Difference Between Cold and Allergies

Cold vs Allergies | Allergy vs Common Cold (Acute Coryza) Cause, Symptoms, Diagnosis, and Management

Once a patient comes with features of Runny nose, nasal congestion and cough, it is a bit of confusion whether these symptoms are caused by cold or by allergy since these two conditions share some common characteristics. It is the responsibility of the doctor to decide which of the condition in more favor of that patient since the management options are different in these two conditions. So it is important to identify the differences between cold and allergy and this article would be helpful to differentiate them.


Common cold also known as acute coryza is a viral respiratory tract infection mostly caused by rhinoviruses. The transmission of the disease is by air borne droplets, and the disease lasts for 1-3 weeks. Cold is contagious.

Symptoms take a few days to appear after the viral infection. Patients usually presents with a burning sensation at the back of the nose soon followed by nasal stuffiness, rhinorrhoea, sore throat and sneezing. Patient may run low grade fever. In pure viral infection, nasal discharge is watery but may become mucopurulent when bacterial infection supervenes. Runny nose seen in allergic rhinitis may cause diagnostic confusion, but it is usually accompanied by other symptoms such as red eyes, itchiness and skin manifestations.

The disease is usually self limiting and resolves spontaneously after 1-3 weeks. Bed rest is advised, and plenty of fluids are encouraged. Antihistamines, nasal decongestants, analgesics, and antibiotics are considered as supportive measures depending on the symptoms.

Occasionally patients may develop complications such as sinusitis, pharyngitis, tonsillitis, bronchitis, pneumonia and otitis media.


An allergy is a hypersensitive reaction of the immune system to a particular allergen. The duration of the disease may be days to months, but it is as long as the person is exposed to that particular allergen.

Allergies may vary from mild hay fever to severe life threatening conditions. Symptoms can begin immediately after exposure to the allergen. Commonly seen symptoms are red eyes, itchiness, runny nose, eczema, hay fever or an asthma attack. In some people, severe allergies to medication or the environment, or dietary allergens may result in life-threatening conditions such as anaphylaxis. Fever is not a feature of allergies.

Skin hypersensitivity tests with the relevant antigen helps in making the diagnosis. Management of allergies includes reducing exposure to any identifiable etiological factor, use of anti histamines, steroids that modify the immune system in general and other supportive measures. Adrenalin is used to treat severe anaphylactic reactions. Immunotherapy is another treatment modality in which the desentisization or the hyposensitization is obtained.


What is the difference between cold and allergies?

• Common cold is usually resulted from viral respiratory tract infection, but allergy is a hypersensitivity reaction to a particular antigen.

• Cold usually lasts 1-3 weeks, but allergy can persists days to months, it can be as long as exposure to the allergen.

• Symptoms of cold take few days to develop after the viral infection, but allergic symptoms begin immediately after the exposure.

• Constitutional symptoms are more common with cold than allergy.

• Fever is never a feature of allergy.

• Itchiness, watery eyes usually accompanied with allergy rather than cold.

• Cold is usually self limiting but allergy needs interventions and treatment.

• Severe allergies are life threatening and has become a medical emergency.

• Cold is contagious but allergies are not.