Food Allergy

Understanding Food Allergies: Symptoms, Causes, and Testing

A food allergy occurs when the immune system reacts abnormally to certain foods. Individuals with atopic syndrome—a combination of allergic conditions such as allergic rhinitis, conjunctivitis, eczema, and asthma—are more likely to develop food allergies. Since this syndrome has a strong genetic component, a family history of allergies can indicate a higher risk.

Who Can Develop Food Allergies?

Food allergy symptoms are most commonly seen in babies and children, but they can develop at any age. Surprisingly, even foods that have been safely consumed for years can suddenly trigger an allergic reaction.

Common Food Allergens in India

While any food can potentially cause an allergic reaction, the following eight foods account for approximately 90% of all food allergies in India:

  • Eggs
  • Milk
  • Peanuts
  • Tree nuts
  • Fish
  • Shellfish
  • Wheat
  • Soy

Additionally, sesame and mustard seeds—commonly found in Indian cuisine—are also significant food allergens.

Symptoms of a Food Allergy

Food allergies can affect multiple systems in the body, including the skin, gastrointestinal tract, cardiovascular system, and respiratory system. Symptoms may appear as:

  • Digestive issues: Vomiting, stomach cramps
  • Skin reactions: Hives, swelling, pale or blue-colored skin
  • Respiratory issues: Shortness of breath, wheezing, hoarseness, difficulty swallowing
  • Circulatory symptoms: Weak pulse, dizziness, fainting, circulatory collapse (shock)

The Challenge of Food Allergy Testing

Food allergy testing is complex and often misunderstood. While skin prick tests and blood tests can detect allergies, they sometimes yield false positives—showing an allergy when none actually exists. This can lead to unnecessary dietary restrictions.

However, many children outgrow allergies to milk, eggs, wheat, and soy over time. In contrast, allergies to peanuts, tree nuts, and seafood tend to persist into adulthood. When someone outgrows an allergy, it is referred to as developing tolerance to that particular food.