• otulinum toxin type A;
  • chronic tension-type headache;
  • pericranial musculature;
  • intramuscular injection

Chronic tension-type headache is a common condition, the pathophysiology of which is not well understood. Over-activity of the pericranial muscles is thought to play a role, although sustained muscle contraction is probably a consequence, rather than a cause, of headache. Botulinum toxin type A (BTX-A) is useful in many conditions involving excessive muscle contraction and may therefore be effective in relieving the pain associated with this type of headache. To investigate the efficacy of BTX-A in relieving pain associated with chronic tension-type headache, a double-btind, randomised, placebo-controlled study was carried out, in which 37 patients received BTX-A, injected into the temporalis or cervical muscles of the neck. Clinical outcome was measured over a 4-month study period using headache diaries and chronic pain index scores. Patients treated with BTX-A showed an improvement in headache severity over the 4-month study period, with 13 out of 22 patients showing a 25, 50 or >50% improvement in headache score at Month 3 compared with two out of 15 patients in the placebo group. The number of headache-free days increased significantly in the BTX-A-treated patient group, and patients recorded an improvement in quality of life following BTX-A injection. It can be concluded that intramuscular injection of BTX-A is an effective treatment for chronic tension-type headache.