Cough is a reflex action of the respiratory tract that is used to clear the upper airways.1 In contrast, chronic cough is a cough that remains unexplained after basic clinical assessment.2

Chronic cough is a cough which lasts for more than three weeks and is a common reason for referral to secondary care.2

What causes chronic cough in infants?

Chronic cough in infants can be related to several environmental or pathogenic triggers.1 Environmental factors include exposure to cigarette smoke, and exposure to environmental pollution.1 Diseases that cause chronic cough include asthma, bronchitis, gastro-oesophageal reflux disease, postnasal drip syndrome or rhinosinusitis.1

baby cough

Chronic cough as a symptom of Cow’s Milk Protein Allergy

Up to 30% of infants with Cow’s Milk Protein Allergy (CMPA) will present with a respiratory symptom such as chronic cough.3 CMPA can be suspected in infants who display immediate symptoms of cough following the ingestion of cow’s milk protein.4,5

The majority of infants affected with CMPA have at least two symptoms affecting at least two different organ systems6,7 If, in addition to a respiratory symptoms such as chronic cough, your patient shows any of the signs and symptoms that can be related to CMPA5 (see below), you can use the CoMiSS® tool8 to score the combination of their symptoms and assess the likelihood of CMPA.

Signs and symptoms related to CMPA5

· Gastrointestinal/Digestive: Colic, vomiting, reflux, regurgitation, anorexia, diarrhea, constipation

· Respiratory: Sneezing, wheezing, runny nose

· Skin: Atopic dermatitis, urticaria, angioedema

· General: Failure to thrive, anaphylaxis, insomnia, inconsolable crying

How to score this symptom with the CoMiSS® tool

·         The combination of respiratory symptoms is given a score

·         The higher the score the greater the severity of symptom

·         In addition to the respiratory symptoms, if any of the following signs or symptoms related to CMPA are also present, they should also be given a score using the CoMiSS® tool. These include diarrhea, constipation, regurgitation and skin (atopic dermatitis and urticaria) symptoms

CoMiSS® awareness tool

The Cow’s Milk-related Symptom Score (CoMiSS)® is a simple, fast and easy-to-use awareness tool designed to help you more easily recognise the signs and symptoms that can be cow’s milk-related in infants and young children.

CoMiSS® awareness tool is available in print and online version
If you suspect your patient is suffering from symptoms that may be suggestive of CMPA, use the CoMiSS® tool to score and assess the likelihood of CMPA.



1.    Chung KF. and Pavord IF. Lancet. 2008;371(9621):1364–74

2.    Pavord IF. and Chung KF. Lancet. 2008;371(9621):1375–84

3.    Vandenplas Y., et al. Arch Dis Child. 2007;92(10):902–8

4.    Caffarelli C., et al. It J Pediatr. 2010;36:5

5.    Koletzko S., et al. J Pediatr Gastroenterol Nutr. 2012;55(2):221–9

6.    Lifschitz C. and Szajewska H. Eur J Pediatr. 2015;174:141–50

7.    Høst A. Pediatr Allergy Immunol. 1994;5:1–36

8.    Vandenplas Y., et al. Acta Paed. 2015;104:334–9

IMPORTANT NOTICE: Mothers should be encouraged to continue breastfeeding even when their babies have cow’s milk protein allergy. This usually requires qualified dietary counseling to completely exclude all sources of cow’s milk protein from the mothers’ diet. If a decision to use a special formula intended for infants is taken, it is important to follow the instructions on the label. Unboiled water, unboiled bottles or incorrect dilution can make babies ill. Incorrect storage, handling, preparation and feeding can eventually lead to adverse effects on the health of babies. Formula for special medical purposes intended for infants must be used under medical supervision.