Hyperhidrosis, sweating and body odour (smell)

Sweat by itself does not smell.  It is merely salty water. However, as we all know, some people who sweat profusely do smell.  There can be several causes for this. 

Firstly, if you sweat regularly into clothes, the clothes themselves can start to smell with a combination of rotting fabric and bacteria.  Each time they get wet again, if they have not been cleaned thoroughly, the smell can worsen.

There can be bacterial overgrowth of the skin.  Microorganisms (bacteria) love warm, wet areas.  As such, people who sweat profusely, particularly if they do not wash regularly, can end up with a lot of bacteria on the skin which can produce a body odour. 

In the skin, there are other glands called eccrine glands that produce sebum.  Sebum is a greasy substance that lubricates the skin.  These glands are not the same as the sweat glands that just produce water with salts in it.  Some skins produce sebum which has a distinctive odour and, when mixed with the sweat, can cause quite a powerful aroma. 

Investigations of hyperhidrosis

If someone suffers from hyperhidrosis or excessive sweating, the first thing that is important is to check the medical history.  What this means is finding out exactly what the trigger points for sweating are, whether it is embarrassment, anger, fear, certain situations, or whether it is a constant problem.  It is also important to know whether it started recently or whether it has been a long term problem.  It is important to know if other members of the family have had a similar problem.  It is also important to know whether the hyperhidrosis comes on suddenly or is associated with a very fast heartbeat.

Many of these questions will indicate to a doctor that there might be an underlying medical condition. 

Examination of patients for hyperhidrosis is usually fairly simple.  Shaking the patient’s hand lets you know whether they have palmer hyperhidrosis – the palm is soaking wet!.  Examination of the underarms and clothes can tell whether there is really excessive axillary sweating.  Examining the pulse can point towards anxiety or thyrotoxicosis and examining the neck can also point towards thyroid disease.  The general appearance can show if a patient is overweight which, of course, can lead to increased sweating and also it can be seen whether the patient is dressing appropriately for the weather conditions.  Some people get so concerned about their hyperhidrosis that they over-dress, trying to hide the sweat marks, making themselves hotter and thereby worsening the condition.

People who suffer from hyperhidrosis should probably have their blood taken to test for thyroid disease as an over-active thyroid needs to be treated and will of course improve, if not cure, any hyperhidrosis.

Also, it would be sensible to perform 24 hour urine tests for phaeochromocytoma and carcinoid syndrome.  These conditions show up by the breakdown products which are released into the urine.  By collecting this over twenty-four hours, scientists are able to tell doctors whether excessive amounts of adrenaline, noradrenaline, dopamine (like adrenaline and noradrenaline), or serotonin (5HT) are being produced.