Allergies or cold? How to tell the difference

A boy sneezing

Frequent sneezing may make you think you have a cold. But sneezing can also be a symptom of a respiratory allergy. In other words, your sneezing may be caused by an allergic reaction to a substance in the air.

Allergies or cold?

It can be difficult to tell the difference between having a respiratory allergy and having a cold. Both share similar symptoms such as irritation and inflammation of the inside of your nose. Respiratory allergies and a cold can both cause sneezing and a runny, or stuffy nose. How can you tell if the symptoms you’re experiencing are caused by allergies or a cold?

In this article, we’re going to be discussing the key differences between having allergies and having a cold.

How to tell the difference between allergies and a cold

Most people will have experienced a common cold. But some of the symptoms of respiratory allergies are similar to those of a common cold. So how can you tell the difference between allergies and a cold?

There are some key signs you can look for:


Itchy nose or eyes
Colds Allergies



Color and texture of mucus
Colds Allergies

Can become yellowish or greenish and quite thick

Usually clear and watery

Sore Throat
Colds Allergies



Achy muscles and pain
Colds Allergies


Not usually

Raised temperature or fever
Colds Allergies


Very unlikely


How long the symptoms last
Colds Allergies

Usually about 1 week.
Sometimes as long as 2 or 3 weeks.

Last as long as you're exposed to your triggers. For example, if you react to pollen, symptoms can last many weeks during the season.

When symptoms appear
Colds Allergies

Gradually over a few days.

Soon after being exposed to the allergen.

Symptoms only show in certain situations
Colds Allergies

Once you have a cold you have symptoms no matter where you are.

If you 're experiencing symptoms when you're outside, in a specific place or have contact with an animal, then it might be allergies.

A closer look at allergies and colds

To help you understand the difference between allergies and a cold better, let’s take a look at what allergies are and what causes a cold.

Allergies vs cold: What are allergies?

Allergies are very common around the world and can affect people from all walks of life. Having allergies may be a nuisance, restrictive and sometimes even frightening. But what exactly is allergy?  

When you have an allergic reaction it’s because your immune system has mistakenly responded to something that’s normally harmless.

Quote Image

Allergies and a cold share many of the same symptoms. But a cold is caused by a virus, while allergies are triggered by an overactive immune system.

Substances that trigger an allergic reaction are called allergens. Typical types of airborne allergens that can cause respiratory allergy are:

In most people, these substances don’t cause any issues. But in people with allergies, your immune system reacts to a false alarm. Your immune system identifies the substance as a threat and takes exaggerated action to defend your body.

9 symptoms of respiratory allergies

Airborne allergens typically cause cold-like symptoms so it can be tricky to know if it’s allergies or a cold.

We’ve created a list of the typical symptoms you can expect from an allergic reaction to airborne allergens. These symptoms usually occur shortly after being exposed to the allergen.

  • Stuffy nose (nasal congestion)
  • Runny nose, usually with clear fluid
  • Sneezing
  • Itchy nose
  • Itchy, red or watery eyes
  • Post-nasal drip (the feeling of mucus moving down the back of your throat)
  • Cough
  • Tight chest or wheezing
  • Sinus inflammation/pain

If you have allergies, you can have any combination of the symptoms on our list. And you may experience your symptoms differently from other people with allergies.

Young woman considering allergy testing

Allergy testing: what is it?

Are allergies contagious?

You can’t catch allergies in the same way you can catch a cold. Allergies are an overreactive response from your immune system and aren’t contagious.

Allergy is a complex condition and it’s still not clear why some people develop allergies and others don’t. We do know that allergies may run in families. Many people with allergies have other members of their family who are also affected by allergies. But this isn’t a hard and fast rule.

Allergies vs cold: What’s a cold then?

The cold is one of the most common respiratory illnesses in humans. A cold is caused by a virus and unlike allergies, colds are contagious and easily passed on to other people. There are more than 200 specific viruses that can cause the common cold.

Colds are easily spread

Colds are spread by droplets from coughs or sneezes from someone who is infected. So when we touch the infected hands or surfaces and then touch our own face, eyes or nose, the virus can start a new infection. It’s also possible to catch a cold by breathing in particles after the person with the infection has coughed or sneezed.

9 symptoms of a common cold

Let’s have a look at the symptoms of the common cold to better understand the difference between allergies and a cold. An important difference between the symptoms of a cold and the symptoms of allergies is how quickly they develop. Cold symptoms appear gradually and can include any of the following:

  • Sore throat
  • Stuffy nose (nasal congestion)
  • Runny nose
  • Sneezing
  • Hoarseness
  • Cough
  • Raised temperature
  • Achy muscles
  • Headaches

Talk to your doctor if you think you may have allergies

If you think your symptoms might be caused by allergies, we recommend you make an appointment to speak to your doctor about it. Your doctor will be able to help you find out if it really is allergies or a cold. And if you have allergies, your doctor will be able to help you discover what your specific triggers are.

Tell your doctor about your symptoms, such as when you experience them, how long they last and if you are aware of what might be triggering them. If it’s obvious what’s causing them, your doctor can offer advice and discuss treatment options. But if it’s not clear and your symptoms are having an impact on your life, you may be referred for allergy testing.

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