There is good evidence that early introduction and then regular consumption of peanut into an infant’s diet between 4-11 months of age decreases the risk of peanut allergy in those with severe eczema and/or egg allergy (two groups which appear to have a greater risk of peanut allergy). Another study which looked allergenic food introduction, including peanut, from 4 months of age in a population not selected for allergic risk factors, also showed a potential benefit for early peanut introduction in reducing peanut allergy.
Many parents are worried to introduce peanut into their infant’s diet, due to the potential risk of a severe allergic reaction, or a fatal reaction. Many delay the introduction or feed peanut butter outside emergency departments. Some guidelines are advocating skin prick testing or blood allergy testing before peanut is introduced. This is called screening. However others suggest not to overcomplicate matters, as these tests are not 100% reliable (i.e. may cause false positive reactions and thus delay peanut introduction). “Screen creep”may also occur, where children are then screened by skin prick or blood allergy testing for more foods than peanut which then may unnecessarily delay other food introduction (and thus have the potential consequence of then increasing the risk of food allergy). Furthermore many parents do not have ready access to an Allergist to perform and interpret these tests. It is also important to note that to date, there have been no reports of fatal anaphylaxis to peanut in infants < 12 months of age. In Israel where peanut introduction occurs early, there remains no case of fatal anaphylaxis in infants < 12 months of age.
So what would I do? Introduce peanut (in a paste form) into the infants diet between 4-12 months of age and then keep it up regularly in the child’s diet. If your child then does have a reaction, then see your doctor to determine what steps should occur next.
Further information about how to introduce allergenic foods can be found in this link produced by the Royal Children’s Hospital in Melbourne (note: for infants < 12 months, 1 teaspoon of peanut would be deemed a serve size; http://www.rch.org.au/uploadedFiles/Main/Content/allergy/RCH-HomeIntroductionofaNewFood.pdf)
A great article has also been recently published and is available on line for free, written by Dr Paul Turner and Prof Dianne Campbell talking about the pitfalls of screening the population for peanut allergy (http://jamanetwork.com/journals/jama/fullarticle/2603418)