Primary focal hyperhidrosis

Primary focal hyperhidrosis is one of two types of excessive sweating in which the sufferer experiences sweat loss from specific areas of their body. This differs from general hyperhidrosis in which the affected person sweats excessively from their entire body. Primary excessive sweating is often defined as ‘primary focal hyperhidrosis’ because the sufferer loses excess amounts of sweat from particular (‘focal’) parts of the body such as the hands and feet. But, this can be divided into the following sub-definitions:

• Primary focal hyperhidrosis
• Secondary focal hyperhidrosis

So what is the difference between the two? Primary focal hyperhidrosis occurs for no obvious reason and usually during childhood/puberty although it can develop at any time in life. Secondary focal hyperhidrosis is the same in that it also targets certain parts of the body, but, it is usually caused by an ongoing medical condition. The majority of cases of focal hyperhidrosis are usually primary whereas general hyperhidrosis is secondary.

Cause of primary focal hyperhidrosis

There is a genetic reason for this condition: it often occurs where someone has a close member of their family with this disease.

If you know of someone in your family that suffers from excessive sweating then this may explain why you have developed this condition. This is by no means automatic but it occurs in around two thirds of primary hyperhidrosis cases.

Primary focal hyperhidrosis is usually caused by a problem with the sympathetic nervous system.

The sympathetic nervous system

This is an involuntary part of your body’sautonomic nervous system which regulates a range of functions that are related to the ‘fight or flight’ response to stress. These include heart rate, digestion and the excretion of waste products from the body. But the function we are most interested in is sweat production.

How does this work?

The sympathetic nervous system detects changes in body temperature and reacts by transmitting signals through nerve channels (called ‘ganglia’) to sweat glands in the body. This triggers these glands to produce sweat which then cools the skin and lowers body temperature.

This prevents the body from overheating.

But these ganglia become over-active and produce excessive amounts of sweat. This particularly applies to the ‘thoracic sympathetic ganglion chain’ which is located alongside the spinal vertebrae within the chest cavity.

(Source: Hyperhidrosis UK)

This chain controls both the eccrine and apocrine sweat glands which are responsible for the production of sweat throughout the body.

The result is the condition we know as hyperhidrosis.

We have no control over the sympathetic nervous system.

Areas of the body affected by primary focal hyperhidrosis

This form of excessive sweating affects the following parts of the body:

• Armpits: known as ‘axillary hyperhidrosis’
• Hands: known as ‘palmar hyperhidrosis’
• Feet: known as ‘plantar hyperhidrosis’

The face can also be affected which also includes sweating from the scalp and neck. This becomes apparent in a social situation in which the sufferer experiences a prolonged increase in body temperature and a bright red facial appearance. This sometimes happens with palmar hyperhidrosis. Other possible areas of the body include the groin, chest and back although these are less commonly affected than the hands, feet and armpits.

Treatment for primary focal hyperhidrosis

There are several options available which include lifestyle changes, e.g. avoiding hot spicy foods, prescription deodorants, iontophoresis or surgery.

These are all recommended for this type of excessive sweating.

If you have secondary hyperhidrosis then your treatment will depend upon the underlying trigger of your excessive sweating.

Find out more in our treatment for excessive sweating section.