Does caffeine cause headaches?

Headaches have a wide variety of causes, ranging from eye strain, sinusitis and tension to life-threatening conditions such as encephalitis, meningitis, cerebral aneurysms and brain tumors (although up to 99% of headaches have a benign cause and do not warrant further treatment other than a painkiller). When the headache occurs in conjunction with a head injury the cause is usually quite evident; however, many causes are more unclear. The most common type of headache is a tension headache. Some experience headaches when dehydrated, or suffering from caffeine withdrawal symptoms.