Frequent headaches: causes, what to measure at home and when to worry

Headache two or three times a week. You had a blood test and it came back normal, they took your blood pressure at the pharmacy and it was fine, and the conclusion was “stress”. It may be true, but “stress” is not a plan. This text explains why blood rarely answers this question, what you can measure, and how to arrive at the appointment with something better than “it hurts often”.

First, the important part: some headaches do not allow calm reading. If yours was sudden and the worst of your life, comes with fever and a stiff neck, with weakness, trouble speaking or confusion, or started after a blow to the head, close this page and seek medical care now.

Almost all frequent headaches are “primary”

The international classification of headache disorders distinguishes primary headaches, which are the problem in themselves (tension-type headache, migraine, cluster headache), from secondary ones, which are the symptom of something else.^[1] Primary headaches are by far the most common: episodic tension-type headache is reported by more than 70 % of some populations, and headache disorders as a whole affect about 40 % of people worldwide.^[2]

This explains the usual frustration: you get tests, they come back normal, and nobody tells you what you have. In a primary headache there is nothing to look for in the blood, because the cause is not there. What there is, is a pattern, and the pattern is discovered by recording, not by testing.

The two numbers that change the appointment

If you are only going to write down two things for a month, make them these: how many days your head hurt and how many days you took a painkiller. The international classification defines medication-overuse headache as pain on 15 or more days a month, in someone with a pre-existing headache, who for more than three months regularly takes painkillers: 15 or more days a month for simple analgesics, 10 or more for triptans, ergots, opioids or combinations.^[3] In other words: the remedy can be what keeps the pain going, and it is one of the most common and most treatable causes of chronic headache. It affects up to 5 % of some populations, women more than men.^[2]

The triggers you can measure at home

Several headache triggers have published criteria with concrete numbers. No need to guess: you record them for a few weeks and check whether they coincide with the episodes.

Sleep and stress

Pressing pain on both sides, “like a band”, worse at the end of the day or in weeks of little rest, is the classic description of tension-type headache.^[1] The useful log is real sleep hours and resting heart rate every morning: a week of short sleep and a resting heart rate above your usual often precedes the run of pain. If you wear a watch, you already have that data.

Caffeine

Caffeine relieves some headaches and causes others. The criterion for caffeine-withdrawal headache is clear: consumption of more than 200 mg a day for more than two weeks (about two cups of filter coffee), and a pain that appears within 24 hours of the last dose, is relieved by 100 mg of caffeine or goes away on its own within a week.^[4] The weekend headache, when you have a late breakfast without coffee, is the typical example. What you note: how much caffeine, at what time, and whether the pain comes on the days you change the routine.

Hours without food and water

The classification recognises headache attributed to fasting: it appears after 8 or more hours without eating and clearly improves on eating.^[5] It is independent of blood glucose level in most people, so a normal glucose does not rule it out. You record the time of each meal and the start time of the pain; dehydration is noted alongside, because it usually goes with the same disordered day.

Menstrual cycle

Pure menstrual migraine has an exact definition: attacks exclusively between day 2 before and day 3 after the start of menstruation (day 1 ± 2), in at least two out of three cycles and at no other time.^[6] Confirming it needs no hormone test: it needs a three-cycle calendar with the pain days marked. If you use My Cycle in Previva, the log already exists.

Blood pressure

Here precision matters, because there is a widespread myth. Ordinary high blood pressure, the kind treated with pills, usually does not hurt. Headache attributed to hypertension in the international classification requires very marked rises: systolic 180 or more, diastolic 120 or more, with a pain that remits when pressure comes down.^[7] That said, measuring your pressure is still worth it: a pressure repeatedly at or above 140/90 in the office defines hypertension under European guidelines,^[9] and discovering it through a headache that in the end was not its doing is still a good deal.

For home readings to count, technique matters as much as the device: an upper-arm cuff (not wrist), five minutes of rest, no coffee, tobacco or exercise in the previous half hour, arm supported at heart level, two readings one minute apart, at the same time each day.^[10] Seven days in a row, morning and evening, give your doctor something to work with.

What a blood test can show (and what it cannot)

With a frequent headache and no warning signs, blood tests almost always come back normal, and that is not a failure of the test: it confirms that the headache is primary. The exceptions a doctor may want to rule out are few: an anaemia that explains tiredness and pain together (blood count and ferritin), a glucose that swings too much (fasting glucose, HbA1c), and in some cases the thyroid (TSH). None is ordered “for the headache” as such; they are ordered for the rest of the picture.

Warning signs: when you do not log, you consult

Neurologists use a list of red and orange flags to detect the few headaches that are the symptom of something else.^[8] In plain language, a headache calls for immediate care when it:

• Comes all at once, peaking within seconds or a minute, “the worst of my life”.
• Comes with fever, stiff neck, a skin rash or intense general malaise.
• Brings weakness on one side, trouble speaking, double vision, confusion or fainting.
• Starts for the first time after age 50, or clearly changes pattern compared with your usual pain.
• Worsens on coughing, bending or exertion, or differs depending on whether you lie down or stand.
• Appears after a blow to the head, during pregnancy or postpartum, or if you have low immunity or a history of cancer.
• Comes with eye pain and blurred vision, or with tenderness when touching the temple.

How to log headaches so the appointment is useful

A four-week diary is the tool specialists use most, and the one almost nobody brings. It does not have to be elaborate; it has to be consistent.

1. Date, start time and end time of each episode.
2. Intensity 0 to 10 and side: one side, both, back of the head, forehead.
3. Companions: nausea, sensitivity to light or noise, altered vision.
4. What happened before: sleep hours, last meal, caffeine, water, stress, cycle day.
5. Painkiller yes or no, which one and whether it worked.
6. Blood pressure if you have it, with both readings.

At the end of the month you will have three answers no test gives: how many days it hurts, how many days you medicate, and what usually happens before. With that, the appointment starts at the right question.