What is a food allergy?

A food allergy happens when your immune system reacts to a food as if it were harmful. Even a small amount of that food can trigger a reaction. This is different from food intolerance, which affects digestion but not the immune system.

Food allergies can range from mild to severe and may affect the skin, stomach, breathing, or heart.

Common causes:

• The immune system reacting to specific food proteins
• Frequent triggers include milk, eggs, wheat, soy, peanuts, tree nuts, fish, and shellfish
• Some infants may develop delayed reactions, such as FPIES, often linked to milk or grains

Symptoms

Food allergy symptoms can appear quickly—often within minutes of eating.

Common symptoms include:

• Hives or itchy skin
• Swelling of the lips, face, or tongue
• Stomach pain, nausea, or vomiting
• Diarrhea
• Coughing, wheezing, or trouble breathing
• Dizziness or feeling faint

In more serious cases, a life-threatening reaction called anaphylaxis can occur. This may cause severe breathing problems, throat swelling, or a sudden drop in blood pressure.

How is it diagnosed?

Your provider will start by asking about your symptoms and medical history. A physical exam helps rule out other conditions.

To confirm a food allergy, testing may include:

• Skin prick testing
• Blood tests to measure immune response
• Carefully supervised food challenges
• Temporary elimination of certain foods

These steps help identify which foods are causing the reaction.

How is it treated?

The most important step in managing a food allergy is avoiding the food that triggers symptoms.

Treatment options include:

• Reading labels and asking about ingredients when eating out
• Carrying an epinephrine auto-injector for emergencies
• Using medications to relieve mild symptoms
• Oral immunotherapy in select cases to reduce sensitivity

If a severe reaction occurs, epinephrine should be used right away, followed by emergency care.

Living with a food allergy often requires planning, but with the right steps, people can continue to enjoy safe and balanced meals.