Uhthoff’s phenomenon (also known as Uhthoff’s syndrome, Uhthoff’s sign, and Uhthoff’s symptom) is the worsening of MS symptoms when the body gets overheated, whether it be from hot weather, exercise, fever, or saunas and hot tubs.

The condition named after Wilhelm Uhthoff, a German neuro-opthamologist, who first described it in 1890.

Uhthoff’s is only temporary, so there’s no need to panic if you develop symptoms. But if your vision is seriously impaired, ask someone to assist you.

MS-related heat sensitivity doesn’t cause new symptoms, but it can aggravate existing symptoms.

Treatment involves cooling your body temperature. Fever can also cause Uhthoff’s. When you have a fever, the remedy is to treat the underlying cause.

Our MS in a Minute videos were created to provide fast and factual definitions of commonly used terms in MS.

More resources:

• Feeling the heat with MS (MS Research Australia)
• Heat sensitivity information (MS Australia)
• Heath sensitivity in MS (MS Research Australia)
• The power of keeping cool (MS Australia)