Allergy signs and symptoms

Allergy can affect almost any part of the body, inside and out, making a person feel sick in many different ways. What happens inside the body to cause an allergic reaction is exactly the same as what happens to cause an anaphylactic reaction; the difference is the severity of the symptoms.

For example, a mild allergic reaction to a food trigger might be tingling of the lips, whereas a severe reaction would be swelling of the tongue. A moderate allergic reaction to an insect sting could be itching, reddening, swelling and pain around the area the sting occurred, whereas a severe reaction might involve a widespread rash, dizziness and difficulty breathing. It’s like a scale, with symptoms becoming a little bit worse at each step until they are severe and are identified as anaphylaxis.

The allergy spectrum

Allergy symptoms can be mild, moderate or severe. Only some people will experience the very severe symptoms of anaphylaxis.

Allergy continuum

Possible symptoms of allergy

Telltale symptoms of anaphylaxis include:

• Difficult/noisy breathing
• Swelling of tongue
• Swelling/tightness in throat
• Difficulty talking and/or hoarse voice
• Wheeze or persistent cough
• Persistent dizziness or collapse
• Becoming pale and floppy (young children)


Where symptoms occur Mild-to-moderate symptoms Anaphylaxis
Central nervous and/or cardiovascular system

Dizziness, headaches

Persistent dizziness; fainting; in children, being pale or floppy; chest pain; weak pulse


Tingling or mild swelling of the face, lips, or eyes

Swelling of the tongue


Runny nose; cough

Difficult and/or noisy breathing; throat swelling or tightness; Difficulty talking; wheeze; persistent cough

Gastrointestinal system

nausea; stomach/abdominal pain; vomiting

Stomach/abdominal pain or vomiting in a person with an insect sting allergy


Hives; welts; itching; body redness

Stomach/abdominal pain or vomiting in a person with an insect sting allergy


These are just some of the symptoms that may be caused by an allergy or during an anaphylactic reaction. A person may have one, some, or all of these symptoms. Or, they may have different symptoms altogether. Symptoms can also change over time, so just because you have never had a severe reaction before, it does not mean you won’t have one in the future.

Warning signs

Sometimes, before an anaphylactic reaction occurs, a person experiences milder symptoms. These may include tingling of the skin or nausea. These early symptoms can be a useful warning that exposure to a trigger has occurred, and that treatment may be needed.

Speak to your doctor about the signs and symptoms of anaphylaxis, and learn the warning signs for you or your child.