Nearly 80% of 500 doctors polled, thought their colleagues confused milk allergy symptoms with other conditions. Experts say the problem lies in the symptoms being both vague and common - including skin rashes and diarrhoea. The poll also found many of the doctors did not know the best treatment.

Many of the doctors questioned, however, said they would advise a soy-based formula. The Department of Health and the British Dietetics Association advise against this because soy contains high levels of compounds called phytoestrogens that mimic the action of the female hormone oestrogen and which could pose a risk to the long-term fertility of infants.

There is also a risk that babies who are allergic to cow's milk will also be allergic to soy milk, and sheep and goat's milk. The researchers say cow milk protein allergy is a very common problem - at least 10,000 UK babies are thought to be affected. However, this is disputed by some doctors, who argue the condition is much rarer.

Nearly all of the doctors questioned agreed that better information would make it much easier to diagnose the condition in infants. The taskforce, which includes expert paediatric gastroenterologists, has developed guidance for doctors that will be published next year.

Left untreated, infants with food allergies can fail to thrive and grow, have developmental problems and can develop severe shock and even die. The World Health Organization recommends that babies are breastfed for the first two years of their lives if possible.