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Hyperhidrosis Diagnosis


When considering a diagnosis of hyperhidrosis, the doctor will want to establish whether an underlying medical condition is causing the symptoms – i.e. whether it is primary or secondary hyperhidrosis.

This will most like be achieved through a combination of blood and urine tests and a clinical history.

The clinical history is particularly useful since the pattern of symptoms is a useful discriminatory feature; for instance night sweating is unusual in primary hyperhidrosis; and whether there is focal sweating (affecting part of the body) which more often relates to primary hyperhidrosis or generalised sweating all over, which tends to be related to an underlying problem.

Where test results point to secondary hyperhidrosis, specific test will follow to confirm the underlying cause and a treatment plan for this condition established.

Primary hyperhidrosis is usually diagnosed if:

  • No underlying cause has been found,
  • There is at least one episode of excessive sweating a week,
  • Only parts of the body, rather than the whole body, are affected,
  • Both of the affected body parts (such as both armpits or both hands) are excessively sweaty, and
  • There are no night sweats.

That said, more specific test are also available to assess the severity of the condition.

Assessment methods

Where there is Axillary involvement (sweating of the armpits), one of the simplest tests is, an assessment of the sweat stains of shirts and blouses. A sweat stain with a diameter less than 5 cm is generally considered normal. Mild hyperhidrosis can be associated where stains of 5 to 10 cm diameter are found, but still confined to the armpit. Stains of 10 to 20 cm are seen in moderate hyperhidrosis, while stains over 20 cm reaching the waistline are common in severe hyperhidrosis.

For palmar hyperhidrosis, (the hands) a low grade of involvement would be a moist palmar surface without visible droplets of perspiration. If palmar sweating extends toward the fingertips, the condition can be considered moderate, and if sweat drips off the palm and reaches all the fingertips, it would be classed severe.

Another common test is the Minor Tests, or starch/Iodine sweat test, which assesses the area involved in excessive sweating.

The test is of little value in quantifying the degree of hyperhidrosis, as there is poor correlation between the area of sweating and the sweat rate.

In this sweat test, a 2% iodine solution is applied to the area of interest (usually the axilla) and allowed to dry. Starch in powder form (corn starch) is then brushed on the area. In areas of sweat, the light brown iodine colour turns dark purple as an iodine-starch complex forms in the liquid medium. The worse affected area can be visualised and marked, and photography of the involved area allows for documentation and follow-up comparison after treatment.

Quantitative methods

A quantitative approach to assessing severity is gravimetric measurement, which can be done on the palm and in the axilla. This technique is often utilised in clinical trials but is not part of routine clinical practice.

After drying the surface, a pre-weighed piece of absorbent paper is applied to the palm or axilla for a set period of time. The paper is then weighed and the rate of sweat production is calculated in mg/min.

Another quantitative test is “Evaporimetry”, in which a device measures the rate of skin water vapour loss. Again, this test is used more in clinical trials than in diagnostic practice.


Continue here to read about Treatment Options for Hyperhidrosis.