Allergies in Infants: Symptoms, Causes & Treatment

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Infants and Allergy

As in adults, babies are more likely to suffer from allergic disease if there is a family history. The risk is especially strong if both parents have allergies; if only one parent does, the risk is slightly higher if the mother is the allergic one than if the father is (Prescott & Tang 2005).

Food allergies are common in infants. Cow’s milk allergy may be the most common, affecting 2% to 3% of infants, though most will outgrow the allergy (Dowshen 2008). Other kinds of infants can be found in infants, such as dust mite allergy. Dust mite allergy has even been suggested as a possible cause of Sudden Infant Death Syndrome (SIDS), though research so far has been inconclusive (Jenkins 2008).

Diagnosing Food Allergies in Infants

Food allergy symptoms consist of variable and non-specific gastrointestinal symptoms such as gas, bloating, excessive spitting up, and uncontrollable crying, which may occur immediately after exposure or after a delay (de Boissieu & Dupont 2000). Other symptoms include skin rashes, nasal congestion, and failure to gain weight (MDHSS n.d.). Diagnosis is done through skin testing, IgE testing, and intestinal biopsy to check for eosinophils, a type of white blood cell and the culprit behind infant food allergy. Diagnosis can be confirmed through an exclusion diet (de Boissieu & Dupont 2000).

When solids are introduced, the common recommendation is to introduce only one new food every week or so (for example, see MDHSS n.d.). If a food allergy develops, this method of introduction makes it easy to pinpoint the offending food without the need for an elimination diet; the food that was new at the time of symptom onset is assumed to be the problem.


Although current consensus is to recommend exclusive breastfeeding in the first 4-6 months of life for babies at high risk of developing allergies, studies have shown that the protective effect is relatively small, and it may be countered with a slightly higher risk of allergy later in life (Prescott & Tang 2005). Exclusive breastfeeding is nevertheless considered the best nutritional course. It is not necessary for pregnant or breastfeeding mothers to avoid allergens, as there is no evidence that maternal allergen exposure will cause allergies in the baby (Prescott & Tang 2005).

Hydrolyzed formula, in which proteins are broken down, is less likely to cause allergy than either regular cow’s milk formula or soy formula, both of which are potentially allergenic (Prescott & Tang 2005).

Though clinicians commonly recommend avoiding allergenic foods such as peanuts and shellfish in infants and very young children, there is little or no evidence that this actually provides a protective effect against allergies. On the other hand, it causes no harm to children, so parents may choose to avoid these foods anyway, “just in case” (Prescott & Tang 2005).