Hyperhidrosis (excessive sweating) may be either focal or generalised, and either primary (no underlying cause) or secondary (underlying cause identified).¹ Common triggers include emotion and spicy foods.

• Primary focal hyperhidrosis may affect the axillae, palms, soles or scalp, and has no underlying cause. It usually starts in childhood or adolescence, but can occur at any age. Palmar and plantar hyperhidrosis may be present at birth.
• Secondary focal hyperhidrosis involves specific areas of the body, but is caused by an underlying condition.
• Generalised hyperhidrosis affects the entire body and is usually caused by medical conditions or drugs.¹

The prevalence of hyperhidrosis is unknown, mainly because many affected people are not seen for treatment.

Causes

Generalised hyperhidrosis¹

• Pregnancy.
• Anxiety.
• Drugs, e.g. anticholinesterases (pyridostigmine, neostigmine), antidepressants, pilocarpine eye drops, bethanechol, propranolol.
• Substance abuse or withdrawal (including alcohol).
• Heart failure, ischaemic heart disease, shock.
• Respiratory failure.
• Infections, including tuberculosis, brucellosis, HIV, abscess, and malaria.
• Malignancy, especially lymphoma.
• Thyrotoxicosis, hypoglycaemia, phaeochromocytoma, acromegaly, carcinoid tumour, hyperpituitarism, obesity, gout, menopause.
• Parkinson's disease, diencephalic epilepsy, hypothalamic lesions.
• Familial dysautonomia (Riley-Day syndrome).

Secondary focal hyperhidrosis

• Cerebrovascular disease, peripheral neuropathies, diabetic autonomic neuropathy, spinal cord lesions, and spinal tumours
• Intrathoracic neoplasms, e.g. mesothelioma.
• Gustatory sweating (sweating induced by food or drink), which may be due to diabetic neuropathy, preauricular herpes zoster, invasion of the cervical sympathetic trunk (by tumour or injury) or surgery to the parotid gland (e.g. Frey's auriculotemporal syndrome).
• Compensatory hyperhidrosis: injury to the sympathetic trunk (including after endoscopic thoracic sympathectomy)² or diabetic neuropathy may lead to an area of the body with absence of sweating, which then leads to an area of compensatory hyperhidrosis in another part of the body.
• Other causes include cervical rib, Raynaud's phenomenon, arteriovenous fistula, cold injury, rheumatoid arthritis, nail-patella syndrome

Presentation¹

• An underlying cause should be suspected if:
  • Generalised sweating.
  • Sweating during sleep (suggests tuberculosis, another infection, or Hodgkin's disease).
  • Symptoms and signs of systemic disease, e.g. fever, weight loss, anorexia, or palpitations.
  • The person is taking prescribed drugs that are known to cause sweating.
  • Unilateral or asymmetrical sweating (suggests a neurological lesion or tumour, an intrathoracic malignancy, or a cervical rib).
  • Symptoms and signs of any other causes of secondary focal hyperhidrosis or generalised hyperhidrosis.
• Assess whether anxiety may be an exacerbating factor.
• Diagnose primary focal hyperhidrosis when focal, visible, excessive sweating:
  • Occurs in at least one of the following sites: axillae, palms, soles, or craniofacial region, and
  • Has lasted at least 6 months, and
  • Has no apparent cause, and
  • Has at least two of the following characteristics:
    • Bilateral and relatively symmetrical.
    • Impairs daily activities.
    • Frequency of at least one episode per week.
    • Onset before 25 years of age.
    • Positive family history.
    • Cessation of local sweating during sleep.
  • If symptoms have lasted less than 6 months or onset is at 25 years of age or older, primary focal hyperhidrosis remains a likely diagnosis if other criteria are met, but extra care should be taken to exclude an underlying cause.

Investigations

If the presentation is characteristic of primary focal hyperhidrosis and there is no evidence of an underlying cause, no laboratory tests are required. Any initial investigations will often depend on individual context of patient and the history and examination but often include:

• Full blood count; blood film for malarial parasites may be indicated.
• ESR and/or CRP
• Renal function tests and electrolytes.
• Liver function tests.
• Fasting blood glucose.
• Thyroid function tests.
• Chest X-ray (may be useful to identify an intrathoracic neoplasm or a cervical rib).
• HIV testing.

Management

Generalised hyperhidrosis

Generalised hyperhidrosis is usually due to an underlying disorder and management is therefore directed at finding and treating any underlying cause (usually includes specialist referral).

Primary focal hyperhidrosis

• General advice:¹
  • Avoid clothes that show sweat marks readily (white or black are suitable colours). Wear loose-fitting clothing. Avoid man-made fibres, e.g. nylon.
  • Soap substitutes reduce skin irritation.
  • Avoid any obvious trigger factors.
  • Frequently change clothing, including shoes to allow them to dry properly, and avoid heavy occlusive footwear such as boots or sports shoes.
  • Primary axillary hyperhidrosis: use an antiperspirant rather than a deodorant, use armpit or sweat shields to absorb excess sweat and protect clothing.
  • Primary plantar hyperhidrosis: changing socks at least twice daily; use absorbent soles, and use absorbent foot powder twice daily; avoid occlusive footwear such as boots or sports shoes; wear leather shoes; alternate pairs of shoes on a daily basis to allow them to dry fully.
• 20% aluminium chloride hexahydrate in alcohol solution should be applied to dry skin of the axillae, feet, hands, or face (avoiding the eyes) at night just before sleep and washed off in the morning. The solution should be applied every 1-2 days until the condition improves and then as required. If successful, treatment can be continued indefinitely.¹
• Consider treating any underlying anxiety with cognitive behavioural therapy (drug treatment may worsen the hyperhidrosis).
• Refer to a dermatologist if the above measures are inadequate or unacceptable.
• Further treatments in secondary care:
  • Modified topical therapy: options include emollients, topical corticosteroids, different strengths of aluminium salts (up to 50%), and topical glutaraldehyde or formaldehyde.¹
  • Iontophoresis:
    • The sites of hyperhidrosis are immersed in warm water (or a wet contact pad may be applied) through which a weak electric current is passed.¹
    • Glycopyrronium bromide as a 0.05% solution is used in iontophoresis for more severe cases of hyperhidrosis affecting the plantar and palmar areas.
    • Some people seem to gain considerable symptom relief. Most report an improvement after 6-10 sessions. Maintenance treatment is usually required at 1-4-week intervals.¹
  • Botulinum type A toxin:
    • Botulinum A toxin-haemagglutinin complex is licensed for use intradermally for severe hyperhidrosis of the axillae unresponsive to topical antiperspirant or other antihidrotic treatment.
    • It is given by repeated intradermal injections into the affected area.
    • It has been shown to be safe and effective.³
  • Surgery:
    • Usually only considered if other treatment options have failed or have not been tolerated:
    • Resection of sweat glands using local anaesthesia:
      • Subcutaneous curettage is very effective and has fewer potential side-effects than sympathectomy.⁴
      • Complications of local axillary surgery include haematoma, scarring, and wound infections.
    • Sympathectomy (division of the sympathetic chain over the neck of the ribs under general anaesthesia):
      • Endoscopic thoracic sympathectomy: sympathectomy is usually carried out endoscopically via the transthoracic route.⁵
      • Mainly indicated as a last resort for severe palmar, axillary, and sometimes craniofacial hyperhidrosis. Lumbar sympathectomy is not used for plantar hyperhidrosis because of the risk of sexual dysfunction.¹
      • Compensatory hyperhidrosis is the most common adverse effect and causes sweating in such areas as the chest, back, thighs and groin, and can be extremely disabling.
      • Other complications include gustatory sweating, rhinitis, pneumothorax (usually resolves spontaneously), Horner's syndrome, brachial plexus injuries, postoperative neuralgia, and recurrent laryngeal nerve palsy.¹
• Other treatments include oral antimuscarinics, clonidine, diltiazem and benzodiazepines.¹

Complications

• Severe hyperhidrosis can cause extreme embarrassment that may lead to social and professional isolation.⁵
• Secondary infections.
• Dermatitis.

Prognosis

• Primary focal hyperhidrosis usually runs a chronic course, although a small number of people spontaneously improve after the age of about 25 years.¹

Document references

1. Hyperhidrosis, Clinical Knowledge Summaries (January 2009)
2. Sayeed RA, Nyamekye I, Ghauri AS, et al; Quality of life after transthoracic endoscopic sympathectomy for upper limb hyperhidrosis. Eur J Surg Suppl. 1998;(580):39-42. [abstract]
3. Naumann M, Jankovic J; Safety of botulinum toxin type A: a systematic review and meta-analysis. Curr Med Res Opin. 2004 Jul;20(7):981-90. [abstract]
4. Rompel R, Scholz S; Subcutaneous curettage vs. injection of botulinum toxin A for treatment of axillary hyperhidrosis. J Eur Acad Dermatol Venereol. 2001 May;15(3):207-11. [abstract]
5. Nyamekye IK; Current therapeutic options for treating primary hyperhidrosis. Eur J Vasc Endovasc Surg. 2004 Jun;27(6):571-6. [abstract]

Internet and further reading

• The Hyperhidrosis Support Group
• British Association of Dermatologists; Hyperhidrosis (information for patients)

Acknowledgements