In patients with multiple sclerosis (MS), heat intolerance may cause a pseudoexacerbation, which is a temporary worsening of MS-related symptoms.
A temporary worsening of symptoms can also happen in patients with postural orthostatic tachycardia syndrome (POTS) and dysautonomia.
[citation needed] Excess thyroid hormone, which is called thyrotoxicosis (such as in cases of hyperthyroidism), is the most common cause.
[1][2] Other causes include: Treatment is directed at making the affected person feel more comfortable, and, if possible, resolving the underlying cause of the heat intolerance.
Cooling vests can be used as a preventative tool to reduce a person's body temperature or when symptoms present to feel more comfortable.