At a glance, the symptoms of a cold and allergy appear similar. You’ll have a runny nose, nasal congestion, coughing, sneezing, post-nasal drip, conjunctivitis and a sore throat. But there are distinct differences, particularly when it comes to cause and treatment plan. 

So how do you know if you’ve caught a cold or if it’s just your allergies acting up? 

Duration of symptoms

Cold symptoms typically last between seven and 10 days, while allergy symptoms can last much longer – several weeks in fact if the allergen remains in the air. 

Allergy symptoms, however, usually come and go during a particular season or environment. If your nose suddenly starts to run while you’re out hiking, you’re probably displaying symptoms of an allergy to the grass you’re walking through. 

Learn to tell the difference

Symptoms of a cold typically develop over a few days, starting with a phase of sneezing and lots of clear nasal secretions. This is usually followed by a thick nasal secretion phase and blocked nose, which is often accompanied by tiredness, sore throat, fatigue and fever. 

Nasal allergies tend to follow a similar pattern in different individuals − for example you will start sneezing. Symptoms will change depending on what allergen you’ve been exposed to − for example being outdoors, time of year, pet exposure and so on.

Ask yourself these questions: 

1. Did your symptoms appear suddenly? 
Cold symptoms usually appear gradually over a few days, while allergy symptoms occur suddenly. 

2. How long have you had symptoms? 
Cold symptoms generally last a week or two, while an allergy will last for as long as you’re exposed to allergen. 

3. Are your symptoms predictable for the time of year that they appear? 
If symptoms appear like clockwork at the same time every year, you have an allergy. 

Identify the cause

More than 200 subtypes of virus (e.g. rhinovirus or coronavirus) can cause a cold, which is transmitted through droplets in the air from coughing and sneezing. Colds are more common during winter but you can catch them at any time during the year. Allergies are caused by allergens that affect your immune system and are not contagious. 

Treatment plans

According to Associate Professor Jonathan Peter, head of the Allergology and Clinical Immunology division at UCT’s Department of Medicine and the Allergy Clinic at the UCT Lung Institute, untreated allergies can predispose an individual to increased colds. 

Your treatment plan for a cold will differ vastly from an allergy. Although there isn’t a cure for the common cold, Prof Peter suggests taking nasal decongestants for a few days to unblock the nose and flu tablets, which usually contain a mix of simple pain medicine for a headache and some caffeine to keep you going. 

If your symptoms worsen or linger past two weeks, see your doctor.

“When it comes to allergies, there are a number of approaches, you need to try and identify the triggering allergen(s),” he explains. “Avoiding the offending allergen(s) can help reduce will keep your symptoms under control. Intranasal steroids can help prevent further symptoms on allergen exposure. Antihistamines – nasal or tablets – also help.” 

See your doctor if you have ongoing symptoms without a known cause that are interfering with your work, social life and sleep. You may even consider immunotherapy, which can offer you a cure of certain allergies – ask you doctor for more information about this.

Read more: 

Stop believing these 10 allergy myths

Semen and other bizarre allergies

First aid for seasonal allergies

Mandy Freeman