Food allergies are abnormal immune system reactions to food. The reactions can be mild or acute. A food allergy that causes severe symptoms or even a life-threatening reaction is known as anaphylaxis. Food allergies affect an estimated 6 to 8 percent of children under age 3 and up to 3 percent of adults. They are more common in children than adults and male children are more commonly affected than females. Common foods that cause allergic reactions include cow’s milk, peanuts, eggs, shellfish, tree nuts, wheat, rice, and fruit.
Food Allergies and Food Intolerance
Food allergies and food intolerances are often considered the same by mistake. However, a food intolerance is much less severe than a food allergy. Real food allergies cause immune system reactions that affect numerous organs in the body. It can cause a range of symptoms. In contrast, food intolerance symptoms are generally less serious and often limited to digestive problems that do not involve the immune system.
Causes of Food Allergy
When the immune system mistakenly identifies a specific food or a substance in food as something harmful, food allergies are induced. This causes a range of allergy signs and symptoms.
Symptoms of Food Allergy
- Tingling or itching of mouth, lips, tongue, throat, eyes, skin, or other areas
- Swelling of lips, tongue, eyelids, the whole face or other parts of the body
- Rashes, Hives or eczema
- Runny or congested nose
- Wheezing or breathing trouble
- Hoarse voice
- Swallowing difficulty
- Abdominal pain, diarrhea, nausea or vomiting
- Dizziness, lightheadedness or fainting
In addition, Anaphylaxis may cause rapid pulse, a sudden drop in blood pressure and constriction and tightening of airways.
Most Common Allergens 
- Shellfish, such as shrimp, lobster and crab
- Peanuts
- Tree nuts, such as walnuts and pecans
- Fish
- Eggs
- Milk
- Wheat
Treatment
If the symptoms are serious it is recommended to consult a doctor. Treatments for food allergies include epinephrine, steroids, antihistamines, and desensitisation. After diagnosing and running tests, the doctor decides which treatment is best.