To get angry; to lose one's temper — a casual expression for feeling strong annoyance or irritation.
電車で足を踏まれて、頭にきた。
Someone stepped on my foot on the train and I got angry.
毎回遅刻する彼の態度には頭にくるよ。
His always-late attitude really makes me angry.
そんな言い方をするなんて、本当に頭にくる。
Saying something like that really makes me mad.
To hit one's head/glands — to go straight to one's head (of alcohol), or to feel the effects of an illness or substance (e.g., dizziness or intoxication).
このワインは強いね、すぐに頭にくるよ。
This wine is strong — it goes straight to my head quickly.
薬を飲んだら頭にきて少しふらついた。
After taking the medicine I felt it hit my head and got a bit dizzy.