The NHS is failing to keep up with the growing number of allergy sufferers, with new figures today showing that only a handful of specialist doctors across the country are running clinics for them.

One in three people in Britain can expect to suffer from some form of allergy during their lifetime - including 2 million people in the UK thought to have some allergy to food - but there has been barely any increase in NHS services to cope with this. Experts will warn this week that demand for care is outstripping the NHS's ability to cope, and many patients go to private clinics or dietitians that may offer unconventional diets.

The Royal College of Physicians has found that in 2003 there were just four junior doctors enrolled in the five-year specialist training programme for allergies. This year there are seven. The number of fully trained allergy consultants has risen from 19 to 29 though there are more than 12 million people seeking help. It is thought that there are only six full-time allergy clinics in Britain.

Some patients wait more than a year to see a consultant to get a proper diagnosis. GPs receive little training in allergies, but are usually the first port of call.

Dr Jonathan Brostoff, who will speak on the issue at the Allergy Show in London this week, said: 'If you have a food allergy it can have a debilitating effect on your life. Sometimes people end up in private clinics where they go on really gruelling dietary regimes, such as being told to eat lamb, carrots and pears for three months. It certainly doesn't make them better and they may end up worse as a result. Often they pay quite a bit and end up being left to get on with it.' He said there was still enormous scepticism within the health service about whether patients 'truly' had an allergy or were just imagining it.

Britain has one of the highest rates of allergy in the world, along with America, Australia and New Zealand. For reasons not understood, in the last 20 years the rate of eczema and asthma has at least doubled, and there has been at least a threefold increase in nut allergies. Before the mid-Nineties nut allergies were rare, but one in 50 schoolchildren now has one. In the last four years the number of adults with food allergies has also shot up, partly as a result of more awareness, with thousands suffering reactions to shellfish, vegetables, seeds, nuts, kiwis and plums.

Dr Gideon Lack, who runs allergy services at the Guy's and St Thomas's Trust in London, said: 'Demand is continuing to grow, but it's not matched by the levels of services.' There is also evidence that severe reactions are becoming more widespread. Prescriptions for EpiPens - devices that shoot adrenaline into a patient going into anaphylactic shock - have risen from 45,000 in 1998 to 153,000 in 2005.