Common cold or allergy: how to tell the difference

A common cold often begins after contact with an infected person and may bring a sore throat, cough, tiredness, or a fever. Symptoms usually change as the illness settles. An allergy may cause repeated sneezing, an itchy nose or eyes, watery discharge, or a blocked nose after exposure to pollen, dust, mould, or an animal. It does not spread from person to person.

Symptoms can overlap, and a person may have both conditions. Thick mucus does not prove that an infection is present, and an itchy nose does not exclude a cold. A clinician may use the timing, triggers, examination, and symptom pattern to guide the assessment.

For cold symptoms, rest, drink enough fluids, and use saline to ease a blocked nose. For suspected allergies, reduce exposure to the trigger, keep windows closed during high-pollen periods if that helps, and wash after outdoor exposure. Ask a pharmacist or clinician before using an antihistamine or nasal spray, particularly for a child, pregnancy, or another medical condition. Avoid antibiotics unless prescribed for a diagnosed bacterial problem.

Seek medical advice when symptoms persist, repeatedly return after a particular exposure, disturb sleep, or make breathing difficult. Get urgent help for swelling of the lips or tongue, throat tightness, wheezing, faintness, or severe breathing difficulty, which can signal a serious allergic reaction. Fever with a child who looks very unwell, dehydration, or worsening cough also needs prompt assessment.

Ask what pattern best fits your symptoms, whether an allergy trigger is likely, and which treatments are suitable for your age and health history. Bring a note of exposures, symptom timing, fever, and any products already tried.