Many types of headache are characterized by their pattern of occurrence. The classification in, for example, episodic and chronic headache type is based on the number of headache days per month. The treatment of the headache is also based on the frequency of headache days per month.
Headaches caused by overuse of pain medication or triptans must always be considered if acute medication was necessary on more than 10 days per month no matter which dose was used. The “10-20 rule” is useful to avoid and recognize medication overuse headaches (MOH): pain medication and specific medication for migraines, so-called triptans, should be taken on 10 days a month at the most. On 20-30 days, no such medication should be taken. This rule only counts the days when such medication was taken, not the number of pills, the dose is irrelevant. This also means: it is better to treat the headache properly once than to persistently treat it a little bit. For this reason, it is essential to monitor the headache days per month as this allows to plan the correct therapy.