Olfactory dysfunction in patients with cluster headache

Cluster headache (CH) is a primary headache characterized by strictly unilateral, short-lasting severe headache attacks accompanied by at least one ipsilateral autonomic symptom. Our study aimed to determine whether CH patients had olfactory dysfunction and to correlate it with clinical characteristics.

Twenty patients and 57 healthy volunteers were included in the study. All participants were examined in the otorhinolaryngology outpatient clinics to exclude other clinical problems causing olfactory dysfunction. The Sniffin' Sticks test was performed, and threshold (T), discrimination (D), identification (I) scores, and TDI global olfactory score were evaluated.

The CH patients had significantly lower threshold scores than healthy controls (6.9 ± 1.70 vs. 7.8 ± 1.08, p = 0.007). The mean threshold scores of CH patients during in-bout (n = 9) were significantly lower than CH patients during out-of-bout (n = 11) in subgroup analysis (5.9 ± 1.16 vs. 7.6 ± 1.76, p = 0.038). CH patients with left-sided headache had significantly lower discrimination scores compared to CH patients with right-sided headache (12.8 ± 1.24 vs. 14.4 ± 1.51, p = 0.03).

There is marked impairment in olfactory function in CH patients compared to healthy controls.