Children should be allowed to get dirty, according to scientists who have found being too clean can impair the skin's ability to heal.
Normal bacteria living on the skin trigger a pathway that helps prevent inflammation when we get hurt, the US team discovered. The bugs dampen down overactive immune responses that can cause cuts and grazes to swell, they say. Their work is published in the online edition of Nature Medicine.
Experts said the findings provided an explanation for the "hygiene hypothesis", which holds that exposure to germs during early childhood primes the body against allergies. Many believe our obsession with cleanliness is to blame for the recent boom in allergies in developed countries.
Researchers from the School of Medicine at University of California, San Diego, found a common bacterial species, known as Staphylococci, blocked a vital step in a cascade of events that led to inflammation.