You can have a food allergy, and eat it too

In his presentation, Dr. Bahna noted not only can certain parts of food be safe to eat for some food allergy sufferers, but there are some substitutes that can be eaten as well.

"Just because someone is allergic to cow's milk, doesn't mean they are allergic to milk from all other animals," said Dr. Bahna. "Some sufferers might have to avoid several foods, which can be difficult and cause malnutrition. But there are substitutes that can be eaten without any side effects."

Some food sensitivities may also predict other food allergies. Different types of fruits and fish can often have substantial cross-reactivity, meaning there may be several types that need to be avoided.

Rosaceae fruits, which include apple, apricot, almond, peach, pear, plum and strawberry, showcase this cross-reactivity. Crustaceans, such as shrimp and lobster, or molluscs like clam and squid can also have this cross-reactivity. But it's more unlikely that someone allergic to shrimp is also allergic to squid.

"While many food allergic individuals find they can eat certain parts of food or substitutes, this isn't a one size fits all approach," said Dr. Bahna. "Allergy manifests in everyone differently. If you have a food allergy, evaluation by a board-certified allergist can identify the exact foods that you should avoid and the substitute foods that you can safely eat."

Allergy skin testing or blood testing are good screening procedures for food allergy. Allergists often confirm the suspected foods by performing oral food challenges. During this test, patients are fed tiny amounts of the suspected allergy-causing food in increasing doses under strict supervision by an allergist.

Although there is no cure for food allergies at present, some sufferers may outgrow their allergy over time. Milk allergy is commonly outgrown in childhood, while a peanut or shellfish allergy usually lasts for many years or for a lifetime.