For those who suffer from excessive sweating, there are ways of alleviating the embarrassment, writes Eoin Burke-Kennedy
IT HAS long been observed that some people sweat more than others for no apparent reason.
Scientists believe people who sweat heavily may simply have larger sweat glands, making them more sensitive to the nerve stimuli which trigger perspiration.
But for a significant minority, excessive sweating or hyperhidrosis, as it is known medically, represents a serious problem.
Conspicuous wet patches around the armpits or sweaty palms can leave sufferers acutely self-conscious in public settings and often unable to shake hands without undue embarrassment.
Sufferers complain of having to change their clothes up to three times a day, while others say they have become socially isolated due to the persistent need to avoid physical contact.
The condition can also be an occupational hazard for people needing to write or use a keyboard at work.
John O'Keeffe, a Dublin GP who specialises in the problem, says with all human functions, there is a wide range of what can be considered normal. "Some people sweat a lot, while others sweat hardly at all."
O'Keeffe says there is no hard and fast definition of hyperhidrosis as it is a subjective term, similar to tiredness, but "we tend to consider it as a level of sweating that is unacceptable to the person who has it".
He explains there are two types of hyperhidrosis. One is a generalised sweat occurring all over the body which usually stems from an underlying condition such as a tropical disease or an overactive thyroid.
The other, and more common form, is localised or primary hyperhidrosis. This typically affects areas such as the armpits, hands or feet where there is a higher concentration of sweat glands.
The condition is estimated to affect about 1 per cent of the population, although a recent US study suggested this was an underestimate, and that the figure may be closer to 3 per cent.
Primary hyperhidrosis affects both sexes equally and usually starts in late adolescence or in the sufferer's early 20s.
It does not impair the body's ability to function or regulate its temperature and is usually defined by doctors as idiopathic - arising from an unknown cause.
O'Keeffe says a common misconception is that heavy sweating causes or is associated with body odour.
"Sweat is almost completely odourless. Only when it comes in contact with bacteria on the skin does a smell occur. Most heavy sweaters, in any case, do not have a body odour problem," he says.
The condition is not necessarily prompted by hot temperatures, as sufferers are just as likely to sweat too much when it is cold as when it is hot.
"There is also no evidence that the condition is caused by stress but most sufferers do find the condition distressing," O'Keeffe says.
The most common areas affected are the armpits and the hands, but O'Keeffe says that it is rare that people have problems in both areas.
There are a range of treatments for excessive sweating and it appears to be a matter of finding one which suits the individual.
Most sufferers will be advised initially to try an antiperspirant, if they have not already done so.
Antiperspirants range from a simple talcum powder, which soaks up mild sweat, to stronger aluminium chloride-based products which aim to completely block the pores.
While antiperspirants are easy to use and represent a non-invasive treatment, for about 50 per cent of people they are a direct skin irritant, making their use, at least for an extended period, prohibitive.
There are others for whom antiperspirants simply don't work.
Another treatment often prescribed for heavy sweaters is Iontophoresis, where the hands or feet are submerged in water while an electrical current is conducted through the water. it is not clear why this helps but it is thought to temporarily block the pores.
Iontophoresis can cause skin irritation in the form of dryness or blistering, and many patients find the treatment cumbersome.
There are also several drug treatments including the use of beta blockers to reduce the effects of stress hormones such as adrenaline or noradrenaline.
Botox injections are now also used to treat excessive sweating. The protein can paralyse the sweat glands if injected into the gap between the nerve end and the gland.
But because of its toxic nature, the procedure requires a significant degree of precision and is favoured in areas like the armpit, as the gap between the muscle and the skin in the hand is so narrow that it is easy to inadvertently push the Botox into the muscle.
Although most experts acknowledge that Botox is an effective remedy for heavy sweating, it does have drawbacks as it only lasts up to six months and is expensive.
Most experts will advise hyperhidrosis sufferers to try more conservative measures before considering medical intervention.
However, when all else fails, some turn to surgery which is usually in the form of a sympathectomy - a procedure which removes certain portions of the sympathetic nervous system which service the water-producing eccrine sweat glands in the skin.
Denis Mehigan, consultant vascular Surgeon at St Vincent's Hospital, Dublin, says it appears that people with primary hyperhidrosis suffer from an overactivity of the nerves that supply the eccrine sweat glands.
Mehigan says: "As long as there is reasonable expectation of the outcome, a sympathectomy is a good procedure for certain patients."
The procedure is quite complex, as surgeons must go through the chest cavity to access the sympathetic nerves, which requires the lung to be partially collapsed.
"By dissecting the nerve tissue servicing the palms or the armpits, we can significantly reduce the sweating," he says.
Mehigan says that in about 40 per cent of patients there is a significant risk of compensatory sweating elsewhere in the body following the procedure but this is often preferable to the existing complaint.
"It may be less of a problem if you have sweating on your back than if you have it on your hands and it may not be anything as bad as it was originally.
"There are definite drawbacks but the majority are quite happy to accept them," he says.