Peanut allergy is a serious and life-long allergy affecting both children and adults.  It is essential that individuals with peanut allergy avoid even the slightest exposure to peanuts to prevent life threatening reactions.  The commonest manifestation of peanut allergy is with acute hives (or urticaria) following exposure.  However, some patients may rapidly develop severe angiodema, swelling of the face, bronchospasm and anaphylaxis following exposure.  They are an uncommon cause of exercise induced anaphylaxis.  Some individuals are so sensitive that they will develop symptoms if they kiss someone who has eaten peanuts are eat out of a food utensil which has been in contact with peanuts.

Peanut allergens
Peanuts are among the most allergenic foods.  The peanut allergen (ara h 1) is a glycoprotein with a molecular mass of 63 kilodaltons.  It is present in raw and roasted peanuts since it is heat stable.  It may contaminate peanut oils.  The proteins in peanuts can also be allergens, e.g. arachin, conarachin, peanut agglutinin and peanut phospholipase.

Sources of peanut allergens
Peanuts are widely used in Western and Oriental cooking.  Foods which often contain peanuts or peanut products include the following:  

Nutritive value of peanuts
Peanuts provide niacin, magnesium, Vitamin C, manganese and chromium in significant amounts and smaller amounts of potassium, Vitamin B6, folic acid, phosphorus, copper and biotin.  A peanut restricted diet will not negatively affect a growing child’s diet, since many other foods provide these same nutrients.

What about allergy to other nuts?
Peanuts are actually not nuts; they are legumes.  The majority of peanut sensitive individuals are not allergic to tree nuts such as pecans, walnuts or almonds.  However, some patients have multiple allergies and may also be sensitive to tree nuts such as brazil nuts, cashews, hazelnuts, macadamia nuts, pine nuts and pistachio.

How is peanut allergy diagnosed?
A history of an allergic reaction occurring within half an hour of exposure to peanuts suggests peanut allergy.  This should be confirmed by the CAP RAST test performed at a laboratory on a small blood sample.  The CAP RAST test is reliable, being both highly sensitive and specific.  If a strong history of peanut sensitivity is given, skin testing is potentially dangerous and should not be performed.  It is recommended that blood CAP RAST tests for possible sensitivity to soya and the other tree nuts should always be done.

    
      How is peanut allergy treated?

1. Avoid any possible direct exposure to peanuts.

2. Compile a list of possibly contaminated foods which should also be avoided.

3. It is important to carefully study labels of all packaged, processed foods, cereals and health foods.

4. Take particular care when eating out particularly at Oriental restaurants or at chidlren’s parties.

5. Caregivers in creches, school teachers, family members, friends and their mothers should be informed about the allergy and what to do in an emergency.

6. Wear a Medic Alert badge.

7. Always carry an injectable adrenaline syringe (e.g. Epipen or Anaguard) and be familiar with its use.

8. NEVER TAKE A CHANCE WITH UNKNOWN FOODS.
 

Copyright: Allergy Society of South Africa.
 Endorsed by ALLSA

This information sheet is obtainable from:
ALLSA
P.O. Box 88
Observatory, 7935
Cape Town,
R.S.A.

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