Indications and Clinical Considerations
Greater auricular nerve block is useful in the diagnosis and treatment of painful conditions subserved by the greater auricular nerve including greater auricular neuralgia, red ear syndrome, and pain secondary to acute herpes zoster and postherpetic neuralgia ( Figure 14-1 ). This technique is also useful in providing surgical anesthesia and postoperative pain relief for patients undergoing external ear surgery when combined with lesser occipital nerve block.
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 ( Box 14-1 ). 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.
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Cluster headache
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Paroxysmal hemicranias
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Chronic
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Episodic
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Short-lasting unilateral neuralgiform headache
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Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT)
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Short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA)
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Long-lasting autonomic symptoms with hemicrania (LASH)
As its name implies, the pathognomonic finding of red ear syndrome is in fact a unilateral red ear (see Figure 14-1 ). 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. 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.
Clinically Relevant Anatomy
The greater auricular nerve is the largest sensory branch of the cervical plexus, arising from the fibers of the primary ventral ramus of the second and third cervical nerves. At a point just inferior and lateral to the lesser occipital nerve, the greater auricular nerve pierces the cervical fascia and passes superiorly and forward and then curves around the sternocleidomastoid muscle at Erb’s point ( Figure 14-2 ). The greater auricular nerve then pierces the superficial cervical fascia to move more superiorly and superficially to provide cutaneous sensory innervation to both surfaces of the auricle, the external auditory canal, angle of the jaw, and the skin overlying a portion of the parotid gland ( Figure 14-3 ).
