Tick paralysis is a loss of muscle function that results from a tick bite.
Causes, incidence, and risk factors
Hard- and soft-bodied female ticks are believed to make a poison that can cause paralysis in children. Ticks attach to the skin to feed on blood. It is during this feeding process that the toxin enters the bloodstream.
The paralysis is ascending -- that means it starts in the lower body and moves up. It is similar to that seen in Guillain-Barre syndrome and opposite that seen in botulism and paralytic shellfish poisoning.
Children with tick paralysis develop an unsteady gait (ataxia) followed several days later by weakness in the lower legs that gradually moves up to involve the upper limbs.
The child may also have mild, flu-like symptoms (muscle aches, tiredness).
Signs and tests
The person will have been exposed to ticks in some way. For example, he or she may have been on a recent camping trip, live in a tick-infested area, or have dogs or other animals that can pick up ticks. Often the tick is found only after thoroughly searching the person's hair.
Finding a tick embedded in the skin and noting above symptoms confirms the diagnosis. No other testing is required.
Removing the tick removes the source of the neurotoxin. Recovery is rapid following the removal of the tick.
Full recovery is expected following the removal of the tick.
If your child suddenly becomes unsteady or weak, have the child examined promptly. Breathing difficulties require emergency care.
Use insect repellents and protective clothing when out in tick-infested areas. Carefully check the skin after being outside and remove any ticks.
As a rule, if children are discovered to have ticks, it is a good idea to write the information down and keep it for several months. Many tick-borne diseases do not show symptoms immediately, and the incident may be forgotten by the time a child becomes sick with a tick-borne disease.
Diaz JH. Ticks, including tick paralysis. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 297.
Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.