Jessica Savage, MD, MHS, a physician and researcher in BWH’s Division of Rheumatology, Immunology and Allergy, has been exploring the dramatic rise of food allergy in the past 20 years.

Jessica Savage, MD, MHS, a physician and researcher in BWH’s Division of Rheumatology, Immunology and Allergy, has wanted to specialize in food allergy since her training days at Johns Hopkins University School of Medicine.

She remembers a specific day in the allergy clinic when she met a patient with food-dependent exercise-induced anaphylaxis—the onset of allergic symptoms caused by eating a certain food or foods and then exercising within a few hours. When the food intake and exercise occur separately, the patient experiences no symptoms.

“It was the most interesting thing I ever saw,” said Savage, who joined BWH in 2012. “It almost defies explanation because we are beginning to better understand food allergy and exercise-induced anaphylaxis, but the combination is really hard to explain. So I thought, ‘I have to study that.’”

Today, through various studies, Savage is trying to discover the causes of the dramatic rise in the number of people diagnosed with food allergy in the U.S. in the past 20 years.

“Our best evidence suggests a two-fold rise in the last 20 years for all food allergies,” she said. “For peanut allergy, it may be faster, with a four-fold increase over fewer than 15 years.”

Although certain risk factors for developing food allergy, such as genetics and environmental influences, have been identified, researchers still don’t know the definitive causes.

Savage explains that food allergy generally starts in infancy and is either outgrown sometime in childhood or persists through adulthood. The most common allergy that persists to adulthood is peanut allergy, while children’s allergy to milk and egg usually disappears by adulthood.

It is also possible for people to develop an allergy later in life that was never an issue during childhood. Common examples include allergy to nuts, seeds, fish or shellfish. Adults can also develop an allergy to fresh fruits and vegetables, which is often related to their environmental allergies.

“Allergy is such an outpatient field, and medical school trainees don’t have a lot of exposure to it, but it is so important,” said Savage. “It deeply affects people’s quality of life. Even though it’s not always a matter of life or death, people can be seriously bothered by allergic problems.”

Savage currently leads the newly established Brigham and Women’s Hospital Food Allergy Center of Excellence, which provides care for patients with known and suspected food allergy. The center is also involved in cutting-edge research, with funding from the National Institutes of Health, private foundations and industry.

Savage is actively involved in two main research areas. She is studying antimicrobial chemicals found in personal care products—such as parabens and phenols—and their possible connection to the increase in reported food allergies. Specifically, Savage is seeking to find out if these chemicals change the human microbiome, affecting the immune system’s development and response to stimuli.

Savage and colleagues are conducting a longitudinal study using data from several randomized trials involving pregnant women. They are comparing the levels of antimicrobial chemicals in pregnant women’s urine with their children’s later lack or development of food allergy.

Savage is also working with colleagues at MGH and a pharmaceutical company to identify a better biomarker for milk allergy in children by figuring out why some children with milk allergy can tolerate cooked milk and some cannot.

“If a child comes into the clinic, we are trying to find out if we can predict his or her future ability to tolerate milk,” said Savage. The hope is that this could someday be applied to peanut, egg and other allergies.

A recent study that received significant media attention showed that early introduction to peanut can protect some children from developing peanut allergy.

“The results of this study was eye-opening for the field, but there is still a lot of work to be done,” said Savage. “This doesn’t explain everything about the high prevalence of allergy.”

Savage says researchers don’t know why some children outgrow allergies and some do not. Additionally, the age by which children do tend to outgrow allergies has been inching up, from age 5 in the 1980s to closer to 10 today.

“Something is changing,” said Savage. “Children are keeping their food allergy longer. We are trying to find out why.”

To learn more about Savage’s work or enroll in available research studies, visit the Food Allergy Center website.