Upper Respiratory Tract Infection (The Common Cold)

Introduction

The common cold is the most frequent human illness and the single biggest driver of winter primary care consultations and inappropriate antibiotic prescribing. It is caused by a viral infection of the upper respiratory tract - predominantly the nose, throat and sinuses - and is entirely self-limiting in the vast majority of otherwise healthy people.¹

The main clinical tasks are managing symptoms appropriately without antibiotics, being able to distinguish a cold from influenza, COVID-19 and allergic rhinitis, and recognising the point at which a straightforward cold has been complicated by a secondary bacterial infection such as otitis media, sinusitis or pneumonia - each covered in more detail in their own articles.

Aetiology

Rhinovirus is the most common cause, responsible for a large majority of colds, followed by coronaviruses (the seasonal, non-SARS-CoV-2 strains), respiratory syncytial virus (RSV), parainfluenza virus, and adenovirus. Influenza and SARS-CoV-2 can also cause a cold-like illness but more typically produce a more severe systemic picture.¹

Transmission is via respiratory droplets and direct contact with contaminated surfaces, with the virus entering through the nasal or conjunctival mucosa. Incubation is short, typically 1-3 days, and viral shedding (and hence infectivity) is highest in the first 2-3 days of symptoms.

Clinical features and natural history

Typical symptoms are nasal congestion and discharge (initially clear, often becoming thicker and discoloured as the illness progresses - this is a normal part of the immune response and does not itself indicate bacterial infection), sore throat, sneezing, cough, and mild fever with general malaise.¹

Symptoms typically peak around day 2-3 and gradually improve, with most people feeling substantially better by day 7-10. Cough is often the last symptom to resolve and can reasonably persist for up to 3 weeks without indicating a complication or an alternative diagnosis.

Assessment

Assessment is largely about confirming a benign self-limiting illness and identifying any features that suggest a complication or an alternative diagnosis. Ask specifically about breathlessness, chest pain, ear pain, facial pain, and whether symptoms have improved and then worsened again ("double sickening"), and consider risk factors for a more severe course: extremes of age, pregnancy, immunosuppression, and chronic respiratory or cardiac disease.¹

Examination is usually unremarkable beyond nasal congestion/discharge and mild pharyngeal erythema. Chest auscultation and observations (respiratory rate, oxygen saturation, temperature) are useful to exclude a lower respiratory tract complication in anyone who seems more unwell than expected.

Management

Management is entirely supportive: simple analgesia and antipyretics (paracetamol, ibuprofen), adequate fluid intake, and rest. Decongestants can be used short term (no more than 5-7 days) for troublesome nasal congestion, but prolonged use risks rebound congestion (rhinitis medicamentosa). Simple cough remedies or honey (in adults and children over 1 year) provide modest symptomatic relief for cough.¹

Antivirals (e.g. oseltamivir for influenza) are not used for the common cold, and are reserved for confirmed or suspected influenza in patients at high risk of complications, started within 48 hours of symptom onset. General advice on hand hygiene, using tissues, and staying away from vulnerable contacts while symptomatic helps reduce transmission.

Complications

Complications result from secondary bacterial infection or from exacerbation of an underlying condition, and each has its own dedicated management approach covered elsewhere on this site:¹

• Acute otitis media: particularly in young children, from eustachian tube dysfunction during the cold
• Acute rhinosinusitis: persistent or worsening facial pain and discharge beyond 10 days
• Exacerbation of asthma or COPD: viral URTIs are the most common trigger for exacerbations of both conditions
• Lower respiratory tract infection/pneumonia: uncommon in healthy adults but a more significant risk in the very young, elderly, or immunocompromised
• Secondary bacterial pharyngitis/tonsillitis: covered separately

Red flags

Prognosis

The common cold is almost always self-limiting, with most adults and children recovering fully within 7-10 days without any specific treatment or lasting effect. Recurrent colds, particularly in young children who are frequently exposed to new viruses at nursery or school, are normal and do not in themselves indicate an immune deficiency or other underlying problem.¹