Most cases of food allergies occur when someone with a genetic predisposition produces specific IgE antibodies to the certain protein of a particular food.    When these IgE antibodies react to a specific protein, the release of chemicals from cells is triggered.
Allergic symptoms include hives, swelling of the lips and tongue, trouble breathing, a drop in blood pressure and even loss of consciousness. They can appear from within minutes to several hours after a person has eaten the food to which he or she is allergic.

Although all foods can cause an allergy, peanuts, tree nuts, fish, shellfish, eggs, soy, milk and wheat account for 90 percent of all food allergies. Peanut and tree nut allergies affect about 1 percent of the population.  Peanuts are the leading cause of severe allergic reactions, followed by shellfish, fish, tree nut and eggs. 

Studies have shown that one-third of people with a peanut allergy have experienced a severe allergic reaction.  The first allergic reaction to peanut or tree nut develops in most children between 14 and 24 months of age. The peanut or tree nut allergy was once considered lifelong, yet new research has determined that up to 15 to 20 percent of sufferers will actually outgrow the allergy by school age.  This is especially true if your child has few other food allergies, has a low peanut IgE level as shown on a blood test, or has a mild reaction to skin prick test at a time of reassessment.

The peanut is in the legume family, along with peas, lima beans, lentils and soybeans, just to list a few. If you are allergic to peanuts, it does not necessarily follow that you will be allergic to these other legumes and be required to avoid them also.  Tree nuts include almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachio nuts and walnuts. Although the peanut is not considered a tree nut, it is recommended that peanut-allergic patients avoid all tree nuts, and vice versa, as an extra precaution.

Allergy shots have not been successful for patients with peanut or tree nut allergy. Until a cure is found, the only "cure" for the peanut or tree nut allergy is to stay away from all peanut and tree nut products.  Read labels of every food that you eat. Peanuts and peanut products can show up in many unsuspecting foods. In highly sensitized people, even trace amounts can induce a severe allergic reaction.

The principal treatment of acute severe allergic reaction is epinephrine. People with peanut or tree nut allergy should carry self-injection devices such as EpiPen with them at all times.  After epinephrine is administered, they should be observed for the next four to eight hours at a medical facility and receive additional treatment, if necessary.

Non-generalized allergic reactions are treated with a high dose antihistamine, while anaphylaxis requires immediate medical treatment with epinephrine and possible corticosteroids, in addition to the antihistamines.  Unfortunately, strict avoidance of the allergy-causing food is the only way to avoid a reaction.

Allergies from eggs common in kids 

Egg allergies are one of the most common food allergies found in infants and children.
In general, reactions are not as severe as those from peanut, nut, shellfish, or fish allergies, though severe reactions can occur. Most children outgrow egg allergies before five years of age, but some people suffer for a lifetime. The primary food allergens present in eggs are the certain proteins in the egg white.

While cooking can alter the protein of a raw egg, it may not be sufficient to prevent an allergic reaction. Some mildly allergic children can eat well-cooked eggs without experiencing any symptoms. Other children can have severe allergic reactions to even well-cooked eggs. In general, patients with egg allergies should avoid eggs until they reach school age.

Influenza vaccines are grown on egg embryos and may contain a small amount of egg protein. Individuals with egg allergies should be tested with the vaccine prior to vaccination. If test results are negative, the vaccine can be administered safely. If the test results are positive, your allergist need assess the benefits and risks of vaccination. If necessary, a split dose of vaccine may be administered cautiously for some patients.

Another type of food allergy is wheat, though it is not as common as other food allergies. Four specific groups of proteins (albumin, globulin, gliadin, gluten) cause wheat allergies. However, most children will eventually outgrow it.

Gluten intolerance, also called celiac disease, and wheat allergies are two distinctly different conditions. Celiac disease is an autoimmune disorder, not a food allergy, and is much more common than wheat allergy. Those with celiac disease do not lose their sensitivity to gluten. Therefore, they require a life-long restriction from wheat and other grains containing gluten, such as rye, oats and barley. Yet, an individual with a wheat allergy needs only to avoid wheat, not other grains.

Typically, celiac disease symptoms manifest themselves at 6 to 24 months of age, following the introduction of cereal into the diet. Symptoms include poor absorption of nutrients by the intestines, impaired growth, abnormal stools, abdominal distention, poor appetite, or irritability. In adults, the symptoms may be quite varied from severe weight loss and diarrhea to subtle abdominal complaints.

Wheat allergies and celiac disease are two separate conditions requiring unique treatment options presenting different outcomes. Obtaining an accurate diagnosis cannot be overemphasized.

Seafood can cause severe allergic reaction

Most cases of food allergies occur when someone with a genetic predisposition produced specific antibodies to the certain protein of a particular food. When these antibodies react to a specific protein, the release of chemicals from cells is triggered. Allergic symptoms include hives, swelling of the lips and tongue, trouble breathing, a drop in blood pressure, and even loss of consciousness. It can appear from within minutes to several hours after a person has eaten the food to which he or she is allergic. 

Although all foods can cause an allergy, peanuts, tree nuts, fish, shellfish, eggs, soy, milk, and wheat account for 90 percent of all food allergies. Peanuts are the leading cause of severe allergic reactions, followed by shellfish, fish, tree nuts, and eggs.

Seafood allergy generally develops in late childhood and is usually long. Raw fish tends to be more allergenic than cooked fish. Occasionally, cooking with intense heat can partially or completely destroy the triggering allergen.  This may explain why some patients who are allergic to fresh fish are able to tolerate canned salmon or tuna. People with extreme sensitivity can suffer a severe allergic reaction from trace amounts of seafood or even merely exposure to fumes of cooking seafood.

With shellfish, the crustacean group (including shrimp, crab, crayfish, and lobster) is most likely to cause an allergic reaction. Allergies to the mollusk group (including clam, oyster, abalone, mussel, scallop, squid, octopus, and escargot) are less common. Another seafood group consisting scaly fish (including salmon, cod, snapper, mackerel, tuna, grouper, flounder, halibut, trout, and sardines) can also cause food allergies.

It has been estimated that if a person is allergic to a fish, they have a 50 percent chance of being allergic to at least one other species of fish.  Furthermore, if they are allergic to shellfish, they have a 75 percent chance of allergic to another type of shellfish. However, in general, people suffering an allergy to one seafood group can tolerate another seafood group. There appears to be no cross-reaction between fish and shellfish, but simultaneous allergy is possible. Testing different seafood is the best way to establish accurate diagnosis.

The only "cure" for shellfish or fish allergies is to avoid the food groups. Read labels of every food you eat. Reread the labels each time you purchase a product, because manufacturing processes constantly change.  The principal treatment of acute severe allergic reaction is epinephrine. People with seafood allergies should carry self-injection devices such as an EpiPen with them at all times. After epinephrine is administered, they should be observed for four to eight hours at a medical facility and receive additional treatment, if necessary.