlate with the occurrence of IgE-mediated disease. There are a number of studies in the literature which suggest that babies may become sensitized in utero if there is a strong family history of allergies.9 Mothers may be advised to avoid suspect foods during all or part of their pregnancy and to continue to avoid these foods during lactation. The research indicates that this practice does not decrease the incidence of allergy by two years of age, but it does delay the onset of allergy.

For a baby, just about anything can be a symptom of allergic disease. IgE-mediated reactions can include symptoms in the upper gastrointestinal tract such as nausea, vomiting, reflux, refusal to eat, and eating ravenously; lower GI symptoms may include blood in stools and diarrhea. IgE-mediated disease can also cause respiratory symptoms such as wheezing and perpetual congestion; atopic dermatitis, eczema, and various rashes; an extreme reaction is anaphylaxis which leads to cardiovascular collapse and shock. Symptoms of non-IgE-mediated allergic disease (or cow's milk colitis) are usually limited to the lower GI tract, causing diarrhea and blood in the stools. The presence of symptoms outside the gastrointestinal system generally indicates IgE-mediated hypersensitivity.

Research has shown that foreign proteins do pass into breast milk and can cause allergy.1, 3 There are case reports in the literature of cow's milk protein in breast milk causing anaphylactic shock in infants.4 The possibility of allergic disease should be considered when a breastfeeding baby is not acting quite right, especially if the baby is not growing well.

In diagnosing allergy, a complete history, including information about the baby's behavior, is important. Sleeping patterns, colicky behavior, and crabbiness may be signs of allergy. A complete physical is also important. Sometimes it is helpful to examine a baby just after a feeding because some babies will react immediately, providing clues to the practitioner.

Laboratory data may show an elevated white blood cell count, peripheral eosinophilia, and/or blood in stools. GI endoscopy with biopsies and skin tests can also be useful. It is important to note that these symptoms of atopic disease such as diarrhea or rectal bleeding can have other causes such as lactose intolerance, rectal fissures, Crohn's disease, infectious etiologies, and clostridium difficile colitis.

Identify patients at risk and weigh options based on family history. A study of positive predictive values (ppv) of various indicators of allergy shows that peripheral eosinophilia had a 10 percent ppv, low hemoglobin had a 48 percent ppv, and low albumin had an 81 percent ppv.5 Measuring albumin is an effective tool for the practitioner especially when endoscopy is not available. The gold standard of allergy testing remains a food challenge demonstrating the return of symptoms following the reintroduction of food after an improvement during elimination diet.7


If the only symptom is colicky behavior, fussiness, gas, and/or loose stools, it can be helpful to examine the feeding pattern before starting an elimination diet. Woolridge10 noted that when mothers fed from both breasts at each feeding, infants experienced overconsumption of foremilk, receiving large amounts of skim milk and lactose.10 Overconsumption of lactose caused green, watery, loose stools, gassiness, and colicky behavior. Most mothers gave a history of limited time at the breast and/or very forceful milk ejection that forced the baby to pull off the breast to keep from choking. When the feeding pattern was changed to nursing fully on one breast, offering the second breast only if the baby wanted to continue, the babies improved.

If an elimination diet is necessary, it should begin with the top offender, cow's milk protein. Once the mother's elimination diet has started, it can take anywhere from a few days to six weeks for an infant to show improvement, making it difficult to use elimination as a "test" to prove or disprove allergy to a particular protein. Many infants will outgrow their allergies by about 6 to 18 months. After a period of elimination, infants should be rechallenged with the offending protein to determine the need to continue with the diet.

Research has shown that allergy injections are not an effective treatment for food allergies.6 The best treatment is prevention.


Food allergies in breastfed infants are usually to substances passing into breast milk, not to breast milk itself. There are different types of allergies which may present multiple symptoms. Many symptoms are non-specific which may lead to over- or under-diagnosis. Most infants will respond to elimination of cow's milk from the mother's diet. It is not necessary to use elimination of multiple foods as a first line of therapy.

This article is based on a presentation given by Maryelle Vonlanthen, MD at the LLLI 1998 Seminar for Physicians on Breastfeeding. Dr. Vonlanthen, a gastroenterologist, is Assistant Professor of Pediatrics, University of Arkansas Medical Sciences, and is a member of LLLI's Health Advisory Council.


  1. Cant, A., R. A. Marsden, and P. J. Kishaw. Egg and cow's milk hypersensitivity in exclusively breastfed infants with eczema and detection of egg protein in breast milk. Br Med J 1985; 291:932-35.
  2. de Boissier, D. et al. Multiple food allergy: A possible diagnosis in breastfed infants. Acta Paediatr 1997; 86(10):1042-46.
  3. Lake, A. M., P. F. Whitington, and S. R. Hamilton. Dietary protein-induced colitis in breastfed infants. J Pediatr 1982; 101(6):906- 10.
  4. Lifschitz, C. H., H. K. Hawkins, C. Guerra, and N. Byrd. Anaphylactic shock due to cow's milk protein hypersensitivity in a breastfed infant. J Pediatr Gastroenterol Nutr 1988; 7(l):141.
  5. Machida, H. M., A. G. Catto Smith, D.G. Gall et al. Allergic colitis in infancy: Clinical and pathological aspects. J Pediatr Gastroenterol Nutr 1994; 19(1):4-6.
  6. Osvath, P., K. Kelenhegyi, and E. Micksey. Comparison of ketoifin and DSCG in treatment of food allergy in children. Allergol Immunopathol 1986; 14:515-18.
  7. Powell, G. Milk and soy induced enterocolitis of infancy. J Pediatr 1978; 93(4):553.
  8. Sorva et al. Beta lactoglobulin secretion in human milk varies widely after cow's milk ingestion in mothers of infants with cow's milk allergy. J Allergy Clin Immunol 1994;93:787.
  9. Wilson et al. Severe cow's milk induced colitis in an exclusively breastfed neonate. Clin Pediatr 1990; 29(2): 77
  10. Woolridge, M. W. and C. Fisher. Colic, overfeeding, and symptoms of lactose malabsorption in the breastfed baby: A possible artifact of feed management. Lancet 1988: 2(8607):382-84.
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