Nut Allergy: Symptoms, Risks, and First Aid Response

A nut allergy occurs when the immune system overreacts to proteins found in peanuts or tree nuts. During an initial exposure, the immune system becomes sensitized, but symptoms may not appear right away. It is often during subsequent exposure that a noticeable allergic reaction occurs.

Many children and adults with nut allergies can react to very small amounts, and in some cases even trace exposure—meaning direct consumption of nuts is not always required for a reaction to happen.

Signs and Symptoms of a Nut Allergy

Allergic reactions to nuts can range from mild to severe and life-threatening. Symptoms typically begin within minutes to one hour after exposure. Reactions that start more than four hours later are unlikely to be due to a nut allergy.

Mild Allergic Reaction

Symptoms may include:

• Tingling or itching of the lips and mouth

• Nausea or feeling sick

• Facial or lip swelling

• Hives or itchy skin

• Cramping or colicky abdominal pain

• Sensation of throat tightness

Even mild symptoms should be monitored closely, as reactions can progress quickly.

Severe Allergic Reaction (Anaphylaxis)

A severe nut allergy reaction, known as anaphylaxis, includes all of the above symptoms plus one or more of the following:

• Difficulty breathing or wheezing
• Swelling of the tongue or throat
• Rapid heartbeat
• Low blood pressure
• Widespread skin redness
• Dizziness or collapse
• A sense of impending doom

Anaphylaxis is a medical emergency.

What to Do During a Nut Allergy Reaction

Mild Reaction

• Administer an oral antihistamine as soon as possible
• Monitor symptoms closely
• Seek medical care if symptoms worsen or new symptoms appear

Antihistamines usually take 15–30 minutes to take effect and do not treat anaphylaxis.

Severe Reaction (Anaphylaxis)

• Administer epinephrine immediately using an auto-injector if available
• Call 911 or local emergency services right away
• Lay the person flat or allow them to sit if breathing is difficult
• A second dose of epinephrine may be required if symptoms persist

Individuals experiencing anaphylaxis often require hospital observation, even if symptoms improve.

Important First Aid & Training Notice

Nut allergies are unpredictable, and even individuals with a history of mild reactions can experience severe anaphylaxis without warning. Knowing how to recognize allergic reactions and use an epinephrine auto-injector correctly is a critical life-saving skill.

This information is provided for educational purposes only and is not a substitute for medical advice or emergency care. Anyone experiencing a severe allergic reaction should receive immediate medical attention.

St. Mark James Training, Canada’s largest 100% Canadian-owned and operated first aid and CPR training provider, offers nationally recognized courses that teach participants how to respond to allergic reactions, including anaphylaxis, in workplaces, schools, childcare settings, and public environments across Canada.