Background Information on Prolonged Cough in Young Children
Prevalence of Prolonged Cough
Coughing in young children during colds is common – three out of four children under the age of 4 cough during a cold (1), and daycare significantly increases the number of cold days for children (2). However, normal cough associated with a cold lasts no more than 2-3 weeks, and the child recovers symptom-free between colds (3,4). When a child’s daily cough persists for at least four weeks, it is considered prolonged cough, which can be continuous or recur in prolonged periods of over four weeks (5).
The prevalence of prolonged cough in children has varied in previous studies depending on the question and age range (1,6): 17-38% of children under 4 years old cough outside of colds, but only 9-11% cough more than their peers according to their parents’ assessment (1,7). Dry night cough occurs in 9-12% of school-aged children (8,9), but in 14-40% of children under 4 years old (1,10,11). Therefore, the prevalence of prolonged cough in young children is estimated to be around 15-30% in the general population, but due to varying survey designs, unequivocal research data is not available. In Finland, the issue has not been studied according to current definitions.
In any case, cough is a common reason to take a child to the doctor’s office – in a large English birth cohort study (ALSPAC), 30-40% of all children under 5 had visited a doctor for cough in the previous year (12). In addition to repeated doctor visits, prolonged cough in a child is associated with significant family burden and decreased quality of life (13,14).
Causes of Cough – A Child is Not a Small Adult
In adults, the most common causes of prolonged cough include asthma, gastroesophageal reflux, and upper respiratory (nose/throat/sinus) causes (5,15). Treatment guidelines for prolonged cough in adults widely recommend medication trials before more detailed diagnostic investigations (5,15).
The current understanding of the causes of prolonged cough in children has been refined over the past two decades, and in practice, the approach has partly reversed in North American, British, and European treatment recommendations: the treatment of prolonged cough in children should be based on the identified cause through investigations (4,5,16).
In follow-up studies using treatment pathways designed for children (17-20), the most common cause of prolonged cough in children has been prolonged bacterial bronchitis (11-41%), and other common causes reported include asthma (5-27%) and spontaneously resolving cough (approx. 14-22%). In contrast, prolonged cough due to gastroesophageal reflux or upper respiratory causes, such as sinusitis, is rarer in young children but not uncommon, and the neural sensitization of the cough reflex (chronic cough) seen in adults is not known to occur in young children at all (21).
Other rare causes of prolonged cough in children may include unnoticed foreign objects in the airways, rare hereditary lung diseases or immune deficiencies, childhood tic disorder (Tic disorder), or congenital structural abnormalities of the airways.
Especially in daycare and preschool-aged children, the immaturity of respiratory structures and immune response predisposes to the prolongation of common respiratory infections (21). In a systematic review, an American expert panel assessed that the causes of prolonged cough in children differ from those in adults at least until the age of 12 (22) and that children’s cough should be investigated and treated according to guidelines designed for children (23).
FINNCHICO-study aims to clarify the aforementioned gaps in current knowledge in protracted cough prevalence, aetiology and effective treatment modalities. The study is scheduled to start recruiting next fall in Tampere.
The study procedures will be undertaken in Finnish, thus the participants (families) need to be sufficiently fluent in oral and written Finnish-language.
References
1) Jurca M, Ramette A, Dogaru CM, Goutaki M, Spycher BD, Latzin P, et al. Prevalence of cough throughout childhood: A cohort study. PLoS One 2017 May 24;12(5):e0177485.
(2) Schuez-Havupalo L, Toivonen L, Karppinen S, Kaljonen A, Peltola V. Daycare attendance and respiratory tract infections: a prospective birth cohort study. BMJ Open 2017 September 05;7(9):e014635-014635.
(3) Hay AD, Wilson AD. The natural history of acute cough in children aged 0 to 4 years in primary care: a systematic review. Br J Gen Pract 2002 May 01;52(478):401-409.
(4) Shields MD, Bush A, Everard ML, McKenzie S, Primhak R, British Thoracic Society Cough Guideline Group. BTS guidelines: Recommendations for the assessment and management of cough in children. Thorax 2008 April 01;63 Suppl 3:iii1-iii15.
(5) Morice AH, Millqvist E, Bieksiene K, Birring SS, Dicpinigaitis P, Domingo Ribas C, et al. ERS guidelines on the diagnosis and treatment of chronic cough in adults and children. Eur Respir J 2020 January 02;55(1):10.1183/13993003.01136-2019. Print 2020 Jan.
(6) Faniran AO, Peat JK, Woolcock AJ. Measuring persistent cough in children in epidemiological studies: development of a questionnaire and assessment of prevalence in two countries. Chest 1999 February 01;115(2):434-439.
(7) Luyt DK, Burton PR, Simpson H. Epidemiological study of wheeze, doctor diagnosed asthma, and cough in preschool children in Leicestershire. BMJ 1993 May 22;306(6889):1386-1390.
(8) Timonen KL, Pekkanen J, Korppi M, Vahteristo M, Salonen RO. Prevalence and characteristics of children with chronic respiratory symptoms in eastern Finland. Eur Respir J 1995 July 01;8(7):1155-1160.
(9) Leonardi GS, Houthuijs D, Nikiforov B, Volf J, Rudnai P, Zejda J, et al. Respiratory symptoms, bronchitis and asthma in children of Central and Eastern Europe. Eur Respir J 2002 October 01;20(4):890-898.
(10) Ranciere F, Nikasinovic L, Momas I. Dry night cough as a marker of allergy in preschool children: the PARIS birth cohort. Pediatr Allergy Immunol 2013 March 01;24(2):131-137.
(11) Linehan MF, Hazell ML, Frank TL, Frank PI. Prevalence of respiratory symptoms in under 5s: 1993 to 2001. Arch Dis Child 2005 May 01;90(5):516-519.
(12) Hay AD, Heron J, Ness A, ALSPAC study team. The prevalence of symptoms and consultations in pre-school children in the Avon Longitudinal Study of Parents and Children (ALSPAC): a prospective cohort study. Fam Pract 2005 August 01;22(4):367-374.
(13) Marchant JM, Newcombe PA, Juniper EF, Sheffield JK, Stathis SL, Chang AB. What is the burden of chronic cough for families? Chest 2008 August 01;134(2):303-309.
(14) Prime SJ, Carter HE, McPhail SM, Petsky HL, Chang AB, Graves N, et al. Chronic wet cough in Australian children: Societal costs and quality of life. Pediatr Pulmonol 2021 May 03.
(15) Irwin RS, Baumann MH, Bolser DC, Boulet LP, Braman SS, Brightling CE, et al. Diagnosis and management of cough executive summary: ACCP evidence-based clinical practice guidelines. Chest 2006 January 01;129(1 Suppl):1S-23S.
(16) Chang AB, Glomb WB. Guidelines for evaluating chronic cough in pediatrics: ACCP evidence-based clinical practice guidelines. Chest 2006 January 01;129(1 Suppl):260S-283S.
(17) Gedik AH, Cakir E, Torun E, Demir AD, Kucukkoc M, Erenberk U, et al. Evaluation of 563 children with chronic cough accompanied by a new clinical algorithm. Ital J Pediatr 2015 October 06;41:73-0.
(18) Karabel M, Kelekci S, Karabel D, Gurkan MF. The evaluation of children with prolonged cough accompanied by American College of Chest Physicians guidelines. Clin Respir J 2014 April 01;8(2):152-159.
(19) Chang AB, Robertson CF, Van Asperen PP, Glasgow NJ, Mellis CM, Masters IB, et al. A multicenter study on chronic cough in children : burden and etiologies based on a standardized management pathway. Chest 2012 October 01;142(4):943-950.
(20) Marchant JM, Masters IB, Taylor SM, Cox NC, Seymour GJ, Chang AB. Evaluation and outcome of young children with chronic cough. Chest 2006 May 01;129(5):1132-1141.
(21) Chang AB. Pediatric cough: children are not miniature adults. Lung 2010 January 01;188 Suppl 1:33.
(22) Chang AB, Oppenheimer JJ, Weinberger M, Grant CC, Rubin BK, Irwin RS, et al. Etiologies of Chronic Cough in Pediatric Cohorts: CHEST Guideline and Expert Panel Report. Chest 2017 September 01;152(3):607-617.
(23) 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 July 01;158(1):303-329.