Massive tick (Ixodes holocyclus) infestation with delayed facial‐nerve palsy

A 48-year-old man with tick infestation was referred to our hospital emergency department by his general practitioner. The patient complained of lumps on his scalp (present over the previous few weeks), lethargy, myalgia, unsteadiness on his feet and numb lips. He stated that he spent a lot of time walking in bushland around his home. His friend’s dog had recently died from tick paralysis. Multiple engorged ticks were evident on the man’s face, scalp, neck, back and limbs. An engorged tick was removed from his left cheek, but there were no intra-aural or periaural ticks. He had multiple associated urticarial lesions and generalised lymphadenopathy. His pulse was 114 beats/ minute, blood pressure 148/100 mmHg and he had a temperature of 37.5 C. Neurological examination revealed no cranial-nerve deficits. In particular, there were no motor or sensory deficits of the face. The numbness of the lips, which the patient had earlier described, had now resolved. His gait, muscle power, tone and reflexes were normal. Light touch and pinprick sensations in his limbs were also normal. Forty-four ticks (41 females [32 engorged] and 3 males) were removed with forceps (see Box), carefully avoiding pressure on the ticks’ abdomen, which is thought to trigger expression of venom. The species was later formally identified as Ixodes holocyclus (Mr Bruce Dixon, Senior Microscopist, Olympus Imaging Unit, Parasite Identification and Diagnostics Program, Adelaide University, personal communication). In view of the magnitude of the infestation, the patient was asked to return the following morning for reassessment. A review 20 hours after tick removal revealed left facial-nerve palsy. In addition to the lower motor neurone motor deficit, the patient complained of altered sensation over his left cheek and upper lip, and subjective loss of light touch and pinprick sensation from the left cheek to the upper lip were demonstrated. As tick venom has not been shown to affect sensory-nerve conduction, the most likely explanation is that this apparent dysaesthesia is akin to that seen with idiopathic Bell’s palsy, in which patients commonly complain of altered sensation in what is purely a disorder of the motor neurone. The phenomenon appears to relate to altered proprioception. No other neurological abnormality could be detected and there were no residual ticks found after a thorough search. The facial paralysis took seven days to completely resolve. After two weeks the patient felt well and had resumed his previous activities. He was advised to ask a friend or relative to check him thoroughly for ticks after spending any time in the bush.