What causes the common cold?

Many different viruses can cause a cold. After entering the nose, mouth or eyes, a virus can inflame the upper airways. This produces a blocked or runny nose, sneezing, sore throat, cough and sometimes a mild fever or tiredness. Symptoms can overlap with sinusitis, acute bronchitis, croup, or a middle-ear infection, particularly when symptoms change or persist.

Cold viruses spread more readily when people are close together indoors. Touching the face after contact with respiratory secretions can also transfer infection. Antibiotics do not treat viruses, although a clinician may reassess someone whose symptoms suggest a different or additional infection.

Rest, drink enough to avoid dehydration, and use warm fluids or honey for a cough when suitable; honey is not for babies under one year. Saline nasal drops or spray may ease a blocked nose. Wash hands, cover coughs and sneezes, and avoid sharing cups or towels while unwell. Ask a pharmacist before giving cold medicines to a child or combining products, since ingredients can overlap.

Get medical advice for breathing difficulty, chest pain, bluish lips, confusion, dehydration, a severe headache, or a fever that is concerning or not settling. Seek prompt assessment for a child with a barking cough or noisy breathing, an infant who is feeding poorly, or ear pain with discharge. Review is also sensible when symptoms worsen after initial improvement or do not follow a typical recovery.

Ask which symptoms fit a cold, whether another infection needs checking, which medicines are safe for your age or pregnancy, and how to protect vulnerable household members.