Piloerection

Abstract: Purpose Ictal piloerection is an infrequent seizure semiology that is commonly overlooked as an ictal epileptic manifestation. Piloerection is considered to be principally caused by temporal lobe activity although frontal and hypothalamic seizure origins have been reported. The described etiology has shown a wide variety of structural causes such as mesial temporal sclerosis, tumors, posttraumatic, cavernomas and cryptogenic epilepsies. Methods We retrospectively reviewed the incidence of ictal piloerection in the clinical records of patients who underwent video-EEG monitoring (VEEGM) between 2007 and 2013 in a multicenter cooperative study. All patients presented refractory epilepsies and were evaluated with a protocol that included brain MRI, neuropsychology and VEEGM. Results A total of 766 patients were evaluated in four tertiary centers in Spain. Five patients showed piloerection as principal seizure semiology (prevalence 0.65%). The mean age at seizure onset was 39.6 years and the average epilepsy duration was 5.2 years (range 2–14) before diagnosis. Four patients were additionally examined with FDG-PET and/or SPECT-SISCOM. All presented temporal lobe epilepsy (TLE), three right-sided and two left-sided. A typical unilateral hippocampal sclerosis was described in 3 cases. The etiology detected in all cases was limbic encephalitis. Three had LGI1, one anti-Hu, and another Ma2 antibodies. Conclusion Our series describes a so far not well-recognized autoimmune association of pilomotor seizures to limbic encephalitis. This etiology should be ruled out through a comprehensive diagnostic work-up even in cases of long-lasting TLE with typical hippocampal atrophy on MRI.

Abstract: The insulating properties of the primate integument are influenced by many factors, including piloerection, which raises the hair and insulates the body by creating motionless air near the skin's surface. The involuntary muscles that control piloerection, the musculi arrectores pilorum (MAP), are mostly absent except on the tail in most strepsirhines, and are entirely absent in tarsiers and some lorisids. The absence of piloerection and the reduced effectiveness of pilary insulation in preventing heat loss affected the evolution of behavior and metabolic thermoregulation in these animals. In lemurs, this situation contributed to the use of positional and social behaviors such as sunning and huddling that help maintain thermal homeostasis during day-night and seasonal temperature cycles. It also contributed in many lemurs and lorises to the evolution of a wide variety of activity patterns and energy-conserving metabolic patterns such as cathemerality, daily torpor, and hibernation. The absence of functional MAP in strepsirhines and tarsiers implies the absence of effective piloerection in early primates, and the reacquisition of whole-body MAP in ancestral anthropoids prior to the separation of platyrrhine and catarrhine lineages.

Abstract: Background Cutaneous autonomic function can be quantified by the assessment of sudomotor and vasomotor responses. Although piloerector muscles are innervated by the sympathetic nervous system, there are at present no methods to quantify pilomotor function. Objective To quantify piloerection using phenylephrine hydrochloride in humans. Design Pilot study. Setting Hospital-based study. Participants Twenty-two healthy volunteers (18 males, 4 females) aged 24 to 48 years participated in 6 studies. Interventions Piloerection was stimulated by iontophoresis of 1% phenylephrine. Silicone impressions of piloerection were quantified by number and area. The direct and indirect responses to phenylephrine iontophoresis were compared on both forearms after pretreatment to topical and subcutaneous lidocaine and iontophoresis of normal saline. Results Iontophoresis of phenylephrine induced piloerection in both the direct and axon reflex–mediated regions, with similar responses in both arms. Topical lidocaine blocked axon reflex–mediated piloerection post-iontophoresis (mean [SD], 66.6 [19.2] for control impressions vs 7.2 [4.3] for lidocaine impressions; P 2 vs 7.2 [3.9] cm 2 ; P Conclusions Phenylephrine provoked piloerection directly and indirectly through an axon reflex–mediated response that is attenuated by lidocaine. Piloerection is not stimulated by iontophoresis of normal saline alone. The quantitative pilomotor axon reflex test (QPART) may complement other measures of cutaneous autonomic nerve fiber function.