What are the causes and treatments of post-viral cough (post infectious cough)?

From the Guidelines

Post-viral coughs typically resolve within 3-8 weeks without specific treatment, and the optimal management approach involves a step-wise strategy to alleviate symptoms and improve quality of life. To manage post-viral cough, consider the following:

• Try over-the-counter cough suppressants containing dextromethorphan (such as Robitussin DM) for nighttime relief, or guaifenesin (Mucinex) to thin mucus during the day 1.
• Honey (1-2 teaspoons) can soothe throat irritation, while staying hydrated with warm fluids helps loosen mucus.
• Using a humidifier at night and avoiding irritants like smoke can reduce cough triggers.
• For adult patients with postinfectious cough, not due to bacterial sinusitis or early on in a Bordetella pertussis infection, consider a trial of inhaled ipratropium as it may attenuate the cough 1.
• In patients with postinfectious cough, when the cough adversely affects the patient’s quality of life and when cough persists despite use of inhaled ipratropium, consider the use of inhaled corticosteroids 1.
• If your cough persists beyond 8 weeks, worsens, or is accompanied by fever, shortness of breath, or blood in sputum, consult a healthcare provider as this could indicate a secondary infection or another condition.
• Central acting antitussive agents such as codeine and dextromethorphan should be considered when other measures fail 1.
• Therapy with antibiotics has no role, as the cause is not bacterial infection 1.

From the FDA Drug Label

Helps loosen phlegm (mucus) and thin bronchial secretions to make coughs more productive. temporarily relieves: cough due to minor throat and bronchial irritation as may occur with a cold or inhaled irritants cough lasts more than 7 days, cough comes back, or occurs with fever, rash or headache that lasts.

The post viral cough can be relieved with guaifenesin (PO) 2 or codeine (PO) 3 as they help loosen phlegm and thin bronchial secretions. However, dextromethorphan (PO) 4 should be used with caution and under the guidance of a doctor, especially if the cough persists for more than 7 days or is accompanied by other symptoms such as fever, rash, or headache.

• Key considerations for post viral cough treatment include:
  • Monitoring the duration and severity of the cough
  • Being aware of potential interactions with other medications, such as MAOIs
  • Seeking medical attention if the cough persists or is accompanied by concerning symptoms.

From the Research

Definition and Prevalence of Post-Viral Cough

• Post-viral cough is a type of cough originating from upper respiratory tract infections that persists after the infection is resolved 5.
• It can be disabling in daily activities, with substantial impact on physical and psychosocial health, leading to impaired quality of life and increased health care costs 6.
• Post-viral cough is a common reason for patients to visit general practices, and it is defined as lasting 3 to 8 weeks after an upper respiratory tract infection 6.

Treatment Options for Post-Viral Cough

• A combination of a β-agonist and an anticholinergic agent can effectively reduce post-viral cough, and can thus represent a valid option for this type of cough 5.
• Oral corticosteroids may provide patient-relevant benefit without relevant harm, and a randomized controlled trial is being conducted to evaluate their effectiveness for post-infectious cough 6.
• Inhaled corticosteroids can be given a trial to suppress airway inflammation in patients with post-COVID-19 cough who do not respond to early symptomatic treatment 7.
• Non-pharmacological remedies, such as honey, glycerol, and herbal agents, may be effective in relieving post-viral acute cough, but further rigorous studies are needed to confirm their efficacy and safety 8.

Pathophysiology of Post-Viral Cough

• Augmented cough reflex sensitivity is responsible for persistent cough after acute viral upper respiratory infection (URI) 7.
• The heightened cough reflex associated with SARS-CoV2 induces neurotropism, neuroinflammation, and neuroimmunomodulation via the vagal sensory nerves 7.
• Therapies for post-COVID-19 cough aim at the suppression of cough reflex 7.