Localizing value of cutaneous ictal phenomena: A systematic review

Area of Science:

• Neurology
• Epilepsy Research
• Autonomic Nervous System

Background:

• Clinical observation of autonomic signs during seizures can aid in localizing the epileptogenic zone (EZ).
• Ictal cutaneous phenomena, including piloerection, sweating, pallor, and flushing, are potential indicators of seizure origin.
• Understanding these signs is crucial for presurgical evaluation in focal epilepsy.

Purpose of the Study:

• To systematically review and meta-analyze the localizing value of ictal cutaneous phenomena in focal epilepsy.
• To evaluate the relevance of these signs in presurgical epilepsy evaluation.
• To determine the diagnostic utility of piloerection, sweating, pallor, and flushing for EZ localization.

Main Methods:

• Systematic literature search of PubMed and EMBASE following PRISMA guidelines up to June 1, 2025.
• Inclusion of studies reporting spontaneous ictal cutaneous signs identified via video-EEG in focal epilepsy patients.
• Risk of bias assessment (QUADAS-2), EZ localization confidence, and certainty of evidence (GRADE) evaluation; meta-analysis performed where data allowed.

Main Results:

• Piloerection showed high evidence for temporal lobe involvement (92%).
• Ictal pallor was strongly associated with temporal lobe epilepsy (76.9%), with left-sided lateralization and favorable surgical outcomes.
• Flushing indicated posterior quadrant involvement (High GRADE evidence), while sweating's localization was limited by heterogeneity and surgical validation.

Conclusions:

• Ictal cutaneous symptoms, particularly piloerection and pallor, are valuable "red flags" for temporal lobe epilepsy.
• Flushing is indicative of a posterior quadrant origin, supporting multimodal EZ localization.
• Despite limitations of retrospective case reports, these autonomic signs offer significant utility in epilepsy localization.