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 respiratory tract infections, asthma, bronchitis;gastro-oesophageal reflux disease, croup or whooping cough.

Chronic cough as a symptom of Cows' Milk Allergy
Up to 30% of infants with Cows' Milk Allergy (CMA) will present with a respiratory symptom such as chronic cough.4 CMA can be suspected in infants who display immediate symptoms of cough following the ingestion of cow’s milk protein.5,6

The majority of infants affected with CMA have at least two symptoms affecting at least two different organ systems.7,8 If you suspect non-IgE mediated CMA, you can use the CoMiSS® tool11 to score the combination of their symptoms and assess the likelihood of CMA.

Other signs and symptoms related to CMA6,9,10
  • Gastrointestinal/Digestive: Vomiting, reflux, regurgitation, anorexia, diarrhoea, constipation, abdominal pain, blood in stools
  • Respiratory: Chronic cough, sneezing, wheezing, shortness of breath, runny nose
  • Skin: Rash, atopic dermatitis, urticaria, angioedema
  • General: Failure to thrive, anaphylaxis, insomnia, inconsolable crying, pallor and tiredness

How to score this symptom with the CoMiSSTM 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 CMA are also present, they should also be given a score using the CoMiSSTM tool. These include diarrhoea, constipation, regurgitation and skin (atopic dermatitis and urticaria) symptoms


The Cows' Milk-related Symptom Score (CoMiSSTM) is a simple, fast and easy-to-use awareness tool designed to help you more easily recognise the signs and symptoms that can be cows' milk-related in infants and young children.


If you suspect your patient is suffering from symptoms that may be suggestive of CMA, use the CoMiSSTM tool to score and assess the likelihood of CMA.



  1. Chung KF. and Pavord IF. Lancet. 2008;371(9621):1364
  2. Pavord IF. and Chung KF. Lancet. 2008;371(9621):1375–84
  3. NHS Choices.Cough. (Accessed October 2016)
  4. Koletzko S., et al. J Pediatr Gastroenterol Nutr. 2012;55(2):221–9
  5. Vandenplas Y., et al. Arch Dis Child. 2007;92(10):902–8
  6. Caffarelli C., et al. It J Pediatr. 2010;36:5
  7. Koletzko S., et al. J Pediatr Gastroenterol Nutr. 2012;55(2):221–9
  8. Lifschitz C. and Szajewska H. Eur J Pediatr. 2015;174:141–50
  9. Høst A. Pediatr Allergy Immunol. 1994;5:1–36
  10. Luyt D., et al Clin Exp Allergy, 2014;44:642–672
  11. National Institute of Health Care and Excellence Clinical Knowledge Summarises. Cows’ milk protein allergy in children, 2015!diagnosissub/-617759 (Accessed October 2016)
  12. Vandenplas Y., et al. Acta Paed. 2015;104:334–9

IMPORTANT NOTICE: Mothers should be encouraged to continue breastfeeding even when their babies have cows' milk protein allergy. This usually requires qualified dietary counselling to completely exclude all sources of cows' 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.