Sweating disorders: hyperhidrosis and hypohidrosis

1 February 2013, by MAILLARD H. & BARA C.



Hyperhidrosis is excessive secretion of sweat. It has a not inconsiderable impact on the quality of life of sufferers because it interferes with daily activities and it leads to psychological and social repercussions. Hyperhidrosis can be a primary condition or it can be secondary to an internal disease or a neurological disorder.


Generalised hyperhidrosis is often organic, while localised hyperhidrosis is in most cases a primary condition and regional hyperhidrosis often has a neurological cause.

Generalised hyperhidrosis

Idiopathic generalised hyperhidrosis is rare and it is diagnosed by exclusion. Everyday circumstances like pregnancy and the menopause are very common causes, but there are also many others: chronic alcohol misuse, vasovagal episodes, hyperthyroidism, diabetes, acromegaly, pheochromocytoma, and carcinoid tumours.

A lymphoma, an occult cancer, and tuberculosis are the classic causes to look for in a patient with excessive sweating that increases at night. Hyperhidrosis accompanies many kinds of infections.

Neurological diseases such as Parkinson’s disease and multiple sclerosis, and cerebrovascular accidents can all be accompanied by hyperhidrosis, as can other illnesses.

Medicines are often implicated (amiodarone, opiates, pentoxyfylline, interferon, fluoxetine). There are other medicines that are less commonly involved but that are also worth mentioning: some NSAIDs like naproxen, beta-blockers and anti-oestrogens.

Primary localised hyperhidrosis

Axillary hyperhidrosis is the most common kind, followed by palmar, plantar, inguinal and craniofacial hyperhidrosis. It is most likely to have a genetic cause. It can be defined as excessive sweating for more than six months with no apparent cause and at least two of these criteria:

– Bilateral and relatively symmetrical sweating

– Occurs at least once a week

– Age of onset under 25 years

– Sweating stops at night

– Family history

Secondary localised hyperhidrosis

In general this form of hyperhidrosis is asymmetrical and always pathological, of neurological origin, and it presents with a suggestive pattern of affected sites.

Frey’s syndrome is sweating of one side of the face, sometimes associated with erythema and oedema, that is often triggered by chewing or ingesting certain foods. It can be congenital or develop after surgery or a trauma to the parotid region.

Hyperhidrosis can occur with cerebrovascular accidents and the excessive sweating is localised to the paralysed side.

Localised hyperhidrosis often develops after amputation of a limb and it can exacerbate local problems with the stump, which can cause delays in the patient’s ability to readjust.


Hyperhidrosis is still under-treated as it is not considered to be a disease. At present we do have effective treatments, ranging from topical treatments to surgery.

Medical treatments

Topical antiperspirants

The factor that differentiates antiperspirants from deodorants, the purpose of which is to mask the odours that accompany perspiration, is that they have an effect on sweat excretion. The ingredient at the forefront is aluminium salts (aluminium chloride and chlorohydrate), which have been demonstrated their efficacy in a number of clinical studies. Aluminium chloride is the most effective topical antiperspirant. In order to minimise irritation, aluminium chloride must be applied to dry armpits at bedtime, and then completely washed off 6 to 8 hours later. It is therefore applied every 24-48 hours until sweating levels normalise, then once every 1 to 3 weeks.

The impact on health of exposure to aluminium has been the source of numerous controversies and since the 1990s the use of topical products containing aluminium salts has been suspected to be one cause of breast cancers. According to AFSSAPS (the French healthcare products safety agency) and a few studies, there is no link between the use of cosmetic products containing aluminium salts and breast cancer.


This method consists of exposing the hands and/or feet to a continuous electrical current transmitted by immersion in water. The patient places his/her hands and/or feet in the baths. Water is poured in and the patient is able to gradually increase the intensity of the current using a control in the bath until he/she feels a tingling sensation. After about ten minutes, the current is turned down to zero. Three sessions are required during the first week, then two in the second week, followed by three over the following two weeks. The results are generally visible by around the fourth session. After this a maintenance session needs to be scheduled after two to three weeks, and then every one to two months.

This treatment is formally contraindicated for anyone with a pacemaker. To be on the safe side, this treatment should be avoided by pregnant women and patients with an orthopaedic implant, depending on its size and on the trajectory of the current. Wounds or fissures could be a source of pain, so either the strength of the current may have to be lowered, the wound may need to be protected by a greasy substance or hydrocolloid dressing, or indeed the treatment may need to be paused for a time.


Oxybutynin (Ditropan®) has been shown to be useful in a number of cases. In our experience, this medicine leads to a clear improvement in almost 80% of cases. Nonetheless, it is possible for treatment become less effective after a time. The contraindications are prostate adenoma, closed angle glaucoma, tachycardia, and myasthenia gravis. The side effects are inescapable and dose-dependent: dry mouth, blurred vision, constipation, tachycardia and feeling faint. It is useful to start with small doses and then make stepwise increases up to a maximum dose of half a tablet 3 times a day, and it is important to stop at the minimum effective dose.

Propranolol and diltiazem have sometimes been used. The ratio between benefits and side effects does not seem to be at all favourable. Some anti-serotonin antidepressants can have an effect on hyperhidrosis (e.g.: Deroxat®).

Botulinum toxin injections

Treatment with botulinum toxin has shown a very valuable efficacy in hyperhidrosis and has improved quality of life.

The injection technique is fairly typical. The areas that are prone to hyperhidrosis are mapped out by applying an alcoholic iodine solution followed by maize starch to areas of perspiration production, which produces a black stain.

The side effects for treatment to the armpits are pain during the injections, although this is generally mild and can be relieved by prior application of Emla® cream. With injections to the palms, pain is the key problem to anticipate. Applying Emla® cream does not have much effect; use of Kalinox® gas (nitrous oxide and oxygen) can produce an acceptable level of analgesia. Techniques using hypnosis can also be very useful and lead to analgesia of the hands or feet; however this does require prior training. The other side effect worth noting is moderate and transient (generally lasting less than a month) weakness of the intrinsic muscles of the hand, which affects around 5% of patients.

The length of time for which botulinum toxin injections remain effective varies, ranging from 4 to 25 months and it appears that this duration increases the more injections the patient has. Botulinum toxin is for hospital prescription only and cannot be released to patients. For this reason, the legislation stipulates that the injections must be administered in a day hospital setting.

Surgical treatment: thoracic sympathectomy

Sectioning the sympathetic nerve in the chest (sympathectomy) leads to a complete end to sweating in the upper part of the body. After the operation sweating can only occur in the lower part of the body. This is called compensatory hyperhidrosis and it is the main problem with surgery.

The complications are either uncommon and relatively harmless or extremely rare and serious. Post-operative pain can sometimes be worrying but it is always transient. The very rare complications include involvement of the vascular and nervous system and heart rhythm disorders.

The side effects of surgical sympathectomy are at the heart of the issues surrounding the indication for surgery. This is because it is the intensity of compensatory hyperhidrosis affecting the lower part of the body that will influence the patient’s quality of life post-operatively. This effect is a consistent physiological response and it must not be presented as a complication. It affects between 14 - 90 % of patients depending on the study


Assess the significance of the hyperhidrosis

After confirming that the hyperhidrosis is primary, it is appropriate to assess the significance of the problem before offering treatment:

– The scale of severity commonly used is the HDSS:

• Level 1: My sweating is never noticeable and never interferes with my daily activities.

• Level 2: My sweating is tolerable but sometimes interferes with my daily activities.


• Level 3: My sweating is barely tolerable and frequently interferes with my daily activities.

• Level 4: My sweating is intolerable and always interferes with my daily activities.


Axillary hyperhidrosis (Figure 7)

Palmar hyperhidrosis (Figure 8)

Axillary + palmar + plantar hyperhidrosis (Figure 9)


Excessive sweating



Hypohidrosis is a fall in the excretion of sweat. When it is absent altogether the term used is anhidrosis.


Sweat is an important factor in skin hydration; the result of hypohidrosis or anhidrosis is severely dry skin. The patient is unable to tolerate heat or physical exertion, which may be followed by a fever that can sometimes be dangerous or by a feeling of being generally unwell.

Additional examinations are rarely used in practice, and are only seen in clinical studies.


A fall in sweating is linked to a low number or even an absence of sweat glands in the skin or to dysfunctional sweat excretion. This dysfunction may be due to a neurological problem or to a malformation of the gland that leaves it ineffective.

Congenital generalised or localised hypohidrosis would most often occur within a disease of multiple abnormalities in which hypohidrosis is associated with changes to the nails, teeth, skin or other organs.

Acquired hypohidrosis can be generalised or localised. Cases are linked to neurological disease (leprosy, multiple sclerosis, diabetes, hypothyroidism), tumours (lymphoma) or are associated with chronic skin diseases (urticaria, psoriasis, erythrodermas, radiodermatitis).


– Protection from heat: heat intolerance is the main sign of hypo- or anhidrosis and it entails consequences that are challenging for the patient. They have to maintain a cool environment, use air conditioning in summer, use water sprays, and wear light clothing, preferably made from natural materials.

– Avoid physical exertion.

– Avoid and treat fever.

– Maintain hydrated skin.


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