Infants and toddlers with sensitization to peanut often co-sensitized to tree nuts: Study

These findings highlight the potential importance of measuring specific IgE (sIgE) levels for tree nuts in peanut-sensitized children who have not yet consumed tree nuts. This research, led by Lara Meixner, MSc, from the Department of Pediatric Respiratory Medicine at Universitätsmedizin Berlin in Germany, sheds light on the need for careful allergy assessment in these young patients.

Infants with eczema are at high risk for food allergies due to impaired skin barriers. High household peanut consumption may increase peanut allergy risk. German guidelines recommend ruling out peanut allergy in atopic infants before dietary introduction. Rising plant-based diets may heighten tree nut allergen exposure, increasing allergy risks. Therefore, the researchers aimed to examine the frequency of sensitization to cashews, hazelnuts, and walnuts, along with their seed storage proteins, in peanut-sensitized infants and toddlers, as these may be linked to a high risk of clinical reactivity.

The study included infants and toddlers (≤2 years) referred to Charité—Universitätsmedizin Berlin, with specific IgE (sIgE) to peanut ≥0.1 kU/l. Blood and clinical data were collected during routine diagnostics, including oral food challenges (OFC) between 2007 and 2020. Sensitization to peanut, hazelnut, walnut, cashew, and their proteins (e.g., Ara h 2, Cor a 14, Ana o 3) was assessed using the NOVEOSTM immunoanalyzer, with sIgE ≥0.1 kU/l indicating sensitization. OFC risk for hazelnut and cashew was calculated using established probability curves. Among 101 peanut-sensitized patients (median age 16 months), 98% had eczema.

The findings of the study were as follows:

• 96% of patients (n = 97) had specific IgE ≥0.1 kU/l to at least one tree nut.
• Sensitization rates were highest for hazelnut (94.1%), followed by walnut (87.1%) and cashew (84.2%).
• 58.4% were sensitized to at least one 2S albumin, with 41.6% (n = 42) sensitized to Cor a 14 and Jug r 1, and 39.6% to Ana o 3.
• 80.2% were sensitized to all three tree nuts, and 26.7% to all corresponding 2S albumins.
• Peanut-sensitized infants ≤12 months old (n = 26) had high sensitization rates to tree nuts (88.5%) and 2S albumins (46.2%).
• 15.8% had a ≥90% predicted probability of allergy to hazelnuts and/or cashews.
• Almost all participants (98%) had eczema, a significant risk factor for sensitization and food allergies.

Our study at a tertiary care clinic reveals that most peanut-sensitized infants and toddlers with eczema are co-sensitized to tree nuts, with many at significant risk for allergic reactions.

"Measuring sIgE to tree nuts in peanut-sensitized children who have not yet consumed them should be considered. If sensitization is detected, an oral food challenge is recommended to assess clinical relevance," the researchers concluded.

Reference:

Meixner, L., Heller, S., Bluhme, F., Trendelenburg, V., Beyer, K., & Kalb, B. (2024). Infants and toddlers with sensitization to peanuts are often co-sensitized to tree nuts. Clinical and Translational Allergy, 14(11), e70008. https://doi.org/10.1002/clt2.70008