Ictal piloerection is associated with high-grade glioma and autoimmune encephalitis-Results from a systematic review

To comprehensively analyze ictal piloerection (IP) in a large number of subjects.

We performed a systematic review on case report studies of patients diagnosed with IP (1929-2017) with additional cases included from the Department of Neurology of University of Pécs, the National Institute of Clinical Neurosciences, and Odense University Hospital. Each included case was characterized regarding patient history, IP seizure characteristics, diagnostic work-up, and therapy. Comparative analyses were also carried out based on sex and pathology.

Altogether, 109 cases were included. We observed a strong male predominance (p < 0.001). The mean age at onset of epilepsy was 39.5 ± 20.7 years (median: 38, IQR:24-57). The seizure onset zone was temporal (p < 0.001), and was lateralized to the ipsilateral hemisphere in unilateral localization (p = 0.001). The seizure was accompanied by cold shiver in 53%, and by other autonomic symptoms in 47% of cases. In 53% of patients, IP never progressed into complex partial or generalized tonic-clonic seizure; 16% of the patients reported occasional, and 31% regular generalization. Seizure frequency was higher among females (median:25/day, IQR:3-60) than among males (median:3/day, IQR:1-11) (p = 0.017). The two most common underlying pathologies were limbic encephalitis (23%) and astrocytoma (23%, among them 64% WHO III-IV astrocytoma).

IP was particularly associated with autoimmune encephalitis and high-grade glioma, suggesting IP's particular clinical importance in directing diagnostic work-up.