Exposure to germs can actually protect children from some allergies

By Thomas Kaerst Oct 23, 2006, 5:03 GMT

Berlin - Many parents go to extremes to protect their infant children from germs. Their kitchen floor is always spick and span, the baby formula is sterilized and they use antibacterial solutions to clean the baby's bedroom.

But this dedication to cleanliness can actually cause more problems for children than it solves. A recently published survey conducted in Germany confirms a hygiene hypothesis stating that an overemphasis on cleanliness is responsible for allergies.

Children from families with a lower socio-economic status who have older siblings or who go to nursery school at a younger age are often less affected by allergies, according to the Children and Youth Health Survey conducted by the Robert Koch Institute in Berlin. The survey examined 18,000 children throughout Germany over an extended period of time.

The findings showed that only 13.6 per cent of children from households with a lower socio-economic status suffered allergies such as hay fever or neurodermatitis compared to 19 per cent of children from families at a higher socio-economic level.

The data confirms previous studies and hypotheses about allergies, said professor Torsten Schaefer, an allergist at the University of Luebeck and cited the example of children raised on farms who have contact with animals from a young age as they suffer allergies less frequently.

'Early exposure is needed to stimulate the immune system,' Schaefer said.

Ulrich Fegeler, a paediatrician in Berlin, said the immune system appears to need 'something to bite into.' If this isn't present, the immune system directs itself against the body and an allergy develops.

Children are exposed to germs through contact with other children their age in kindergartens and at school.

'Older siblings also spread bacteria,' said Fegeler, who is a state chairman of Germany's professional association of paediatricians, based in Berlin.

Children facing educational challenges, and who tend to be otherwise marginalized and sicker than children from families in the middle of the socio-economic spectrum, benefit when it comes to allergies from their 'robust exposure to the environment.'

Parents need not wipe their children down with a disinfectant, said Fegeler. A normal wash routine at home is sufficient. Parents should not categorically forbid their children putting things in their mouths.

'Children use their mouths to test out materials,' he said. When children get sand in their mouths while they are at the beach, it's not a reason to get upset, he added.

However, the connection between a germ-free environment and allergic tendencies does not hold true for all allergies, particularly those that are hereditary, said Schaefer. Exactly where the border lies between germs that are desired and unwanted germs is difficult to define.

Children should in any case be inoculated against mumps, measles and tetanus because these diseases can be dangerous, Schaefer said. Also, there are studies indicating that inoculated children develop allergies less frequently those who are not inoculated.

In recent years, experts have altered their thinking on the connection between pets and allergies. While in the past children who were believed to have a genetic predisposition to allergies were advised not to have pets, experts now say it depends on the type of pet.

'A cat, guinea pig or rabbit remain the least favourable pets, but there are no objections to a dog,' said Schaefer.

The best means of preventing an allergy is mother's milk, Fegeler said.

'When children are nursed, a very specific bacteria develops in the intestines,' said Fegeler. The digestive system can dispense with viruses and pathogens more quickly when these bacteria are present. Mother's milk also strengthens the immune system.