CONFUSING an allergy with food intolerance is akin to confusing the effects of a mortar bomb and a Guy Fawkes rocket. Food intolerance is an abnormal reaction to some constituent part of the food; a common one is intolerance to lactose or milk. Rarely does it cause serious injury. Intolerance to food is not likely to give rise to anything more serious than inconvenience from nausea, wind, bloating, abdominal pain and diarrhoea.

A serious allergy to some food, or foods, however, in which the patient is hypersensitive to a particular protein, may be life-threatening. An allergen is the protein which overstimulates some people’s immune response so that it produces an antibody known as an IgE. This mechanism has nothing to do with those factors that stimulate intolerance.

Doctors are fascinated by the recent increase in the incidence of allergic problems. Hay fever, as well as other forms of allergic rhinitis, was not widespread enough to attract medical interest until the 19th century. The protection of children from toxins in the aseptic, animal-free 21st century of scrubbed and disinfected modern houses may result in a toddler’s immune system becoming oversensitive. Later, when confronted by potential allergens, they develop an allergic response to them. It used to be rare for country children, who have had a truly rural rather than suburban upbringing, to have allergies. They were exposed to a wide variety of pollens while still in their prams, and the squalor and filth of the kitchen floor may make a modern health visitor or social worker blanch, but it tuned the infant’s immune system so it could deal effectively with future problems.

This generation has been brought up in a sanitised era and must take appropriate steps to avoid disasters. Parents should start by reducing the risk of peanut and other nut allergies, which can kill as fast as any poison.

Precautions begin during pregnancy and breast-feeding if there is a family history of allergic disease. The advice is that if the mother, father, brother or sister of the expected or breast-fed child has had any allergies, the pregnant or nursing mother should avoid all contact with peanuts or peanut products. Once breast-feeding is over, the child should avoid all foods containing nuts until they are three, possibly even older. (In any case no child under five should eat solid peanuts for fear of choking.)

If a child has shown any form of allergy to peanuts or other nuts, the parents must be aware of the emergency treatment for anaphylactic shock, and of the need to carry an EpiPen for immediate use.

DR THOMAS STUTTAFORD