Clinical, laboratory, and therapeutic differences between immunoglobulin E-mediated and non-immunoglobulin E-mediated cow's milk protein allergy in children.

Background: Although breast milk is ideal for newborns, in some cases, it is replaced with cow's milk, which contains proteins that increase the risk of cow's milk protein allergy (CMPA).

Aim: To evaluate CMPA prevalence in Bahrain and compare clinical characteristics of children with immunoglobulin E (IgE)- and non-IgE-mediated CMPA.

Methods: This retrospective cohort study examined children with CMPA diagnosed at the pediatric gastroenterology outpatient clinic of the Salmaniya Medical Complex, Bahrain, between 2014 and 2022, and assessed CMPA prevalence. Clinical presentations, laboratory findings, dietary modifications, and outcomes were compared between children with IgE-mediated and non-IgE-mediated CMPA. Categorical variables were compared using Fisher's exact test or Pearson's χ ² test, whereas continuous variables were compared using Student's t-test or the Mann-Whitney U test.

Results: Of 8332 patients, 6022 (72.3%) adhered to their appointment. Of them, 618 (10.3%) were suggested of having CMPA and 595 (96.3%) were included; CMPA prevalence was 2%. Most patients were Bahraini (93.8%) and males (55.3%). Non-IgE-mediated type accounted for 77.3% cases and IgE-mediated type, 22.7%. IgE-mediated CMPA presented more in boys (P = 0.030), and later in life (5.1 months ± 4.5 months vs 4.2 months ± 4.2 months, P = 0.016, 95%CI: 0.08-1.73), had more associated diseases (P < 0.001); and presented with more cutaneous (P = 0.024) and respiratory (P = 0.003) manifestations, severe symptoms [rash/dry skin (P = 0.031), facial swelling/angioedema (P = 0.003), failure to thrive (P = 0.013), apparent life-threatening event (P < 0.001)], and positive physical findings (P = 0.002) than non-IgE-mediated CMPA. Most patients were exclusively fed cow milk formula (50.3%). The amino acid-based formula (AAF) was most prescribed (60.5%) with no difference between the two types (P = 0.173). Although breastfeeding was recommended to 49.6%, only 8.2% were exclusively breastfed. IgE-mediated CMPA was associated with a longer follow-up duration than non-IgE-mediated CMPA (17.3 months ± 14.0 months vs 13.5 months ± 13.4 months, P = 0.005, 95%CI: 1.1-6.3).

Conclusion: This study revealed a high CMPA prevalence with clinical differences between both types that can influence treatment. AAF was most prescribed, while breastfeeding with dietary modification is rarely applied.