Tick paralysis

Douglas J Lanska MD FAAN MS MSPH (

Dr. Lanska of the University of Wisconsin School of Medicine and Public Health, the Medical College of Wisconsin, and IM Sechenov First Moscow State Medical University has no relevant financial relationships to disclose.

Originally released February 5, 2001; last updated October 21, 2020; expires October 21, 2023


Tick paralysis is a potentially fatal disease that causes rapidly ascending weakness, particularly in children. The condition resolves on removal of the offending tick. Every physician should keep tick paralysis in mind when confronted with a patient with rapidly progressive paralytic symptoms or ataxia.

Key points


• Tick paralysis should be suspected in anyone with potential tick exposure who has an acute, flaccid paralysis or ataxia.


• Clinical diagnosis is only secured by identifying an attached tick, with removal yielding rapid improvement.


• Tick paralysis is a noninfectious, neurotoxic process that is seen more in children than adults.


• The primary diagnostic confusion is with Guillain-Barré syndrome.

Historical note and terminology

Tick paralysis, also sometimes referred to as tick toxicosis, was first described in Australia in 1824 and in North America in 1912 (Stanbury and Huyck 1945); additional cases were subsequently described in Africa, Australia, and Mediterranean countries. The clinical features of ascending paralysis and resolution after finding and removing a tick were recognized in the initial descriptions. Early reports included descriptions of paralysis in both humans and animals. Early attempts to understand the mechanism of muscle weakness used intentional infestation of various animals; these efforts demonstrated considerable variability in susceptibility between species, with sheep, cattle, and cats and dogs most vulnerable.

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