If my baby has a fever, do they have to be seen by a doctor?

Not necessarily: Not necessarily. A fever is usually a sign of infection and infections may be either mild or (less commonly), severe. More important than the presence of fever is how they look. Are they sluggish, won't feed, or cry without relief? Do they appear to have difficulty breathing or swallowing, a stiff neck, or purple or dark spots on the skin? If the answer is yes then they should be seen a doctor.

Depends: It depends on the age and symptoms. When in doubt, see your dr.