Common Cold Viruses: Causative Agents and Treatment
Viral Etiology
Over 200 different viruses cause the common cold, with rhinoviruses being the dominant pathogen responsible for 30-80% of cases. 1
The major viral culprits include:
- Rhinoviruses: Account for 30-80% of common colds and represent the most important viral group, with at least 89 different antigenic types 1, 2
- Human coronaviruses: Cause approximately 15% of colds 1
- Respiratory syncytial virus (RSV): Responsible for 10-15% of cases 1
- Adenoviruses: Cause about 5% of colds 1
- Influenza and parainfluenza viruses: Also implicated in common cold syndrome 1
- Enteroviruses: Additional but less common causes 1
Pathophysiology and Transmission
These viruses spread through multiple routes including airborne droplets from coughing/sneezing, direct hand contact, and contact with contaminated surfaces (utensils, towels, keyboards, toys, telephones). 1 Direct hand contact is the most efficient transmission route, making handwashing the best prevention method. 1
The viral infection triggers an inflammatory cascade rather than causing direct tissue destruction. Rhinoviruses attach to ICAM-1 receptors on posterior nasopharyngeal epithelial cells, upregulating histamine, bradykinin, and cytokines (interleukin-1, -6, -8, TNF-α, leukotriene C4). 1 This inflammatory response—not epithelial destruction—generates the characteristic symptoms of nasal congestion, rhinorrhea, sore throat, cough, low-grade fever, headache, and malaise. 1
Treatment Approach
Antibiotics should never be prescribed for the common cold as they provide no benefit and increase risk of adverse effects. 1 This is critical: 30% of common cold visits result in inappropriate antibiotic prescriptions, contributing to antimicrobial resistance. 1
Effective Symptomatic Treatments for Adults:
- First-generation antihistamine plus decongestant combinations: 1 in 4 patients experiences significant symptom relief 1, 3
- Zinc (acetate or gluconate): Reduces symptom duration if started within 24 hours of onset, though may cause nausea and bad taste 1, 4
- Intranasal ipratropium bromide: Effective for rhinorrhea 1, 3
- NSAIDs (like naproxen): Provide symptomatic relief 3, 4
- Pseudoephedrine or phenylephrine: Modest benefit for nasal congestion 4
Effective Treatments for Children:
Over-the-counter cough and cold medications should NOT be used in children younger than 4 years due to potential harm without benefit. 1, 4
Safe and effective pediatric options include:
- Honey (for children ≥1 year old): Proven effective 5
- Nasal saline irrigation: Safe and effective 5
- Intranasal ipratropium: For cough 5
- Topical ointments containing camphor, menthol, and eucalyptus oils 5
- Acetylcysteine: Established benefit 5
Ineffective Treatments to Avoid:
- Vitamin C and echinacea: No evidence of benefit 1
- Inhaled corticosteroids: Ineffective 4
- Oral prednisolone: No benefit 4
- Antibiotics: Never indicated for uncomplicated viral colds 1, 3
Clinical Course and Follow-Up
Symptoms typically last up to 2 weeks, and patients should be counseled that this duration is normal. 1 Advise follow-up if symptoms worsen or exceed expected recovery time. 1 When cough persists beyond 3 weeks after viral infection, consider postinfectious cough (upper airway cough syndrome). 1, 3
A critical pitfall: Approximately 85-98% of primary care physicians prescribe antibiotics for clinically suspected rhinosinusitis, but most cases are viral and do not require antibiotics. 1 The presence of colored nasal secretions or abnormalities on sinus imaging during a cold does not indicate bacterial infection—these are frequently due to the viral infection itself. 1