April 24, 2026 | Black & Kletz Allergy
More than 300 million people globally suffer from asthma, while allergic rhinitis (i.e., hay fever) and other allergic diseases, such as atopic dermatitis (i.e., eczema) and food allergies, affect between 10 and 30% of the worldwide population. The rapid rise in the prevalence of these diseases recorded over the last few decades, and their negative impacts on health-related quality of life, has stressed the need to recognize the environmental and modifiable risk factors associated with the development of these conditions. In the last decade or so, research has been directed on both prenatal and postnatal modifiable factors for allergic disease prevention, as these factors can affect the immune system in an important phase of its development. Breastfeeding seems to be one of the most significant postnatal factors that drives the development of the immune system in newborns and infants. Human milk has been shown to defend against early respiratory infections. Exclusive breastfeeding for at least the first 6 months of life continuing up to 2 years of age has been considered the gold standard for infant feeding.
Food Allergy:
Exclusive breastfeeding for the first 4 months of life may reduce the risk of IgE-mediated food allergies among infants, according to study results published in Annals of Allergy, Asthma and Immunology.
Exclusive breastfed infants had lower odds for egg, sesame, and peanut allergies. Infants exposed to cow’s milk in the nursery and later were breastfed exclusively had higher odds of developing cow’s milk allergies.
Certain infants who had delayed exposure to sesame had increased odds for developing sesame allergies. These findings support the expansion of early allergen introduction guidelines to include sesame, in addition to peanut and egg.
Asthma:
A recently published article in the Journal of Allergy and Clinical Immunology shed light on the relationship between the breastfeeding of infants and their subsequent development of asthma.
Exclusive breastfeeding has consistently been associated with a modest reduction in childhood asthma risk. However, this inverse relationship between breastfeeding and asthma is dependent on the length of time of breastfeeding and the type of asthma diagnosed in later childhood or adolescence.
Duration of breastfeeding:
- Shorter exclusive breastfeeding (e.g., < 2 months) tends to be associated with higher asthma/wheezing prevalence.
- Longer exclusive breastfeeding (e.g., > 4–6 months) tends to show progressively lower odds of preschool/early-childhood asthma outcomes.
- Associations with “any breastfeeding” (exclusive + partial) are generally weaker and more heterogeneous than with exclusive breastfeeding duration.
Types of asthma:
When asthma is separated into longitudinal phenotypes, longer exclusive breastfeeding shows the clearest association with:
- Persistent asthma (lower risk)
- Early transient wheezing/asthma (weaker/borderline effects)
- Little to no association with late-onset asthma (adolescent/adult onset)
Relationship to atopy / IgE sensitization:
- Longer exclusive breastfeeding has also been linked with a small reduction in IgE sensitization measured repeatedly from childhood into young adulthood.
- Breastfeeding may reduce early-life lower respiratory infections that drive wheezing/asthma diagnoses in early childhood.
Confounding by familial/host factors:
- Parental atopy/asthma, smoking, socioeconomic factors, childcare exposure, early infections, and/or environmental exposures may influence both breastfeeding duration and asthma development.
- Infants who develop early wheezing or eczema may prompt feeding changes indicating reverse causality.
- A few studies suggest a potentially stronger protective association after vaginal delivery than cesarean, plausibly via microbiome-related pathways.
Take home message:
Extended periods of exclusive breastfeeding (i.e., approximately 4 months or longer) are linked to a slightly reduced chance of childhood asthma. This protective effect is most evident for asthma that emerges in the first 10 years of life, as well as for persistent asthma, while the evidence is less conclusive for asthma with a later onset. It is interesting note that in 1936, Grulee and Sanford noted a significantly lower incidence of atopic dermatitis (i.e., eczema) in breastfed infants compared with formula-fed infants. Since then, the protective role of breastfeeding in the development of allergies has been in the forefront of allergy research, eventually leading to physicians recommending breastfeeding to new mothers.
The board certified allergy specialists at Black & Kletz Allergy will readily respond to your needs for further information in dealing with the subject of breastfeeding and allergies and/or asthma. The allergists at Black & Kletz Allergy have 3 convenient locations in the Washington, DC, Northern Virginia, and Maryland metropolitan area. Our offices are located in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA. We offer on-site parking at all of our offices and our Washington, DC and McLean, VA offices are Metro accessible. There is a free shuttle that runs between our McLean, VA office and the Spring Hill metro station on the silver line. To inquire about an appointment, please call our office or alternatively, you can click Request an Appointment and we will respond to you within 24 hours by the next business day. Black & Kletz Allergy treats both adults and children and we strive to provide the best and most current diagnostic and treatment techniques in the Washington, DC metropolitan area, as we have done for more than 5 decades.
