Increased muscular and cutaneous pain sensitivity in cephalic region in patients with chronic tension-type headache.

Increased excitability of the central nervous system generated by repetitive and sustained pericranial myofascial nociception may be responsible for transformation of episodic tension-type headache into chronic form. We aimed to compare mechanical and electrical (intramuscular and cutaneous) pain thresholds in trapezius and anterior tibial regions between 20 patients with chronic tension type headache and 20 healthy controls. Pain thresholds to three types of electrical stimulation (single pulse, 2 and 100 Hz) were significantly lower in patients than in controls in trapezius muscle (P < 0.02) and in skin overlying the trapezius muscle (P < 0.05), whilst electrical pain thresholds did not differ between groups in anterior tibial muscle and skin. Quantitative sensory testing revealed increased pain sensitivity in patients as assessed by pressure-controlled manual palpation (local tenderness score, LTS; P < 0.01) and by pressure algometry (mechanical pain thresholds; P < 0.05) in test areas over the trapezius muscle, but not the anterior tibial muscle. In summary, this study demonstrates lower pain thresholds in muscle and skin of the cephalic region but not in lower limb muscle and skin in patients with chronic tension-type headache than in healthy controls. Increased sensitivity in nociceptive pathways from cephalic region may be of importance in the pathophysiology of chronic tension type headache.