Most children go through a stage where they like to see fire. This is normal. If they are taught about fire safety, supervised children can assist adults around a campfire.
Some children still manage to sometimes sneak away and play with fire.
This is frightening, but it is not a psychiatric disorder. A person with pyromania does not set fires for money, to express political beliefs, to hide signs of a crime, or to show anger. It is not pyromania if someone sets a fire in response to a delusion or hallucination. It is also not pyromania if the person setting the fire is in the manic phase of bipolar disorder, has a conduct disorder, or has an antisocial personality disorder. A true pyromaniac just likes fire.