Teachers and police officers in the UK should consider whether tantrums and excessive clinginess are possible signs of child abuse, a watchdog has said.
New guidance says professionals working outside the NHS should be alert to "soft signs" that a child is experiencing abuse or neglect.
These can include "frequent rages" with only a small amount of provocation, excessive clinginess, low self-esteem and recurrent nightmares.
Children may also be withdrawn, wet themselves regularly, persistently seek attention, or display over-friendliness to strangers.
The guidance, from the National Institute for Health and Care Excellence (Nice), says workers should consider abuse if a child displays behaviours that differ to what is normal for the child or for their age or developmental stage.
Dr Danya Glaser, a consultant child and adolescent psychiatrist and member of the Nice guideline development committee, said professionals should use their instinct and experience to make a judgement.
"It's probably a mixture of instinct and experience," she said. "It's about (noticing) some change in behaviour if you know the child.
"It's a change in behaviour or an intense behaviour that is worrying."
Dr Glaser said there was "far more under-recognition" of child abuse than over-reporting of cases that then turned out to be untrue.
"We are saying err on the side of curiosity - it might be nothing but it might be something," she said.
Dr Glaser said teachers should raise their concerns with the school's special educational needs co-ordinator (senco), who covers child protection.
But the guidance says some "red flags" are of such concern that social services should be alerted straight away.
These red flags include a child regularly attending school unclean or with injuries, overtly sexual behaviours in children who are below the age of puberty, and parents excessively smacking their children.
Gillian Leng, deputy chief executive of Nice, said: "We want all professionals to be aware and recognise when they need to ask questions or follow up with colleagues about a child's wellbeing.
"Not all cases will cause concern but if we do not ask, we may miss opportunities to protect children in their time of need.
"I guess we can be a bit British and perhaps aren't curious enough and think we shouldn't ask the questions, so I guess (the guideline is) permission to be curious."
Professor Corinne May-Chahal, a leading researcher in child protection at Lancaster University, said: "The guideline gives examples of soft signs, the behaviours or emotions a child is exhibiting, which could indicate something might be wrong.
"These may not always be proof of abuse or neglect taking place, but they underline when to check on a child's wellbeing."
Emma Harewood, the transformation lead for child sexual abuse services in London, said it can be frightening for some professionals to take the first step towards seeking help for children.
But she said that when they get "that niggly feeling" that something is not right, the guidance gives them the permission to take things further.
Figures from the NSPCC show there are currently more than 57,000 children identified as needing protection from abuse in the UK.
The charity estimates that for every child identified as needing protection from abuse, another eight are suffering abuse.
One in 20 children in the UK have been sexually abused while one in 14 have been physically abused.