When does a normal fear become a phobia that needs professional help?

Normal fears are temporary, age-appropriate (storms, dogs, needles), and don't significantly disrupt daily life. A phobia is an intense, persistent fear that lasts longer than 6 months, is disproportionate to the actual danger, and interferes with normal activities — refusing to go to school, avoiding all social situations, or having panic attacks. The gold-standard treatment is cognitive-behavioral therapy (CBT), especially exposure-based therapy, which is highly effective in children. Don't wait for them to 'grow out of it' if fear is limiting their life. Consult your pediatrician for a referral.