As the World Cup kicks off, aspiring Wayne Rooneys and Ronaldinhos were today warned that wearing new football boots could kill them.

The warning follows the cases of two children who developed potentially fatal toxic shock syndrome, a rare and acute form of blood poisoning, after playing football in new boots.

The children, a 13-year-old girl and an 11-year-old boy, were hospitalised with toxic shock after developing blisters on their heels, according to a study. The blisters were found to contain the bacterium Staphylococcus aureus, which can cause wound and blood infections.

The girl was admitted to her local hospital after developing symptoms including fever, rash, abnormally low blood pressure, vomiting and diarrhoea. Her condition deteriorated as she suffered severe muscle weakness and kidney problems. Pus from the blisters in her heel was found to contain the gene for toxic shock syndrome.

She began to respond to antibiotics and was discharged after 12 days. A week later the skins of her hands and feet had peeled extensively. The girl has since made a full recovery.

In the second case, the boy suffered fever, vomiting and diarrhoea in the two days after he played football in his new boots. His condition deteriorated within hours of being admitted to hospital, as he suffered a rash and his temperature soared to 40C.

He too was found to have a blister on his heel containing Staphylococcus aureus. He was discharged after nine days after responding to antibiotic treatment and, as in the case of the girl, the skin of his hands and feet peeled.

The study, published in the British Medical Journal, concludes that toxic shock syndrome in children could be caused by far more minor skin abrasions than previously thought. It recommends that doctors noting symptoms of the syndrome, which is fatal in around 5% of child cases, should identify the source of infection and not discount the feet as has been previously suggested.