A 7 month old boy called Grant presented to his general practitioner (GP) with discomfort when feeding and diarrhoea. He had been initially breast fed, but this was discontinued after several weeks and formula milk was introduced, with no change to his symptoms. His GP made a presumptive diagnosis of cow’s milk intolerance and advised a change to a soya based milk; he also referred him to a general paediatrician at his local district general hospital.

The paediatrician agreed that cow’s milk intolerance was the most likely diagnosis and prescribed a whey hydrolysate, which Grant refused to drink, and then Neocate (amino acid based milk substitute), which he tolerated. Nevertheless, the diarrhoea (two semi-formed stools per day), vomiting, and “pains” on feeding continued, although he appeared well nourished with his weight on the 91st centile and height on the 75th centile. Since the symptoms had persisted, the following investigations were ordered: blood count (normal), renal function (normal), serum IgA (normal) and endomesial antibodies (negative), and radioallergosorbent tests (RAST, negative). An oesophageal pH study was also organised.

The paediatrician knew that allergies to cow’s milk in the absence of immediate symptoms (urticaria, bronchospasm, profuse diarrhoea) are likely to be non-IgE mediated and therefore RAST test negative. The paediatrician was also aware that symptoms of chronic diarrhoea and discomfort may be a type IV hypersensitivity reaction to cow’s milk protein, which is reported to be associated with gastro-oesophageal reflux. In view of the persistence of symptoms there were some concerns regarding compliance, but it was decided to await events.

Grant was admitted to hospital at 8 months of age with acute gastroenteritis caused by rotavirus, from which he made a full recovery and was noted to be passing normal stools before discharge.

At 11 months of age, he was seen in clinic …