Halting the March: Primary Prevention of Atopic Dermatitis and Food Allergies

Abstract

Atopic dermatitis (AD) is one of the most common inflammatory skin conditions, affecting 15% to 30% of children and 2% to 10% of adults. Population-based studies suggest that having AD is associated with subsequent development of other atopic diseases, in what is known as the "atopic march." We will provide an overview of studies that investigate primary prevention strategies for the first 2 diseases in the march, namely, AD and food allergies (FA). These strategies include emollients, breastfeeding, microbial exposures, probiotics, vitamin D and UV light, water hardness, and immunotherapy. Some studies, including randomized controlled trials on emollients and microbial supplementation, have found encouraging results; however, the evidence remains limited and contradictory. With regard to breastfeeding, microbial and lifestyle exposures, vitamin D and UV light, water hardness, and immunotherapy, the lack of randomized controlled trials makes it difficult to draw definitive conclusions. Current American Academy of Pediatrics guidelines support the idea that breastfeeding for 3 to 4 months can decrease AD incidence in children less than 2 years old. Recommendations regarding a direct relationship between breastfeeding on FA, however, cannot be made because of insufficient data. Regarding microbial supplementation, most guidelines do not recommend probiotics or prebiotics for the purpose of preventing allergic diseases because of limited evidence. Before definitive conclusions can be made regarding these interventions, more well-designed, longitudinal, and randomized controlled trials, particularly in at-risk populations, are required.

Keywords: Atopic dermatitis; Atopic march; Eczema; Food allergy; Primary prevention.

Figure 1.

Hypothetical examples of different atopic march patterns based on the severity and age of onset of atopic dermatitis (AD) or food allergy (FA), based on the specific FA. A) AD preceeds peanut allergy (PNA), which evolves to allergic rhinitis (AR) followed by asthma (AS) in early childhood. While AD resolved in most, PNA does not. B) Cow’s milk allergy (CMA) preceeds AD, and while CMA outgrows, AD does not resolve in all after early childhood. AS develops in early and AR in later childhood. C) AD and hens egg allergy (HEA) initiate the march (with similarly early age of onset) and resolve in most by late childhood, but AS and AR do not develop until early adulthood.