Constant Headache – Causes of Persistent, Continuous Headaches

What is a Constant Headache?

A headache is one of the more common symptoms experienced in life and is usually episodic. Constant headaches are considered as any head pain that does not subside for weeks or months. It can vary from severe pain to a dull ache. It may appear episodic but careful assessment will reveal that it is continuous (constant, persistent, non-stop, neverending). The the pain intensity may subside, although not resolve, for a period of time (hours or days) and then return to the full intensity.

These headaches may respond to analgesics (partial or complete pain relief), however, this does not change the nature of the headache – constant, continuous, persistent.

What is a Chronic Daily Headache?

A constant headache is not necessarily chronic in nature. Any headache, episodic or persistent, that lasts for a period of 3 months or more may be considered as chronic.

The term chronic daily headache is technically used for these types of headaches and the pain will usually be present for at least 15 days or more in a month. In order to conclusively diagnose a case of a chronic daily headache, it is advisable to keep a headache diary (record the frequency, possible trigger factors, day of menstrual cycle, pain intensity from 1 to 10 and duration) for a period of 3 to 6 months.

Clinical Significance of a Constant Headache

Any person suffering with a constant headache for a period of time may become frustrated. The continuous pain, range of tests and investigations and regular change in medication or the dosage can become tiresome. Questions arise as to whether a diagnosis is being missed or the focus on one possible cause is leading the clinician astray. Many medical practitioners will attribute a constant headache to psychological causes (depression, anxiety or imaginary) which leaves many a patient unsatisfied with the diagnosis.

A persistent headache without any neurological symptoms, no other obvious signs and symptoms or a lack of significant clinical findings of other disorders is unlikely associated with any serious medical disorder. Repeat tests, investigations and clinical evaluations by more than one medical practitioner is always recommended. This ensures that any developing condition is not missed either as a result of negative or inconclusive findings initially or due to a practitioner’s skill, or lack thereof.

A diagnostician may be required to work with your general practitioner and medical specialists (neurologist, physician, psychiatrist) in order to find the cause of the constant headache. Long term pain management may be the only option in dealing with a constant headache in some cases.

Causes of a Constant Headache

A continuous headache with no other significant signs or symptoms may be due to a number of causes. Associated features of the condition may be missed by the patient or practitioner or may appear at a later stage in the condition.

The conditions discuss below may account for constant headaches that have persisted for weeks or months, with NO signs and symptoms that would indicate a specific condition (neurological or other) and NO significant findings upon tests and investigations.

Tension-Type Headache

The most common cause of a constant headache is a tension-type headache (commonly referred to as tension headaches).  This type of headache may persist for weeks and in some cases, even for months. If it persists for more than 3 months, it may be considered as a chronic daily headache, or more specifically as a chronic tension-type headache.

While the trigger factors for tension-type headaches are common among sufferers, the exact cause is unknown. Two theories continue to persist about the possible cause :

  1. Increased muscle tension (head, neck and/or back muscles) as a result of overuse, strain or posture. Neck muscle spasm (also referred to as cervical muscle spasm) accounts for a large number of cases and the use of muscle relaxants, physical therapy and neck exercises appears to reduce the severity and temporarily resolve these type of headaches. It is possible that the muscle tension may not be a cause but a common feature found in most cases of tension-type headaches.
  2. Changes in brain hormones – serotonin, endorphins and other chemicals – for unknown reasons. These cases respond well to serotonin agonists like triptan, which was traditionally used for migraines and cluster headaches. The use of tricyclic antidepressants and selective-serotonin reuptake inhibitors prove to be effective in preventing a recurrence of these constant headaches. This does not mean that every case of a tension-type of headache is due to depression, anxiety, stress or other psychological causes.

NB : Excessive use of analgesics, particularly those containing codeine, will worsen this type of headache.

New Daily Persistent Headache

This is new category for primary headaches and is one of the types of chronic daily persistent headaches. It has features of migraines and tension-type headaches. The onset is sudden (over days, not minutes) and can persist for months, if not longer. There is some evidence to suggest that new daily persistent headaches may be linked to rebound headaches.

Rebound Headaches

These are headaches as a result of overuse of pain relieving medication. It is a vicious cycle as the sufferer tends to use analgesics in order to relieve the headache thereby perpetuating the pain. Other drugs like ergotamine which is used for migraines may also be responsible for rebound headaches.

Any chronic use of analgesics that is stopped for up to a week will often lead to improvment of the headache in a case of rebound headaches. The easy availability of OTC and scheduled analgesics plays a significant role in the increase of these type of headaches as the sufferer is often unable to understand the benefits of stopping analgesics or cannot tolerate the pain (headache) and has to use an analgesic.

Chronic Medication Headache

In these cases, a headache may be a side effect of a drug used to manage a chronic condition. The pain will persist until the medication is discontinued or replaced with other drugs.

Raised Intracranial Pressure

Any space-occupying pathology, whether a mass lesion (tumor, cyst) or fluid (cerebrospinal or edema), is referred to as raised intracranial pressure. When there is no mass present but raised intracranial pressure is due to poor drainage of CSF, this is known as idiopathic intracranial hypertension.

Raised intracranial pressure is often associated with a severe, sudden headache and serious neurological and other signs or symptoms like vomiting. However, this is not always the case especially in an instance where the increase in pressure is gradual (rising pressure). At times, a constant headache may be the first and only symptom present for a period of time before other signs and symptoms of raised intracranial pressure are evident.

There are certain features of a headache due to raised intracranial pressure :

  • Mild or dull headache which is continuous but responds well to analgesics.
  • Constant headache which is worse in the morning and improves through the day.
  • Pain worsens with bending forward, coughing and straining.

A sudden severe headache or ‘thunderclap’ headache is more likely due to a subarachnoid hemorrhage.

Facial Pain with Headache

There are a number of causes of head pain (head ~ face + cranium) but the most common causes include :

  • Temporomandibular TMJ dysfunction (jaw pain)
  • Dental pain
  • Sinusitis
  • Post-herpetic neuralgia
  • Atypical facial pain

Sometimes facial pain may be absent in these cases with just a headache persisting.

NB : Trigeminal neuralgia causes short episodes (not constant) of severe pain that is of a sudden onset.

CSF Leak and Post-Concussion Syndrome

CSF leak may be a slow leak of cerebrospinal fluid from a tear in the dura (outermost layer of the meninges surrounding the brain and spinal cord). Other symptoms like fluid from the ears and a runny nose may also be present. Trauma is a common cause.

Post-concussion syndrome may persist for prolonged periods after head trauma. Constant headaches may be present.

Age-Related Headache

This is more commonly seen in patients over the age of 60 years old. Giant cell arteritis, post-herpetic neuralgia, glaucoma and psychogenic causes should be investigated.

Hemicrania Continua

Although rare, hemicrania continua may be the cause of a continuous, one-sided headache and facial pain. The condition may be continuous, with daily headaches, or remitting, where the headache may last for up to 6 months.

In the latter form, there may be pain-free periods for weeks or months and then the headache recurs. Other signs and symptoms, usually one-sided, may often be present and it is common where this chronic condition is mistaken for other neurological and infectious causes of headaches.


While this term is used loosely for severe and/or constant headaches, a migraine is usually not persistent. There may be repeat episodes (intermittent) but a continuous headache for days or weeks is unlikely a migraine type of headache.

It is possible for migraine sufferers to experience other types of headaches which may be longer lasting between migraine attacks. This contributes to the perception of a continuous migraine lasting for weeks or months. Chronic migraine or transformed migraine are not usually responsible for persistent headaches lasting for weeks or months which do not subside.

Hypertension Headache

The debate surrounding the link between high blood pressure (hypertension) and headaches have been persisting for decades. Not every hypertension patient will experience headaches as a result of the high blood pressure. Refer to Headache and Hypertension (Medscape).

Other Causes

There are other causes of a constant headache with no other signs and symptoms evident.

  • Cervicogenic headaches
  • Occipital neuralgia
  • Brain aneurysms – ‘leaking’ aneurysms
  • Female hormone disturbances
  • Depression or anxiety
  • Abuse – physical, sexual, emotional
  • Alcohol abuse
  • Narcotic drug addition

Other Points to Consider

  • The presence of a fever should warrant further investigations for infections, particularly viral, where there is secondary headaches. Tropical infections should always be considered if there is a history of or onset after overseas travel.
  • Neurological conditions (or signs and symptoms) may present with secondary headaches and further investigations are necessary. Also refer to Headaches and Dizziness and Headache, Nausea and Vomiting.
  • Children complaining of headaches, whether constant or episodic, should always warrant further investigation. Children usually complain of abdominal pain, not headaches, as an attention-seeking mechanism.
  • Headaches in other chronic conditions like diabetes are a common feature.
  • Loss of weight, lack of appetite, fatigue and/or malaise with continuous headaches should not always be passed off as depression, even in the light of social and/or emotional circumstances. Many chronic and terminal conditions may present with only these signs and symptoms for long periods of time.

Causes of Chronic, Constant Severe Headache

  • Somatisation disorder: psychological problems may result in true or imaginary severe headache and other complaints
  • Temporal arteritis is an inflammation of the temporal artery. Symptoms include:
    • Chronic one-sided headache and extreme tenderness
    • Low-grade fever
  • Carotidynia is an inflammation of the carotid artery with (1):
    • One-sided throbbing pain and tenderness in the neck and head
  • Brain tumor or cystsymptoms may develop slowly over several months and may include:
    • Recurrent headaches, worse in the morning
    • Abnormal sensations and muscle weakness on one side of the body
    • Personality changes may develop slowly over several months
    • Slurred speech, vision disturbance or other neurological symptoms
  • Brain aneurysm, even if not ruptured, can cause:
    • Constant, moderate or severe headache
    • Nausea or vomiting
    • Blurred vision
    • Drooping eye

Severe Headache in Small Children

Causes of severe headache in small children include:

  • Citrullinemia – a genetic disorder of metabolism of amino acids. Symptoms include (2):
    • Severe headache, sleepiness, poor appetite, seizures
  • Hydrocephalus– a collection of the fluid that surrounds the brain due to a birth defect or as a complication of an infection, tumor, trauma. Symptoms:
    • Rapidly growing head
    • Eyes that seem to gaze downward
    • Prominent fontanelles
    • Irritability
    • Constant severe headache


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