The Clinical Syndrome
Red ear syndrome is an uncommon primary pain disorder thought to be a variant of one of a group of three headache syndromes known as the trigeminal autonomic cephalgias ( Table 19.1 ). Whether red ear syndrome is in fact a distinct pain syndrome resulting from auriculo-autonomic dysfunction or simply a constellation of symptoms that occurs on a continuum along with the other trigeminal autonomic cephalgias is a point of ongoing debate among headache and pain management specialists. As with most headache and facial pain syndromes, the exact cause of the pain of red ear syndrome is unknown; however, the pathogenesis of this uncommon cause of head and face pain is thought to be dysfunction of the trigeminal autonomic reflex. The rapid onset of ear redness and associated pain may be caused by an antidromic release of vasoactive peptides from the terminal afferent fibers of the third cervical nerve root, which provides sensory innervations to the pinna of the ear.
As its name implies, the pathognomonic finding of red ear syndrome is in fact a unilateral red ear ( Fig. 19.1 ). This redness involves the entire ear, including the pinna, and is associated with neuralgia-like pain reminiscent of sudden unilateral neuralgiform conjunctival injection tearing (SUNCT) headache (see Chapter 8 ). The pain and erythema associated with red ear syndrome have a rapid onset to peak, with attacks lasting 15 seconds to 5 minutes and the frequency of attacks ranging from 20 to 200 attacks per day. In some patients, these attacks can be triggered by sensory stimulation of the affected area, such as when brushing the hair. Although in many ways similar to SUNCT headache (i.e., unilateral, rapid onset to peak, short duration of attacks, pain-free periods between attacks), many dissimilarities also exist, including the location and pronounced autonomic phenomenon manifested by the red ear.
Signs and Symptoms
Patients with red ear syndrome present with the complaint of severe paroxysms of sudden onset of unilateral ear redness associated with pain involving the ipsilateral ear ( Fig. 19.2 ). The pain is neuralgiform in quality and severe to excruciating in intensity. Like trigeminal neuralgia, the pain of red ear syndrome rarely switches sides. Red ear syndrome occurs slightly more frequently in males. It can occur at any age, with a peak incidence in the fifth decade.