Chronic daily headache (CDH) is defined as headaches that occur for 15 days or more in a month, at least for 3 months. Therefore, it is not a diagnosis per se. 4% of the population is affected by CDH.
Short-duration chronic daily headache (CDH) are brief headache syndromes and trigeminal autonomic cephalalgias. They are relatively rare and only a small proportion of CDH patients are affected by them  .
The trigeminal autonomic cephalalgias have autonomic features with unilateral trigeminal distribution, these include paroxysmal hemicrania, chronic cluster headache, and short-lasting unilateral neuralgiform attacks with autonomic cranial symptoms or conjunctival tearing and injection.
Most cases with long-duration CDH are affected by migraines or tension-type headaches. Other types include new daily persistent headache and hemicrania continua .
Medication overuse further complicates treatment in two-thirds of patients who regularly use abortive medication such as acetaminophen, caffeine, non-steroidal anti-inflammatory drugs, triptans, and narcotics.
In tension-type headaches, bilateral or occipital bandlike discomfort build up in a slow way and can last for several days. Unlike migraines, nausea and photophobia are generally absent. If a headache becomes constant in 72 hours it is new daily persistent headache instead of chronic tension-type headache which develops more slowly.
New daily persistent headache is more refractory to treatment compared to chronic tension-type headache.
Patients who progress to CDH may have symptoms of both a migraine and tension-type headaches which result in a challenging treatment planning .
Entire Body System
If a headache becomes constant in 72 hours it is new daily persistent headache instead of chronic tension-type headache which develops more slowly. [symptoma.com]
METHODS: A Headache Center to characterize headaches in children (3 to 18 years old) was established. Over 34 months, 577 children have been evaluated. With use of a definition of or 15 headaches per month, 200 (34.6%) children had CDH. [ncbi.nlm.nih.gov]
The long-term goals of this study are to reduce the symptoms that are associated with recurrent headaches and to collect data that can be used for future acupuncture studies. [clinicaltrials.gov]
Headache disorders, characterized by recurrent headache, are among the most common disorders of the nervous system. [who.int]
Sustained or recurrent headaches can greatly impact school performance and may even induce behavioral disturbances. 1 Headache accounts for approximately 1% of all pediatric ED visits. 2,3 Fortunately, most headaches in children prompting an ED visit [accessmedicine.mhmedical.com]
If primary CDH is diagnosed, detection of the subtype is necessary to plan appropriate treatment accordingly.
Evaluation of red flags is important as they suggest a secondary etiology for a headache  .
Red flags and their suggestive etiologies:
- A headache that is aggravated or relieved by an upright or supine position: intracranial hemorrhage
- A headache provoked by the Valsalva maneuver: Arnold-Chiari malformation
- Sudden onset of a headache: Subarachnoid hemorrhage
- Onset after 50 years: Brain neoplasm
- Papilledema: Increased intracranial pressure
- Lateralizing or focal neurologic signs: Hemorrhagic stroke
- Systemic symptoms (fever, weight loss, myalgias): Meningitis, giant cell arteritis, encephalitis
- Recent pregnancy: Postpartum preeclampsia
Imaging studies must be ordered when red flags are observed . Magnetic resonance imaging (MRI) is considered the most useful method since it has a higher sensitivity to detect secondary causes of headaches compared to computed tomography (CT). In absence of contraindications, MRI with contrast should be ordered, especially when an intracranial mass is suspected. CT scans are more appropriate for acute settings to exclude intracranial mass or hemorrhage. Primary headaches do not have specific MRI findings.
- Headache Classification Subcommittee of the International Headache Society. The International Classification of Headache Disorders: 2nd edition. Cephalalgia. 2004;24(suppl 1):9–160.
- Matharu MS, Goadsby PJ. Trigeminal autonomic cephalgias. J Neurol Neurosurg Psychiatry. 2002;72 suppl 2:ii19–ii26.
- Halker RB, Hastriter EV, Dodick DW. Chronic daily headache: an evidence-based and systematic approach to a challenging problem. Neurology. 2011;76(7 suppl 2):S37–S43.
- Goadsby PJ, Boes C. Chronic daily headache. J Neurol Neurosurg Psychiatry. 2002;72 suppl 2:ii2–ii5.
- Dodick DW. Clinical practice. Chronic daily headache [published correction appears in N Engl J Med. 2006;354(8):884]. N Engl J Med. 2006;354(2):158–165.
- Wiendels NJ, Knuistingh Neven A, Rosendaal FR, et al. Chronic frequent headache in the general population: prevalence and associated factors. Cephalalgia. 2006;26(12):1434–1442.
- Stewart WF, Ricci JA, Chee E, Morganstein D, Lipton R. Lost productive time and cost due to common pain conditions in the US workforce. JAMA 2003;290(18):2443–2454.
- Lipton RB, Stewart WF, Scher AI. Epidemiology and economic impact of migraine. Curr Med Res Opin 2001;17(Suppl 1): s4-s12.