Uhthoff's phenomenon or Uhthoff's sign is the temporary worsening of MS symptoms caused by an increase in temperature. It is usually applied to optic neuritis and other visual symptoms but can also refer to motor or sensory symptoms.
The condition named after Wilhelm Uhthoff, a German neuro-opthamologist, who first described it in 1890.
Last updated: December 2017
Last reviewed: January 2016
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