Yes, there is an increased risk of a second concussion from a head injury sustained soon after a first concussion. This may be due to slower reaction times, dizziness, headache, and other concussion symptoms related to incomplete healing and recovery of the first concussion. That makes it especially important to follow expert recommendations about returning to work, school, and sports after a concussion. Complete healing helps reduce the risk that a minor head bump can cause a second concussion. See Second Impact Syndrome.