A growing number of families are using unproven DIY allergy kits to test whether their children's behaviour is being affected by common foods or substances.
Doctors are worried that many parents are bypassing their GP by using the internet or health food shops to buy the kits.
The Royal College of Physicians reported last year that the incidence of allergy has increased dramatically in the UK, and is still rising, with as many as one in three people developing an allergy at some point in the lives.
Levels of asthma, rhinitis (hayfever), and eczema have increased three-fold in the past 20 years but food allergies are the most widespread form, with a reaction to peanuts the most dangerous of all, affecting one in 70 children in Britain.
The DIY tests usually involve the patient having a pin prick for a sample of blood which then sees if there are higher than normal levels of allergen antibodies (known as IgE) in the blood. But often this can lead to mothers cutting out wheat or dairy from a child's diet even though the results may be incorrect.
Dr Gideon Lack, paediatric allergy specialist at St Mary's Hospital in west London, said: 'I have grave concerns about these testing kits, especially where people go into health food shops or department stores and have these unproven tests."
'If parents are worried that their child has an allergy, they should go to their doctor. They shouldn't resort to these unproven methods. Misinterpretation of these tests results is at best harmless, but at worst can have serious nutritional consequences. That's something we see in our clinics, where patients have received multiple false diagnoses, and the children ends up not gaining weight, or becoming seriously anaemic.'
Allergy testing is big business in the UK, with thousands of people every year buying a kit off the internet, or through supermarkets or local shops.
The NHS is not equipped to deal with the vast demand for these tests. In 2003, there were only six major centres which could offer a full-time service with expertise in all types of problems. The others are run part-time by consultants who also work in other disciplines. There is roughly one allergy consultant for every two million people in the UK.
Home testing kits can cost as little as £10. It is estimated that as many as one in 20 children in the UK have attention deficit hyperactivity disorder (ADHD) which can cause problems such as aggression and disruptive behaviour, disrupting schooling.
There is controversy over how much the disorder, which is increasingly diagnosed, is linked to diet. Some studies have suggested certain processed foods which contain artificial colours, flavours and preservatives can affect their behaviour. But others say there is a distinct lack of rigorous studies to prove such a link.
Sally Bunday, founder of the Hyperactive Children's Support Group, said that giving children a healthy breakfast is important as is drinking lots of water during the day. 'As well as their regular supplements of vitamins, minerals and essential fatty acids, the key with this group of children is consistency, giving them regular mealtimes and routine,' she said.
But a new trend that is starting to appear in the UK is that of the ADHD coach, charging about £160 for four private sessions, who will help families, both parents and children, deal better with the condition, says Allergy magazine, a new publication out this week.
After making an assessment of the patient, coaches can help to control the levels of hyperactivity by persuading them to change the way they see their life and to control the condition, sometimes by watching what they eat.
Jan Assheton, a nurse whose own 14-year-old has ADHD, helps scores of children and parents to learn how to manage it. 'It's really about offering families solutions. I look at the core deficits of hyperactivity, which are impulsivity, inattention and hyperactivity. Something which often helps is the "stop, think, act" technique, which teaches children to stop before they do something which may get them into a difficult or aggressive situation.'
Assheton, from Formby, Merseyside, believes that diet can be important for children but is also a proponent of medication, such as Concerta, a type of ritalin. 'No parent ever medicates their child out of choice, they are brain-altering chemicals after all. But when I saw my son sitting still and reading instead of bouncing off the bed I had to accept it.'
One father who did decide to alter his son's diet radically after he realised the boy was hyperactive says he has not regretted it. Ryan Gallacher's father Alex became increasingly concerned about the boy's behaviour and in desperation, the family decided to put him on a diet that was completely free of additives and sweets. According to the family, his behaviour was transformed and teachers are really impressed by the changes.
