My wife is experiencing headache after hitting the top of her head against the edge of the kitchen door cabinet?

Head ache: This can certainly be common with even mild head injuries, but caution needs to be taken. Depending on the extent of the force of her injury, she could have a subdural hematoma (SDH) which is serious and would need emergent treatment to prevent serious consequences, so,...the long and short of it is, without an exam, over the computer, a headache post a traumatic head injury needs to be seen.

Headache : Would be normal. If it worsens and she vomit. Vision blurs, speech slurs, gait is not normal, memory becomes impaired head for the ER