Episodic Tension-type Headache: Diagnosis [Clinical Review Discussion]

The International Headache Society (IHS) has classified headaches into two broad categories, primary and secondary.  Primary headaches are headaches with no known organic cause and are classified into 4 groups 1) migraine  2) tension-type  3) cluster and 4) other primary headaches (1).  The subject of this paper, episodic tension-type headache (ETTH), is one of three sub-categories of tension-type headache.  The others being chronic tension-type headache and probable tension-type headache. 

The diagnosis of ETTH is established by ruling out other pathology and taking a thorough history.  The clinical characteristics of the headache pain are then evaluated in order to properly classify the headache type.

The following are the diagnostic criterion established by the IHS for ETTH (1): (Reproduced with permission of the International Headache Society)

Infrequent episodic tension-type headache (IHS: 2.1, ICD-10: G44.2)

Description:  Infrequent episodes of headache lasting minutes to days. The pain is typically bilateral, pressing or tightening in quality and of mild to moderate intensity, and it does not worsen with routine physical activity. There is no nausea but photophobia or phonophobia may be present.

Diagnostic criteria:

A.  At least 10 episodes occurring on <1 day per month on average (<12 days per year) and fulfilling criteria B-D

B.  Headache lasting from 30 minutes to 7 days

C.  Headache has at least two of the following characteristics:

1.  bilateral location
2.  pressing/tightening (non-pulsating) quality
3.  mild or moderate intensity
4.  not aggravated by routine physical activity such as walking or climbing stairs

D.  Both of the following:

1.  no nausea or vomiting (anorexia may occur)
2.  no more than one of photophobia or phonophobia

E. Not attributed to another disorder

Frequent episodic tension-type headache (IHS: 2.2. ICD-10: G44.2) 

Description:  Infrequent episodes of headache lasting minutes to days. The pain is typically bilateral, pressing or tightening in quality and of mild to moderate intensity, and it does not worsen with routine physical activity. There is no nausea but photophobia or phonophobia may be present.

Diagnostic criteria:

A.  At least 10 episodes occurring on <1 day per month on average (<12 days per year) and fulfilling criteria B-D below

B.  Headache lasting from 30 minutes to 7 days

C.  Headache has at least two of the following characteristics:

1.  bilateral location
2.  pressing/tightening (non-pulsating) quality
3.  mild or moderate intensity
4.  not aggravated by routine physical activity such as walking or climbing stairs

D.  Both of the following:

1.  no nausea or vomiting (anorexia may occur)
2.  no more than one of photophobia or phonophobia

E. Not attributed to another disorder

Comment:

Frequent tension-type headache often coexists with migraine without aura. Coexisting tension-type headache in migraineurs should preferably be identified by a diagnostic headache diary. The treatment of migraine differs considerably from that of tension-type headache and it is important to educate patients to differentiate between these types of headaches in order to select the right treatment and to prevent medication-overuse headache.

Additionally infrequent ETTH and frequent ETTH are each divided into tension-type headache associated with pericranial tenderness and tension-type headache not associated with pericranial tenderness.  

The reader should be aware that some authors question the IHS classification system.  They argue that migraine and ETTH may be the same entity with differences limited primarily to severity.  In support of this position Kaniecki (2) and Vargas (3) have observed that migraine and ETTH share common precipitating factors, clinical presentation, epidemiology and often co-occur in patients.  These similarities lead to the conclusion that these headache types may be “two points on a continuum” (3) rather than separate entities.