Sweating: 'I get severe night sweats – and no one knows why'

I've been suffering for the past two or three years with severe night sweats. I am a 42-year-old man who is relatively healthy. My GP has sent me for an X-ray (to rule out TB, I think) which did not show anything abnormal. The GP is at a loss to provide me with any advice. This doesn't happen every night, although it does seem to be increasing in frequency.

Dr Fred Kavalier answers your health question:

There are certain symptoms that ring alarm bells for doctors, and night sweats is one of them. I am reassured by the fact that you seem to be healthy even though you have had these sweats for two or three years. TB is one possible cause, and it's good to know that your chest X-ray is normal. But not all types of TB show up on a chest X-ray.

Your doctor also needs to think about blood diseases, such as lymphoma or leukaemia, and unusual infections. Hormonal abnormalities, including an overactive thyroid and rare hormone-secreting tumours, also need to be considered. Another common cause of night sweats is too much alcohol. Talk to your GP about having more tests.

Readers write

VS, a dentist, gives some information on the lights that dentists use:

You said that dentists use UV light. We most certainly do not! The light we use is of a short wavelength, but absolutely not UV. We shield the rays with amber plastic simply due to the intensity of the light.

Please send your questions and suggestions to A Question of Health, 'The Independent', Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182 or e-mail to health@independent.co.uk. Dr Kavalier regrets that he is unable to respond personally to questions.