Comparison of generalized and localized hyperalgesia in patients with recurrent headache and fibromyalgia.

OBJECTIVES Research suggests that dysregulated pain modulation may play an important role in recurrent headaches and fibromyalgia syndrome (FMS). The primary objective of this study was to investigate algesic responses in localized cervical and pericranial regions (ie, headache-specific areas) and distal locations (ie, trochanter and gluteal) in patients with primary headaches (tension-type and migraine). The headache patients' algesic responses were compared with those of a sample of patients with musculoskeletal pain who report generalized hyperalgesia, or FMS. METHODS Seventy patients with mixed headache diagnoses and 66 patients with FMS underwent a standardized examination of generalized hyperalgesia based on American College of Rheumatology criteria. RESULTS Twenty-eight of the 70 headache patients reported the presence of widespread TP pain, suggesting generalized hyperalgesia. Headache diagnosis was unrelated to the presence or absence of generalized hyperalgesia. The subset of headache patients with generalized hyperalgesia did not differ from the FMS patients in pain sensitivity in the cervical and pericranial areas. Regression analyses revealed that pressure pain sensitivity was significantly related to self-reported pain only in the headache patients with generalized hyperalgesia. CONCLUSIONS These results suggest that extensive dysregulation in pain modulation is important for a substantial minority of recurrent headache patients, who seem to be quite similar to FMS patients. Differential treatment planning targeting generalized hyperalgesia may be useful in treating headache patients exhibiting generalized hyperalgesia more effectively.