Peanut Allergy - the do's and don'ts

Peanut allergy is prevalent in 10% of children in the US.  Almost all children who have a peanut allergy have other allergic conditions.

Typical types of reactions that occur with peanuts:

Reactions related to skin contact typically cause local skin reactions and are unlikely to have life-threatening symptoms.

Accidental contact to the eye with peanut butter causes swelling of eyes, redness and itching.

Inhalation of peanut vapors from cooking or airborne particles from peanut dust or peanut flour can trigger an allergic reaction varying from respiratory symptoms to life-threatening symptoms. However peanut butter contains volatile vapors but no peanut proteins and therefore should not trigger allergic reactions.

Individuals allergic to birch pollen may also have itchy mouths with peanuts which typically do not progress. This condition is known as Oral Allergy Syndrome.

Why is peanut more allergic than other foods?

Here are some theories:                             

Molecular make-up: Disulfide bonds contained in peanuts make the proteins extremely stable at high temperatures; whereas most other foods breakdown to smaller proteins therefore losing their allergic potential.

Peanut processing which is done by dry roasting makes peanuts more allergic than other methods, like boiling or frying.

Whipping or emulsifying peanuts for peanut butter prevents separation of oil, bringing the peanut protein in direct contact with the oil thus increasing the allergic content.

 Risk Factors for The development of Peanut Allergy

A history of any type of allergy (Hay Fever, Asthma, Eczema, drug, insect or latex).

A family history of peanut allergies.

Siblings of children with peanut allergy.

Children with Eczema who use crude peanut oil-based moisturizer on active rashes (no longer available in the US where highly refined peanut oils are used).

A delay in the introduction of peanuts beyond 4-6 months (Retrospective studies now show that peanut allergy has doubled in children who had a delayed introduction of peanuts at 3 years).

Here are some other facts of peanut allergy

Single allergy to peanuts is a rare phenomenon with less than 5% of children showing no other allergy.

Peanut allergy is a marker for other allergic diseases.

Individuals whose asthma is poorly controlled are more likely to have fatal outcomes with peanut allergy.

Individuals with peanut allergy are more likely to have severe asthma symptoms.

Eczema is a common condition in children with a peanut allergy.

Clinical Characteristics of Reactions to Peanuts

Outgrow Peanuts? When should you check?

Experts believe children and adults with a peanut allergy should be checked yearly with a blood test (CAP-RAST).  If the test is negative or low (less than 2 KUA/L), patients should be offered a food challenge to peanuts. Once the patient has passed the food challenge then the person should continue to eat peanuts monthly (about one peanut butter sandwich).  Monitoring should continue for at least one year to assure no recurrent symptoms.

Can peanut allergy recur after passing a challenge?

Infrequent eating of peanuts can cause resensitization. In small studies conducted, those children who regularly ate peanuts (at least once per month) did not get resensitized to peanuts.

Who should not be challenged?

If skin testing shows wheals greater than 6 mm or if blood tests show values greater than 14-15 KUA/l (Kilo-units of allergen/liter) the likelihood of an allergic reaction to peanuts is high

Dietary recommendations

Patients should be aware of accidental exposure from small amounts of hidden peanuts while eating out in restaurants (Thai, Malaysian, Vietnamese, Chinese, Indian and Mexican) and bakeries, even in foods considered "safe"

Labeling of food items that say "may contain peanuts" typically consist of candy, baking mixes and chocolate. The current recommendation is to avoid all foods with this "advisory labeling"

In those individuals who have life-threatening reactions to peanuts we recommend avoiding eating lupines and all tree nuts. Other legumes including, peas, soy and beans can be eaten safely

Management of Acute Reactions

A US-based registry of individuals with peanut allergy states that subsequent reactions to accidental ingestion of peanuts were more severe than the initial reaction

All patients with peanut allergy (including those with non-life threatening symptoms) must carry an Epipen and should be trained in its use

All patients should be counseled in the proper management of accidental exposures to peanuts

What's ahead?

The current cutting edge in peanut research is known as Oral Induction of Tolerance (OIT) where large studies are being conducted in various academic centers in Europe, Australia and the US. As these studies unfold we will be better prepared to treat peanut allergy. Currently, Oral Induction of Tolerance is not yet ready for clinical practice. Other research includes trials with Chinese herbal remedies and peanut-based immunotherapy (vaccine).