The red ear syndrome and migraine: the role of the parasympathetic system in a complex and intriguing clinical association

Background and aims: The red ear syndrome (RES) is a rare syndrome characterized by burning pain and cutaneous erythema in the ear. It is probably due to an autonomic dysfunction, because of a hypofunction of sympathetic and/or a hyperactivity of parasympathetic control. We have previously described an intriguing association with migraine. In the present study, we have investigated the pathophysiological links between the RES and the clinical features of migraine, and pointed out the crucial role of the parasympathetic system. Methods: A total of 172 young migraine sufferers (92 M and 80 F, aged 4–17 years) underwent a clinical and instrumental evaluation. A semi-structured interview about their headache and the presence of the RES was administered. Results: We found the RES in 40 patients affected by migraine [23.25% (CI 17–29.5)]. The univariate statistical analysis showed a statistically significant association of the RES with: male gender (OR 2.1, 95% CI 1–4.5; p = 0.04), throbbing quality of the pain (OR 2.5, 95% CI 1–6.3; p = 0.04), vomiting (OR 2.5, 95% CI 1.2–5.1; p = 0.02), and phonophobia (OR 2.8, 95% CI 1–7.8; p = 0.03). It was confirmed by a multivariate stepwise logistic regression model only for throbbing pain [OR 2.7 (CI 1.1–6.7); p = 0.04], while male gender [OR 2.1 (CI 1–4.7); p = 0.05] and vomiting [OR 2.5 (CI 1–4.5); p = 0.05] were almost within significance level. Conclusions: The evidence of an association of the RES with some migraine features partially provoked by the parasympathetic system supports the hypothesis of a shared pathophysiological background (for example, via the activation of the trigeminal-autonomic reflex).