CMA is the most common food allergy among infants and young children, and is estimated to affect 1.9% to 4.9% of children1, usually presenting in the first months of life.
The condition can affect both breastfed and formula-fed infants, although it is less common in breastfed infants.
CMA is the most clinically complex food allergy as it is capable of causing a multitude of differing presenting symptoms in infants. Also many of these symptoms can overlap with a number of other conditions that are commonly experienced in early childhood, e.g. reflux, colic, eczema. A further challenge is that CMA, more so than any other food allergy, can present with either delayed onset symptoms of non-IgE-mediated allergy or with acute onset symptoms of IgE-mediated allergy. The diagnosis and management of these two clinical expressions of CMA differs significantly.
Infants with CMA often experience unpleasant, painful symptoms, which can cause distress for infants and their families3. On rare occasions, they may be life threatening.
For a comprehensive list of symptoms please see the MAP Guideline.
Most infants grow out of CMA around the age of one to three years, while for others it takes a little longer4. Children with mild to moderate non-IgE-mediated CMA usually will grow out of it relatively quickly, even by their first birthday. IgE-mediated CMA or more severe forms of non-IgE-mediated CMA may well persist for longer.
Early recognition, timely diagnosis and appropriate management and dietary advice can all help to limit the impact of the condition on infants and their families5.
Immunoglobulin E (IgE)-mediated CMA is an immediate allergic reaction (type 1 hypersensitivity) which involves the IgE antibody.
Infants often react on their first known ingestion of milk. Symptoms tend to present within a few minutes after milk exposure. Reactions typically involve rapid onset skin signs, such as urticaria and angioedema, with severe reactions potentially leading rapidly to anaphylaxis.
Non-IgE-mediated CMA (type 4 hypersensitivity) produces delayed symptoms following ingestion, which makes diagnosis more difficult.
Symptoms usually occur within a couple of hours but can occur days after milk exposure and are commonly gastrointestinal (e.g. diarrhoea, reflux, colic) or cutaneous (e.g. chronic eczema) with the respiratory system sometimes involved.
1. Fiocchi A, Brozek J, Schünemann H et al. World Allergy Organization (WAO) Diagnosis and Rationale for Action against Cow's Milk Allergy (DRACMA) Guidelines. World Allergy Organ J 2010;3(4):57-161.
2. Venter C, Pereira B, Voigt K et al. Prevalence and cumulative incidence of food hypersensitivity in the first 3 years of life. Allergy 2008;63(3):354-9.
3. Venter C, Arshad SH. Epidemiology of food allergy. Pediatr Clin North Am 2011;58(2):327-49.
4. Santos A, Dias A, Pinheiro JA. Predictive factors for the persistence of cow’s milk allergy. Pediatr Allergy Immunol 2010;21:1127-34.
5. Mass D, Fox AT. The Challenge of Delayed Reactions [Online]. 2012. Available at: https://www.aptamilprofessional.co.uk/pdf/ACTCMAReport201208140314.pdf [Accessed Sept 2013].