State of the Art Pediatrics: Getting to the Bottom of That Chronic Cough

Column Author: Christopher Oermann, MD| Director, Cystic Fibrosis Center, Professor of Pediatrics, University of Missouri-Kansas City School of Medicine; Clinical Professor of Pediatrics, University of Kansas School of Medicine

Column Editor: Amita Amonker, MD, FAAP | Physician Advisor, Care Management and Utilization Review, Assistant Professor of Pediatrics, University of Missouri-Kansas City School of Medicine; Clinical Assistant Professor of Pediatrics, University of Kansas School of Medicine

Respiratory complaints are among the most common acute concerns in general pediatric practice. Cough, in particular, is a frequent symptom causing anxiety among parents. Most cough is secondary to acute respiratory infection and is self-limited. When cough becomes “abnormal” due to increased frequency, severity or duration, referral to pediatric pulmonary medicine may be indicated.¹ 

Among children, cough is often classified as acute (three weeks or less), prolonged/protracted (three to four weeks), or chronic (more than four weeks of daily cough). Most children will have eight to 12 acute respiratory tract infections per year with healthy intervals between infections. These children do not typically require evaluation by a pulmonologist. Prolonged postinfectious cough is seen with many respiratory tract infections and does not require referral unless the cough is productive or is associated with systemic signs or symptoms. 

The primary concern with protracted, productive cough after a respiratory infection is persistent bacterial bronchitis (PBB). PBB is defined as 1) presence of continuous daily cough of more than four weeks’ duration, 2) absence of signs or symptoms suggestive of a specific cause of cough, and 3) resolution of cough following two to four weeks of appropriate antibiotic therapy.² The pathogens involved are typical “respiratory bacteria,” including H. influenzae (28%-58%), S. pneumoniae (13%-58%) and M. catarrhalis (17%-59%). Although PBB is most common among preschool children (age 1-5 years), it has been reported in older children. Systemic signs and symptoms are generally lacking. Physical examination is often normal, though coarse airway crackles or wheezes may be present. Chest radiographs and laboratory studies are typically normal. Appropriate empiric management of PBB includes a minimum of two weeks of amoxicillin-clavulanate or a later-generation cephalosporin; three- to four-week courses are often prescribed by pediatric pulmonologists. If symptoms resolve, referral is not necessary. PBB may recur and referral is appropriate for recurrent episodes. 

In a study of chronic cough among 346 Australian children, asthma was the second most common cause of “chronic” cough.³ Although the cough associated with asthma is more accurately described as recurrent rather than chronic, some children with asthma, particularly preschool children, may have true chronic cough. A comprehensive discussion of asthma is beyond the scope of this article, but a few salient points are worth mentioning. Differentiating cough and wheeze associated with acute respiratory tract infection versus asthma is a primary reason for referral to pediatric pulmonary medicine. Although not perfect, the Asthma Predictive Index (API) is a valuable tool in directing care.⁴ Major risk factors for asthma in a preschool child with recurrent wheezing include 1) a parent with asthma and 2) a personal history of eczema. Minor risk factors include 1) allergic rhinitis, 2) wheezing not associated with respiratory infection, and 3) eosinophilia. Children with high-risk APIs likely have asthma and would benefit from therapy as suggested by the National Heart, Lung, and Blood Institute (NHLBI) Expert Panel Report 4.⁵ Those who do not most likely have infection-associated cough and wheeze and may also benefit from concomitant treatment with inhaled corticoid steroids and short-acting beta-agonists.⁵ 

Beyond PBB and asthma, the differential diagnosis for chronic cough among children becomes quite broad and complex. For this reason, multiple professional societies and organizations have developed algorithms for the assessment and treatment of children with chronic cough.^6-8 All of these guidelines suggest referral to pulmonary medicine after empiric treatment of PBB or asthma. 

Broadly speaking, the approach to chronic cough among children can be age-based or based on pathophysiology. Using an age-based approach, gastroesophageal reflux disease (GERD), infection, and congenital airway/lung differences are most frequently encountered among infants. Primary care professionals are quite familiar with the diagnosis and management of GERD, and referral to pulmonary medicine is not needed. Bordetella pertussis and Chlamydia trachomatis infections are of particular concern among newborns. Again, diagnosis and management of these common infections does not necessitate referral to pulmonary medicine. Congenital airway/lung differences typically identified on prenatal ultrasound examination include congenital pulmonary airway malformation, extralobar bronchopulmonary sequestration, and congenital diaphragmatic hernia. Any infant with a history of abnormal maternal ultrasound requires a chest radiograph immediately after birth and advanced imaging (CT scan) by 6 months of age. Other differences, including congenital lobar overinflation, bronchogenic cyst, intralobar bronchopulmonary sequestration, and esophageal atresia with tracheoesophageal fistula, are more commonly diagnosed after birth based on respiratory symptoms and imaging. 

For chronic cough among preschool and school-aged children, significant overlap exists, and a pathophysiology-based assessment by a pediatric pulmonologist is more appropriate. The exception to this guidance is when there is a high index of suspicion for an airway foreign body. Early preschool children (age 1-3 years) with sudden onset of unremitting cough and focal physical examination findings warrant referral to the emergency department and rigid bronchoscopy performed by otolaryngology (ENT).⁹  The other exception is habit/tic cough, which is referred to as one of the “classic diagnosable coughs.”¹⁰ This cough typically occurs in later school-aged children and is easily diagnosed as it does not occur during sleep. A variety of treatments have been recommended in the past, but many children benefit from speech pathology services. Other causes of chronic cough among children are rare but can be roughly divided into suppurative lung disease (cystic fibrosis, primary ciliary dyskinesia, immune deficiency and bronchiectasis), aspiration caused by dysphagia or upper airway differences, atypical infections, interstitial and diffuse lung diseases (ChILD), and a spectrum of others. All of these are appropriately referred for pulmonary medicine evaluation. 

References:

1. Wagner JB, Pine HS. Chronic cough in children. Pediatr Clin North Am. 2013;60(4):951-967. PMID: 23905830. doi:10.1016/j.pcl.2013.04.004
2. Kantar A, Chang AB, Shields MD, et al. ERS statement on protracted bacterial bronchitis in children. Eur Respir J. 2017;50(2):1602139. PMID: 28838975. doi:10.1183/13993003.02139-2016
3. Chang AB, Robertson CF, Van Asperen PP, et al. A multicenter study on chronic cough in children: burden and etiologies based on a standardized management pathway. Chest. 2012;142(4):943-950. PMID: 22459773. doi:10.1378/chest.11-2725
4. Castro-Rodríguez JA, Holberg CJ, Wright AL, Martinez FD. A clinical index to define risk of asthma in young children with recurrent wheezing. Am J Respir Crit Care Med. 2000;162(4 Pt 1):1403-1406. PMID: 11029352. doi:10.1164/ajrccm.162.4.9912111
5. Asthma management guidelines: focused updates 2020. National Heart, Lung, and Blood Institute. Last updated February 4, 2021. https://www.nhlbi.nih.gov/health-topics/asthma-management-guidelines-2020-updates
6. Morice AH, Millqvist E, Bieksiene K, et al. ERS guidelines on the diagnosis and treatment of chronic cough in adults and children. Eur Respir J. 2020;55(1):1901136. doi: 10.1183/13993003.01136-2019. Erratum in: Eur Respir J. 2020;56(5): PMID: 31515408; PMCID: PMC6942543.
7. Chang AB, Oppenheimer JJ, Irwin RS; CHEST Expert Cough Panel. Managing chronic cough as a symptom in children and management algorithms: CHEST Guideline and Expert Panel Report. Chest. 2020;158(1):303-329. PMID: 32179109. doi:10.1016/j.chest.2020.01.042
8. Chung KF, McGarvey L, Song WJ, et al. Cough hypersensitivity and chronic cough. Nat Rev Dis Primers. 2022;8(1):45. PMID: 35773287. PMCID: PMC9244241. doi:10.1038/s41572-022-00370-w
9. Parvar SY, Sarasyabi MS, Moslehi MA, et al. The characteristics of foreign bodies aspirated by children across different continents: a comparative review. Pediatr Pulmonol. 2023;58(2):408-424. PMID: 36373422. doi:10.1002/ppul.26242
10. Vertigan AE, Murad MH, Pringsheim T, et al; CHEST Expert Cough Panel. Somatic cough syndrome (previously referred to as psychogenic cough) and tic cough (previously referred to as habit cough) in adults and children: CHEST Guideline and Expert Panel Report. Chest. 2015;148(1):24-31. PMID: 25856777. PMCID: PMC4493876. doi: 10.1378/chest.15-0423