Navigating the Complexity of Dietary Restrictions
This brings us to what to do with an individual patient in the examination room. Because there is such widespread concern and discussion around this topic, it is important to at least briefly address it. If there are known food allergens that are being avoided, it is important to underscore the importance of continuing to avoid those foods, especially when there is actual evidence of true food allergy rather than sensitization alone. Historically, elimination diets often were recommended empirically, though more recent studies, meta-analyses, and guidance documents increasingly have recommended against them.3 In particular, there are major concerns for iatrogenic harm.
First, heavily restricted diets may result in nutritional and/or caloric deficiencies that can be dangerous and lead to poor growth.21 Practices such as drinking unpasteurized milk can expose children to dangerous infections, while feeding them exclusively rice milk can lead to severe malnutrition.22
Second, there is a dawning realization that children with AD placed on elimination diets may actually develop true IgE-mediated allergies, including fatal anaphylaxis, to the excluded foods. In fact, one retrospective review of 298 patients with a history of AD and no prior immediate reactions found that 19% of patients developed new immediate-type hypersensitivity reactions after starting an elimination diet, presumably due to the loss of tolerance to these foods. A striking one-third of these reactions were classified as anaphylaxis, with cow’s milk and egg being the most common offenders.23
It also is crucial to acknowledge that recommending sweeping lifestyle changes is not easy for patients, especially pediatric patients. Onerous dietary restrictions may add considerable stress, ironically a known trigger for AD itself.
Finally, dietary modifications can be a distraction from conventional therapy and may result in treatment delays while the patient continues to experience uncontrolled symptoms of AD.
Final Thoughts
Diet is intimately related to AD. Although the narrative continues to unfold in fascinating domains, such as the skin barrier and the microbiome, it is increasingly clear that these are intertwined and always have been. Despite the rarity of true food-triggered AD, the perception of dietary triggers is so widespread and addressing the topic is important and may help avoid unnecessary harm from unfounded extreme dietary changes. A recent multispecialty workgroup report on AD and food allergy succinctly summarized this as: “AD has many triggers and comorbidities, and food allergy is only one of the potential triggers and comorbid conditions. With regard to AD management, education and skin care are most important.”3 With proper testing, guidance, and both topical and systemic therapies, most AD can be brought under control, and for at least some patients, this may allay concerns about foods triggering their AD.