To study the phenotype and laterality of cranial autonomic symptoms (CAS) in a cohort of migraineurs, and to understand any associations with headache laterality and frequency.

CAS are usually associated with the trigeminal autonomic cephalalgias (TACs), although it is clear that they can also occur in migraine and are compatible with the diagnosis.

Migraineurs seen within our tertiary headache service between 2014 and 2018 were selected (n=340). Clinical information regarding age, disease duration, sex, headache frequency, headache diagnosis, headache laterality, CAS phenotype and laterality was acquired from the first consultation, during which a standardised detailed headache history is taken by a trained headache physician. Statistical analyses were performed to assess for an association between headache frequency and number of CAS and the relationship between headache laterality and CAS laterality.

The mean age at evaluation was 43 (range 14-94, SD 15), with a mean disease duration of 26 years (range 2-77, SD 14). The majority (84%) were female. The most common diagnosis was chronic migraine (78%) and aura was present in 54%. The median number of headache days a month was 26 (IQR 15-75). At least one CAS was reported in 74%. A median of two CAS were reported (IQR 0-3), with the most common being nasal congestion (32%), lacrimation (31%) and aural fullness (25%).  Most patients reported unilateral headache (80%) and strictly unilateral CAS (64%). There was a positive association between headache laterality and strict CAS laterality in the same individual (χ²₁20.7, P<0.001). There was a weak positive correlation between headache frequency at baseline and the total number of CAS reported in any individual (r=0.11, P=0.047).