Washington.– When your child is allergic to nuts or peanuts, any food – even a Valentine's Day chocolate or the hot dog you serve at your Memorial Day picnic – needs to undergo an exhaustive ingredient analysis.  

And, as any parent who has a child with a nut or peanut allergy knows, Halloween can be an absolute nightmare. 

But you don't have to be a chemist to know which foods are OK and which ones could cause a potentially dangerous allergic reaction in your child. Reading labels and just knowing what the hidden ingredients are can go a long way toward keeping your child safe. 

About 1.5 million adults and children in the United States have an allergy to peanuts, and 50% of these people also are allergic to nuts or tree nuts. There's no typical age of diagnosis, although research indicates that the median age of first exposure is 14 months.  

And although many children outgrow allergies to milk, soy, and eggs, those with allergies to peanuts and nuts rarely outgrow their reactions. 

Although peanuts aren't true nuts but legumes (in the same family as peas and lentils), the reaction in people allergic to them is similar to the reaction in people who are allergic to tree nuts, such as walnuts, cashews, and pecans. 

An allergic reaction is when the immune system mistakenly believes that a harmless substance, in this case a nut or peanut, is harmful. It creates specific antibodies to that food to protect your body. The next time you eat that food, your immune system releases huge amounts of chemicals and histamines to protect your body, triggering an allergic reaction. 

You may not even recognize an allergic reaction, depending on the severity, the age of the child, and previous exposure to the allergen. The first signs of a reaction could be a runny nose, a skin rash all over the body, or a tingly tongue.  

Symptoms can quickly become more serious - including difficulty breathing, swelling of the throat or other parts of the body, rapid drop in blood pressure, and dizziness or unconsciousness.  

Other possible symptoms include hives, vomiting, abdominal cramps, and diarrhea. Symptoms usually appear within a few seconds to 2 hours after ingesting or being exposed to the allergen. 

A sudden, potentially severe allergic reaction, called anaphylaxis, can involve various systems in the body (such as the skin, respiratory tract, gastrointestinal tract, and cardiovascular system) and can be fatal. Anaphylaxis can cause a person's blood pressure to drop, airways to narrow, and tongue to swell, resulting in serious breathing difficulty, loss of consciousness and, in some cases, even death. 

Unfortunately, there's no cure for food allergies; the only way to help kids who have them is to stay away from the foods that will cause a reaction.  

If your child has been diagnosed with a nut or peanut allergy, learn everything you can about what to watch out for and the type of reaction your child will have if you come into contact with a nut or peanut (or nut and peanut ingredients in other foods).