What are they like?

Rigors are episodes in which your temperature rises - often quite quickly - whilst you have severe shivering accompanied by a feeling of coldness ('the chills'). The fever may be quite high and the shivering may be quite dramatic.

When the shivery part of the rigor ends, things change quite quickly. The affected person (who now has a fever) will suddenly feel too hot. They will want to cool down, will look flushed and may sweat profusely. Gradually their body temperature will fall again. Rigors may occur only once in an illness, or can occur several times in a row.

Are they serious?

A rigor is not serious in itself, although it feels unpleasant. However, some of the causes of rigors are serious and some need immediate treatment. For this reason you should always seek medical advice if you or your child experience a rigor.

Is there anything else it could be?

The shivering, pale face and sensation of cold in the shivery phase of rigors are similar to the shivering, pale face and sense of cold patients experience when their body temperature is actually too low (hypothermia). You are unlikely to confuse the two, as a person with hypothermia will be cold to the touch, and their recent exposure to a cold environment is likely to be obvious. However the possibility of hypothermia should not be forgotten in someone who is shivering. Hypothermia can come on gradually in elderly people in their own homes, particularly during spells of cold weather.

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Dr Mary Lowth
Peer Reviewer:
Prof Cathy Jackson
Document ID:
29405 (v1)
Last Checked:
30 May 2017
Next Review:
26 June 2020

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.