How are APOE and allergy related?

The relationship between APOE and allergies is not clearly established in science. APOE (apolipoprotein E) is primarily known for its role in lipid metabolism and Alzheimer's disease risk. Some studies suggest that carrying the APOE ε4 allele may be associated with a slightly increased risk of allergic conditions such as asthma or atopic dermatitis, possibly through immunomodulatory effects. However, findings are inconsistent, and effect sizes are small. There is no clinical recommendation to test APOE for allergy prediction. Allergy genetics are polygenic, involving many genes with small effects. A direct causal link between APOE and allergies is not proven. Therefore, such a test should not be used for medical decisions.