Food Allergy VS Food Intolerance: What's the difference between the two?

Many people are allergic or intolerant to certain foods.  As some of the signs of food allergy and food intolerance are similar, many people either get confused between the two or think that they are the same. Most of the time it is intolerance and not an allergy. Speaking of food allergy, the same causes an immune system reaction that affects different organs. There are several signs of it including nausea, stomach pain, diarrhoea and vomiting (which are quite similar to intolerance). 

Aside from these, rash, hives, or itchy skin, shortness of breath, chest pain, a sudden drop in blood pressure, trouble swallowing or breathing are some other and important signs of allergy.  In some cases, food allergy can be very severe or life-threatening. And you could be at risk for anaphylaxis, a life-threatening reaction. And that's why many allergic people carry emergency epinephrine shot for emergency self-treatment. 

On the other hand, food intolerance is generally less serious and often limited to digestive issues. If you have a food intolerance, then there are chances that you may be able to eat that food in small amounts. For example, if you have lactose intolerance, you may be able to drink lactose-free milk or take lactase enzyme pills for digestion. Common signs are gas, cramps, or bloating, heartburn, headaches, Irritability or nervousness among others. 

Absence of an enzyme needed to fully digest food, Irritable bowel syndrome aka IBS, sensitivity to the sugars naturally found in certain foods, recurring stress or psychological factors are some of the causes of food intolerance. Your doctor may recommend you to follow steps to aid the digestion of certain foods or treat the main cause of the reaction.

Difference between the two: 

Food allergy:

It happens when your immune system mistakes something in food as harmful and attacks it

Allergy can affect your whole body, not just your abdomen

Usually happens suddenly

Can be triggered by even a small amount

Can be life-threatening

Food intolerance:

Certain foods irritate your stomach or your body can't properly digest it

Not immune-mediated and the reaction is triggered by the digestive system

They are more common than food allergy

Happens gradually

The signs or reaction may happen when you eat a lot of the food

May happen when you eat that food often

Not fatal

Common food allergies: 

Peanuts, Tree nuts such as walnuts, pecans and almonds, fish, milk, eggs, soy and wheat.

Common food intolerances:

Lactose intolerance is the most common, reactions to food additives or preservatives like sulfites, MSG, or artificial color and gluten-rich foods, sensitivity to caffeine or other chemicals.

Note: If you are experiencing reactions in your body after eating a particular food, then check with your doctor to determine whether you have a food intolerance or a food allergy.