Doctors are being issued with new guidance for cases where children are repeatedly brought in when there is nothing wrong.
The Royal College of Paediatrics and Child Health (RCPCH) says cases where parents know there's nothing wrong are rare.
Instead genuine, if misplaced, health anxieties are more common.
They advise referring to "perplexing symptoms" instead of "fabricated or induced illness".
Paediatricians say there has been a rise in cases where children are repeatedly brought in, despite nothing being found to be wrong.
The unexplained symptoms could be because a genuine condition has not yet been diagnosed.
And there are cases where a parent or carer might make up or cause illness in their children - a rare form of abuse which used to be known as Munchausen's By Proxy Syndrome.
But often, doctors say, it is genuine concerns - and they believe the rise may be fuelled by bad information online.
'Incorrect beliefs or misplaced anxiety'
The RCPCH has updated its decade-old guidance to suggest "fabricate or induced illness" should only be used if there is evidence a child is about to come to serious harm.
For cases where there is no immediate risk to their safety, the guidance recommended a move to talking about children with "perplexing presentation".
This puts emphasis on the fact the doctor doesn't yet know what the problem is rather than on "blaming" parents, said Dr Danya Glaser, a psychiatrist who specialises in child protection.
"If a parent is anxious about their child, you have to listen, you have to actually look at the child and find out if their anxiety is not misplaced," she said.
If, after nothing has been found, a parent continues to keep their child away from school and seeks a third or fourth medical opinion to the point that it begins to harm the child, that's when further conversations need to be had, Dr Glaser added.
Keeping an open mind allows for the fact a small number of these children could have "that one rare condition", said Dr Emilia Wawrzkowicz, a consultant paediatrician and safeguarding specialist for Cambridge and Peterborough.
Previously, if fabrication or exaggeration was suspected, doctors would share information with children's social care without telling parents what they were doing.
The new guidance says parents should be told if information was going to be shared, as part of what Dr Glaser described as an "open and honest dialogue".
Much of the medical literature around Munchausen's By Proxy has focused on parents trying to deceive doctors by falsifying medical records, symptoms or causing their children to become ill.
But Dr Alison Steele, the RCPCH's safeguarding officer said it was "very rare for parents or carers to deliberately induce illness in a child by, for example, poisoning them or withholding treatment.
"Most cases are based on incorrect beliefs or misplaced anxiety which, unchecked, can cause children to undergo harms ranging from missing school and seeing friends, to undergoing unnecessary and painful or even harmful tests and treatments".
The key aim should be getting the child back in to education and away from unnecessary medical interventions, the guidance says, as well as providing appropriate support and mental health care for the parent or carer.