Individuals with vs without cluster headache were found to have lower cranial and extracranial pressure pain thresholds (PPTs), indicating central sensitization, according to a study published in Pain Medicine.
Although central sensitization and its clinical markers — allodynia, hyperalgesia, and temporal summation (TS) — have been documented in some headache disorders and suggested as possible mechanisms in cluster headache, few studies have examined this hypothesis.
In this cross-sectional study, 20 adults with cluster headaches (60% and 40% with episodic and chronic headache, respectively; 55% with left-sided headache; median age, 37.5; 85% men; median disease duration, 14 years; median attack frequency, 1.5 per day; median pain intensity, 8/10; 70% taking preventive medications) and 16 healthy controls age 18 to 65 years (median age, 37; 81.3% men)with normal brain magnetic resonance imaging results were enrolled between September 2016 and June 2017.
Participants completed a general questionnaire regarding demographic and clinical information, as well as the Hospital Anxiety and Depression Scale (HADS), the Beck Depression Inventory (BDI), the State-Trait Anxiety Inventory (STAI), the 36-Item Short Form Health Survey (SF-36), the Headache Impact Test (HIT-6), and the Allodynia Symptom Checklist (ASC). Participants then underwent bilateral trigeminal and extra-trigeminal PPT and perceptual wind-up ratio testing to assess temporal summation of pain.
Participants with vs without cluster headache had lower PPTs at all locations (P <.001 at all points tested), but comparable wind-up ratios (P >.05). Regarding psychological factors, there were significant differences between patients with cluster headache and control participants on the HADS, BDI, STAI, SF-36, and ASC (P <.01 for all), as well as on the HIT-6 (P <.001).
There was a moderate negative correlation in the control group between BDI and SF-36 (p = −0.59; P =.03). In the cluster headache group, there was a strong positive correlation between HADS and attack duration (p = 0.86; P <.01), and between HADS and BDI (ρ = 0.75; P <.01). A moderate negative correlation was established between BDI and attack frequency (ρ = −0.52; P =.03), between SF-36 and HADS (ρ = −0.64; P =.03), between BDI and SF-36 (ρ = −0.53; P =.02), SF-36 and HIT-6 (ρ = −0.58; P <.01), and between attack intensity and PPT over symptomatic (ρ = −0.66; P <.01) and asymptomatic (ρ = −0.65; P <.01) supraorbital nerves.
Study limitations include the use of a non-validated ASC and the small sample size.
“The results obtained in previous studies evaluating central sensitization in patients with [cluster headache] coincide with the results of the present study, and they support the main hypothesis that confirms the presence of central sensitization in patients with [cluster headache],” noted the authors. “These findings increase our knowledge of [cluster headache] and emphasize the importance of a multidisciplinary approach to treating these patients.”
Gil-Martínez A, Navarro-Fernández G, Mangas-Guijarro MÁ, Díaz-De-Terán J. Hyperalgesia and central sensitization signs in patients with cluster headache: a cross-sectional study. Pain Med. April 2019:1-9. doi:10.1093/pm/pnz070