Lead may even have some long-term effects upon IQ and actual nervous system functions. Signals that a child might have lead poisoning range from not feeling very well and being colicky, to seizures and anemia. The homes that have lead problems are usually older homes that were painted when lead components in paint were very common. When it was realized that lead was a health hazard, the paint companies stopped using lead as a major component. The general guideline is if a house is over 25 or 30 years old, the paint in the home probably has lead in it.
Lead poisoning can also affect pets.
When animals walk on the ground they can get lead dust on their paws. Then they'll groom themselves, and will ingest the lead at a much higher concentration. Even though you paint over a wall that was once coated with lead paint, the paint can chip off exposing underlying paint with lead in it. Testing is the only way to be sure that you don't have lead in your home. Take scrapings to a lab for testing.