For years and years the only way to handle a potential peanut allergy in a child was to avoid peanuts at all costs. But that all changed two years ago when the National Institutes of Health put out new guidlines recommending a shift. That parents should introduce peanut-containing foods into the diets of babies as young as 4 months in order to check for a food allergy. 
    But that doesn't mean you should just do it.
    The guidelines also divide babies into three subsets to help determine if peanut butter testing should take place. And no matter what, before testing any baby for peanut allergy, discuss it first with your pediatrician and determine if your baby should see an allergy specialist. 

WHY THE GUIDELINE CHANGE?
The guidelines were based on findings published in the New England Journal of Medicine in 2015. Researchers found that babies at high risk of developing a peanut allergy who were fed the equivalent of 4 heaping teaspons of peanut butter each week starting between 4 and 11 months were about 80 ercent less likely to develop an allergy by age 5 than similar babies who were not fed peanut butter.
    These are the three subset baby groups:

• Babies with severe eczema who need presciptions creams and/or who have a known egg allergy (High-Risk): Peanut testing is recommended for babies in this group. If your baby is in this group, talk with your pediatrician at the 2- or 4-month check up and set a plan in place for testing.

• Babies with mild to moderate eczema: No testing needed, although you should discuss allergies with your doctor. These babies may try peanut products beginning at about 6 months.

• Babies who don't have any eczema or known food allergy: No testing needed. Babies can have peanut products based on family preference beginning at 6 months.

Peanut Testing Babies ... Advice for Parents:

While the idea of testing your high-risk baby for peanut allergy may be stressful, it's important to know that doctors and parents have been doing it successfully for two years now.
    "If we can prevent 80 percent of kids from developing peanut allergies, that's thousands of kids that we can hopefully prevent this peanut allergy," says John Hemler, M.D. with Vanderbilt University Medical Center. 
    Before testing your baby for a peanut allergy though, discuss it thoroughly with your pediatrician for the best results.

  • If your baby is considered "high risk for peanut allergy," determine with your pediatrician how and when to introduce peanuts. Ideally peanut-containing products should be introduced to these babies as early as 4 to 6 months. Doctors DO advise that these babies have an allergy evaluation or allergy testing prior to trying any peanut-containing product. Your doctor may also require the introduction of peanuts be in a supervised setting (e.g., in the doctor's office).

  • Babies with mild to moderate eczema are also at increased risk of developing peanut allergy. These babies should be introduced to peanut-containing products around 6 months of age; peanut-containing products should be maintained as part of their diet to prevent a peanut allergy from developing. These infants may have peanut introduced at home (after other complementary foods are introduced), although your pediatrician may recommend an allergy evaluation prior to introducing peanut.

  • Babies without eczema or other food allergies, who are not at increased risk for developing an allergy, may start having peanut-containing products and other highly allergenic foods freely after a few solid foods have already been introduced and tolerated without any signs of allergy. As with all infant foods, allergenic foods should be given in age- and developmentally-appropriate safe forms and serving sizes.

INTRODUCING PEANUTS
One way of introducing peanuts safely is to mix a couple of teaspoons of smooth peanut butter with a couple of teaspoons of warm water until it has a smooth, soupy consistency, allergists concur.

Source: American Academy of Pediatrics