Police were called to a caravan site in Skegness this morning and the toddler was rushed to the Pilgrim Hospital in Boston. But he was later transferred to Leicester Royal Infirmary for specialist treatment.
The dog, possibly a Staffordshire bull terrier type, is thought to be owned by a relative of the lad who was visiting his grandparents at the caravan park.
A vet has since identified the dog as a terrier type and is being held in kennels until a dog expert can determine whether it may be of a breed outlawed under the Dangerous Dogs Act.
After the tragedy of the little girl savaged to death by a dog on Merseyside over Christmas, the latest dog attack on a child inevitably made the national teatime news - the photo here is the logo for the Liverpool Post's "Bite Back" campaign for a crackdown on dangerous dogs launched last summer.
BBC Radio Lincolnshire report a Lincolnshire Police spokesperson saying:
"We need to investigate the circumstances of the attack before taking a decision on whether to have the dog destroyed."She added (bizarely in my humble opinion) that there might have been an element of provocation which would be taken into account.
When will people realise that letting toddlers anywhere near dogs of a certain type - even if legal - is asking for trouble?