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Symptoms worse in heat or hot showers

Also called: Heat sensitivity, Uhthoff's phenomenon

Symptoms that worsen in heat or hot showers can happen with multiple sclerosis (MS). Symptoms usually improve once cool.

Common causesMS, heat intolerance
Usually serious?Usually not
Get checked ifNew nerve symptoms
If you think it's an emergency, call 911.Thinking about suicide? Call or text 988.

Overview

Heat can briefly worsen MS symptoms.

Overactive thyroid causes heat intolerance.

When to get medical care

Call 911Sudden weakness or trouble speaking.
Get care todaySymptoms that don't improve when cool.
See a doctor soonNew heat sensitivity.

Causes

Causes include MS and overactive thyroid.

OwieClear has pages on 0 conditions that can cause symptoms worse in heat or hot showers. Each shows how soon to get care.

What you can do at home

  • Stay cool.

Medicines

Depends on cause.

At the doctor

Tests depend on symptoms.

Questions you may be asked

  • Symptoms

The exam

A nerve exam.

Tests

  • MRI
  • Thyroid tests

Prevention

Stay cool.

  • Avoid overheating

Check your symptoms

Most symptoms have more than one possible cause. The symptom checker looks at all of your symptoms together, plus your age, and shows how soon to get care.

Start the symptom checker

Sources

Last updated 2026-11-13.