History and exam
Key diagnostic factors
common
underlying primary headache disorder
MOH is a chronic secondary headache disorder attributable to overuse of acute medications by a person with a pre-existing primary headache.[1][10]
Migraine is the underlying primary headache condition in around 80% of patients with MOH.[27][28] Up to 90% of patients with MOH have a history of either migraine or tension-type headache or both.[2][3][4]
Adults newly diagnosed with MOH have had a diagnosis of the underlying headache disorder for an average of 20 years.[10] The peak prevalence of MOH occurs in the 50-60 years age group.[9]
Make a diagnosis of MOH if the patient meets all three of the criteria set out in the 2018 International Classification of Headache Disorders (ICHD-3):[1]
Headache on ≥15 days per month on a background of a pre-existing primary headache disorder.
Regular overuse for >3 months of acute treatments (at any dose) for the pre-existing headache disorder. Overuse is defined by: use of simple analgesics on ≥15 days per month (paracetamol, aspirin, or other non-steroidal anti-inflammatory drug [NSAID], alone or in any combination); or use of a triptan, opioid, or ergot derivative on ≥10 days per month; or use of a combination of analgesics from different classes on ≥10 days per month.
No other ICHD-3 headache diagnosis better accounts for the symptoms.
Make the diagnosis of MOH in addition to the diagnosis of the underlying headache disorder.[1]
headache on ≥15 days per month
MOH is defined by a headache occurring on ≥15 days per month in a patient who has been overusing acute medication for a pre-existing primary headache disorder (almost always migraine and/or tension-type headache [TTH]) and who has no red flags or other symptoms or signs to suggest an alternative diagnosis.[1]
Consider the possibility of MOH in any patient with a primary headache disorder who reports that an episodic headache has increased in frequency over time to become chronic (occurring on more days than not) and is associated with frequent use of single or combination acute medication.
The typical history is a background of migraine that has increased in frequency and/or severity over months or years, accompanied by escalating use of acute or symptomatic medication, which leads to a transition from an episodic to a chronic pattern of headache.[5][6]
The features of the headache vary widely and can be affected by the primary underlying headache and the type of medication that is being overused.[27] One prospective study found that patients with migraine and/or TTH who overused analgesic medication were more likely to develop a dull, diffuse, holocranial headache without migrainous symptoms. In contrast, those who overused triptans for underlying migraine were more likely to develop a daily migrainous headache (unilateral pulsating headache with autonomic disturbances).[32]
Only make a diagnosis of MOH if the patient meets the other two criteria set out in the 2018 International Classification of Headache Disorders (ICHD-3) (in addition to having a headache on ≥15 days per month on a background of a pre-existing primary headache disorder):[1]
Regular overuse for >3 months of acute treatments (at any dose) for the pre-existing headache disorder. Overuse is defined by: use of simple analgesics on ≥15 days per month (paracetamol, aspirin, or other non-steroidal anti-inflammatory drug [NSAID], alone or in any combination); or use of a triptan, opioid, or ergot derivative on ≥10 days per month; or use of a combination of analgesics from different classes on ≥10 days per month.
No other ICHD-3 headache diagnosis better accounts for the symptoms.
overuse of acute headache medication for >3 months
To receive a diagnosis of MOH, a patient must have been overusing acute medication for >3 months for symptomatic management of a primary headache disorder (almost always migraine and/or TTH).[1]
The overuse of acute/symptomatic medication is accompanied by a transition from an episodic to a chronic pattern of headache.[5][6]
Overuse is defined by:[1]
Use of simple analgesics on ≥15 days per month (paracetamol, aspirin, or other non-steroidal anti-inflammatory drug [NSAID], alone or in any combination), or
Use of an triptan, opioid, or ergot derivative on ≥10 days per month, or
Use of a combination of analgesics from different classes on ≥10 days per month.
Common medications associated with MOH are triptans, ergot derivatives, simple analgesics (including paracetamol or aspirin and other NSAIDs), opioids, barbiturates, or benzodiazepines.[27]
A cross-sectional survey of 13,649 US adults with migraine found that medication overuse was more common in those using triptans, opioids, and barbiturates and less likely in those using NSAIDs.[2]
Some evidence suggests that MOH develops over a shorter period when triptans, opioids, or combination analgesics are overused compared with simple analgesics.[27][32]
Bear in mind that the individual may be overusing >1 medication.[27] If the patient is using multiple drug classes for acute, symptomatic treatment of the underlying headache, they can be diagnosed with MOH if acute medication is being used on ≥10 days/month, even if no individual drug class is being overused.[1]
Be aware that MOH can develop in a patient with an episodic primary headache who uses pain medication for a different condition such as arthritis (rather than for the primary headache disorder).[27]
Only make a diagnosis of MOH if, in addition to overuse of acute medication, the patient also meets the other two criteria set out in the 2018 International Classification of Headache Disorders (ICHD-3):[1]
Headache on ≥15 days per month on a background of a pre-existing primary headache disorder
No other ICHD-3 headache diagnosis better accounts for the symptoms.
Other diagnostic factors
common
normal neurological examination
absence of red flag symptoms and/or signs
Check for any red flags in the history or on examination that should raise suspicion of an alternative cause of secondary headache. These include:[40][41]
Abnormal neurological symptoms: could be suggestive of a variety of conditions that need to be ruled out, such as brain tumour, brain abscess, spontaneous intracranial hypotension, cerebral venous sinus thrombosis.
Headache aggravated by postural changes or Valsalva manoeuvre: may be a feature of intracranial hypertension or hypotension.
Systemic symptoms or features, such as fever or weight loss. Fever could indicate a secondary headache attributable to infection, particularly if the patient has a history of HIV or other immunosuppression. Weight loss might be a symptom of malignancy.
A history of cancer: potential for brain metastasis.
Papilloedema on ophthalmological examination (idiopathic intracranial hypertension [also known as pseudotumor cerebri] or brain tumour).
Visual field defect (pituitary tumour).
Neck tenderness with limited range of motion (cervical myofascial pain syndrome).
Localised pain, induration, tenderness, or erythematous nodules over or along both temporal arteries (giant cell arteritis, especially if >50 years of age).
Jaw tenderness (temporomandibular joint disorder).
Joint hypermobility (spinal cerebral spinal fluid leak).
Orthostatic tachycardia (postural orthostatic tachycardia syndrome).
Pregnancy or puerperium: exclude pre-eclampsia, cerebral sinus thrombosis, hypothyroidism, anaemia, gestational diabetes.
Risk factors
strong
migraine as the underlying primary headache disorder
female sex
MOH is more common in women than in men. A prospective longitudinal study of 25,596 individuals in Norway with an 11-year follow-up found that female sex was associated with a 1.9-fold increased risk of MOH compared with male sex (95% CI 1.4 to 2.6), and an epidemiological survey of 44,300 randomly selected women in Sweden reported a female-to-male ratio of 2.8:1.[4][16]
use of opioid, barbiturate, triptan, or ergot derivative
Studies have shown that individuals who use simple analgesics as acute medication for their primary headache are at lower risk of developing MOH than those who use opioids, barbiturates, triptans, or ergot derivatives.[2][3][4][29]
In one US-based longitudinal study of 8219 individuals with episodic migraine who were followed for 5 years, the use of opioids or barbiturates was associated with a higher risk of transitioning to chronic migraine (odds ratio [OR] for barbiturate use compared with paracetamol use: 2.06, 95% CI 1.3 to 3.1; OR for opioid use compared with paracetamol: 1.98, 95% CI 1.4 to 2.2).[3]
A prospective longitudinal 11-year follow-up study of 25,596 individuals in Norway found a 5-fold increased risk for developing MOH among individuals who at baseline had reported regular use of tranquillisers compared with those who had not (OR 5.2, 95% CI 3.0 to 9.0).[4]
Other studies have found that frequent use of opioids was associated with a 2.3-fold increased risk for MOH (95% CI 1.3 to 3.9).[2][29]
Another longitudinal study of 13,649 US adults with migraine found that, compared with those not overusing medications, patients with medication overuse were more likely to be taking triptans (31.3% vs. 14.2%), opioids (23.8% vs. 8.0%), barbiturates (7.8% vs. 2.7%), or ergot derivatives (3.1% vs. 0.6%).[2]
anxiety and/or depression
Depression and anxiety are strong independent risk factors for chronification of the primary headache, which can lead in turn to medication overuse. They are the most frequent comorbidities among patients with MOH.[9][17][30] A prospective longitudinal 11-year follow-up study of 25,596 individuals in Norway found a twofold increased risk of MOH among individuals who at baseline had Hospital Anxiety and Depression Scale (HADS) scores ≥11 compared with those whose scores were ≤7. There was a 4.7-fold increased risk of MOH among those who had a combination of HADS scores ≥11 together with chronic musculoskeletal and gastrointestinal complaints (OR 4.7, 95% CI 2.4 to 9.0).[4]
weak
chronic musculoskeletal disease
A prospective longitudinal 11-year follow-up study of 25,596 individuals in Norway found that chronic musculoskeletal disease alone was associated with a 1.9-fold increased risk of MOH (95% CI 1.4 to 2.7).[4]
Note that MOH can develop in a patient with an episodic primary headache who uses pain medication for a condition such as arthritis (rather than for the primary headache disorder).[27]
chronic gastrointestinal disease
A longitudinal 11-year follow-up study of 25,596 individuals in Norway found that gastrointestinal disease alone was associated with a 1.6-fold increased risk of MOH (95% CI 1.1 to 2.2).[4]
low-level education
In a prospective longitudinal study of 25,596 individuals in Norway, over the 11-year follow-up period low-level education was found to be a risk factor for developing MOH. Low educational level was associated with a 1.9-fold increased risk (95% CI 1.2 to 3.0) when compared with high educational level.[4]
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