Know the different nut families. Affected patients often have allergy symptoms in relation to particular categories of nuts. For example, an allergy to walnuts often coincides with an allergy to pecans. Other nut families include: pistachios and cashews; beechnuts and chestnuts and hazelnuts, filberts and hickory nuts. Brazil nuts, macadamia nuts and almonds don`t seem to be related to any other nuts.
Be cautious of tree nuts if you have an allergy to peanuts. While people with allergies to tree nuts aren`t always allergic to peanuts, those with a peanut allergy are significantly more likely to be allergic to other types of nuts as well. Cashews, walnuts and pistachios, in particular, tend to cause similar reactions because they contain the same allergenic proteins as peanuts.
Note the first symptoms of an allergic reaction. Though all allergic persons should know the signs, children especially should be warned to watch for tongue swelling, hives, tightening of the throat and vomiting after possible exposure to a tree nut or tree nut product. These symptoms can signal the beginning of a very serious systematic reaction known as anaphylaxis, which needs immediate medical attention.
Pay attention to persistent itchy skin rashes, nasal congestion, diarrhoea and hives. These lesser allergy symptoms can be related to chronic exposure to the allergenic proteins in nuts but, if they occur within 2 to 4 hours of consumption, can be an indication that more severe symptoms may develop.
Ask questions and read labels carefully. Many products have "hidden" nuts in them that can cause an allergic reaction. Be specifically cautious with candy, cookies and other deserts, donuts, granola bars, pesto sauces, suntan lotions, shampoos and flavoured coffees.
Information sourced from ehow.com