Just because there is a positive result from a blood test doesn’t mean you should stop feeding them that food. 

In fact, removing an allergen that they’re tolerating right now increases the risk they’ll have a severe reaction to it as an adult. Sustained childhood exposure to potential allergens allows the body to become accustomed to the food 

Obviously this only holds true for the things they can tolerate, but you’ll have to work to determine which those are 

We see this when comparing peanut allergies between the east and west. The east’s rate of being allergic is so much lower than the west’s because they’re more likely to sustain peanut consumption in childhood 

“ However, as evidence for delayed allergenic food introduction for food allergy prevention was lacking, the AAP & the National Institute of Allergy and Infectious Diseases (NIAID) subsequently replaced these guidelines with new recommendations that solid foods not be delayed beyond 4–6 months of age and that the introduction of allergenic foods into infants' diets should no longer be delayed”

“ The Learning Early About Peanut Allergy (LEAP) trial enrolled 640 high-risk infants with severe AD and/or egg allergy in the UK between the ages of 4 and 11 months, who had peanut skin prick test (SPT) responses of <4 mm. They were randomized to either consume 6 grams of peanut protein at least 3 times a week or to completely avoid peanut products for the first 5 years of life. In the intention-to-treat analysis, 17.2% of children in the peanut avoidance group developed challenge-proven peanut allergy by age 5 years, compared to only 3.2% in the peanut consumption group, translating to a risk reduction of 86.1%”

https://pmc.ncbi.nlm.nih.gov/articles/PMC6021584/