Hyperhidrosis

ByShinjita Das, MD MPH, Massachusetts General Hospital
Reviewed/Revised Mar 2024
View Patient Education

(See also Introduction to Sweating Disorders.)

Etiology of Hyperhidrosis

Hyperhidrosis can be focal or generalized.

Focal sweating

Emotional causes are common, causing sweating on the palms, soles, axillae, and forehead at times of anxiety, excitement, anger, or fear. It may be due to a generalized, stress-increased sympathetic outflow. Sweating is also common during exercise and in hot environments. Although such sweating is a normal response, patients with hyperhidrosis sweat excessively and under conditions that do not cause sweating in most people.

Gustatory sweating (sweating in response to or in anticipation of eating) can result from a number of causes; however, most often the cause is unknown. For example, sweating around the lips and mouth can occur when ingesting foods and beverages that are spicy or hot in temperature.

Pathologic causes include diabetic neuropathy, facial herpes zoster, cervical sympathetic ganglion invasion, central nervous system injury or disease, or parotid gland injury.

Frey syndrome is a neurologic condition due to injury to or around the parotid glands resulting from surgery, infection, or trauma. Frey syndrome disrupts the auriculotemporal nerve, with subsequent inappropriate regeneration of parotid parasympathetic fibers into sympathetic fibers innervating local sweat glands in skin where the injury took place (1). As a result, the misplaced parasympathetic fibers (which normally cause salivation as a gustatory response) now instead trigger sympathetic fibers that cause (inappropriate) redness and sweating of the preauricular cheek.

Other causes of focal sweating include pretibial myxedema (shins), hypertrophic osteoarthropathy (palms), blue rubber bleb nevus syndrome, and glomus tumor (over lesions).

Compensatory sweating is intense sweating after sympathectomy.

Generalized sweating

Generalized sweating involves most of the body. Although most cases are idiopathic, numerous conditions can be involved (see table Some Causes of Generalized Sweating).

Table

Etiology reference

  1. 1. Motz KM, Kim YJ. Auriculotemporal Syndrome (Frey Syndrome). Otolaryngol Clin North Am. 2016;49(2):501-509. doi:10.1016/j.otc.2015.10.010

Symptoms and Signs of Hyperhidrosis

Sweating is often present during examination and sometimes is extreme. Clothing can be soaked, and palms or soles may become macerated and fissured.

Palmar or plantar skin may appear pale.

Hyperhidrosis can cause emotional distress to patients and may lead to social withdrawal.

Diagnosis of Hyperhidrosis

  • History and examination

  • Iodine and starch test

  • Tests to identify a cause

Hyperhidrosis can be primary or secondary to an underlying medical condition. It is diagnosed by history and examination but can be confirmed with the iodine and starch test (1). For this test, iodine solution is applied to the affected area and allowed to dry. Cornstarch is then dusted on the area, which makes areas of sweating appear dark. Testing is necessary only to confirm foci of sweating (as in Frey syndrome, or to locate the area needing surgical or botulinum toxin treatment) or in a semiquantitative way when following the course of treatment. Asymmetry in the pattern of sweating suggests a neurologic cause.

Laboratory tests to identify a cause of hyperhidrosis are guided by the patient's other symptoms and might include, for example, complete blood count to detect leukemia, serum glucose to detect diabetes, and thyroid-stimulating hormone to screen for thyroid dysfunction.

Diagnosis reference

  1. International Hyperhidrosis Society: Diagnosis guidelines: Primary hyperhidrosis. Accessed March 29, 2024.

Treatment of Hyperhidrosis

  • Aluminum chloride hexahydrate solution

  • Topical anticholinergic medications

  • Oral anticholinergic medications

  • Oral clonidine

  • Botulinum toxin type A

  • Medical devices

  • Surgery

Initial treatment of focal and generalized sweating is similar. Various methods may be effective (1). Topical agents such as aluminum chloride hexahydrate solution and topical anticholinergic medications are usually considered first-line therapy because they are noninvasive and have few adverse effects.

(See also clinical guidelines from the International Hyperhidrosis Society.)

Aluminum chloride hexahydrate solution

Initially, several applications weekly are needed to achieve control, then a maintenance schedule of once or twice a week is followed. If treatment under occlusion is irritating, it should be tried without occlusion. This solution should not be applied to inflamed, broken, wet, or recently shaved skin.

High-concentration, water-based aluminum chloride solutions may provide adequate relief in milder cases.

Topical anticholinergic medications

2). Caution should be used in patients who are sensitive to the effects of anticholinergic medications.

Oral anticholinergic medications

3) can be used to decrease sweating but can be limited by anticholinergic adverse effects, including dry mouth, dry skin, flushing, blurred vision, urinary retention, mydriasis, and cardiac arrhythmias.

Clonidine

Botulinum toxin type A

Botulinum toxin type A is a neurotoxin that decreases the release of acetylcholine from sympathetic nerves serving eccrine glands.

Injected directly into the axillae, palms, or forehead, botulinum toxin inhibits sweating for about 5 months depending on dose. The efficacy of botulinum toxin type A for hyperhidrosis is supported by data from randomized trials (4, 5). Of note, in the United States botulinum toxin is approved only for axillary hyperhidrosis and may not be covered by insurance for other sites of hyperhidrosis.

Complications include local muscle weakness and headache. Injections are effective but painful and expensive, and treatment must be repeated 2 to 3 times per year.

Another consideration is botulinum toxin type A liposomal cream (6).

Medical devices

Tap-water iontophoresis, in which salt ions are introduced into the skin using electric current, is an option for patients unresponsive to topical treatments; however, supporting data are limited.

Although the treatments are usually effective, the technique is time-consuming and somewhat cumbersome, and some patients tire of the routine.

A microwave-based device can heat and subsequently permanently destroy sweat glands, resulting in efficacy over at least several months (7). Patients may benefit from 2 treatments at least 3 months apart.

Laser devices have been used to manage hyperhidrosis. These include diode laser, neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, and fractionated microneedle radiofrequency devices (1). Laser-assisted delivery of botulinum toxin A solution with a fractionated CO2 laser can also be considered.

Surgery

Surgery is indicated if more conservative treatments fail.

Patients with axillary sweating can be treated with surgical excision of axillary sweat glands through open dissection or by liposuction (8); the latter appears to have lower morbidity.

Patients with palmar sweating can be treated with endoscopic transthoracic sympathectomy (9). The potential morbidity of surgery must be considered, especially in sympathectomy. Potential complications of sympathectomy include phantom sweating (a sensation of sweating in the absence of sweating), compensatory hyperhidrosis (increased sweating in untreated parts of the body), gustatory sweating, neuralgia, and Horner syndrome. Compensatory hyperhidrosis is most common after endoscopic transthoracic sympathectomy, developing in up to 80% of patients (10), and can be disabling and far worse than the original problem.

Treatment references

  1. 1. Henning MAS, Bouazzi D, Jemec GBE: Treatment of Hyperhidrosis: An Update. Am J Clin Dermatol 23(5):635-646, 2022. doi: 10.1007/s40257-022-00707-x

  2. 2. Glaser DA, Hebert AA, Nast A, et al: Topical glycopyrronium tosylate for the treatment of primary axillary hyperhidrosis: Results from the ATMOS-1 and ATMOS-2 phase 3 randomized controlled trials. J Am Acad Dermatol pii:S0190-9622(18)32224-2, 2018. doi: 10.1016/j.jaad.2018.07.002

  3. 3. Wolosker N, de Campos JR, Kauffman P, Puech-Leao P. A randomized placebo-controlled trial of oxybutynin for the initial treatment of palmar and axillary hyperhidrosis. J Vasc Surg. 2012;55(6):1696-1700. doi:10.1016/j.jvs.2011.12.039

  4. 4. Heckmann M, Ceballos-Baumann AO, Plewig G; Hyperhidrosis Study Group. Botulinum toxin A for axillary hyperhidrosis (excessive sweating). N Engl J Med. 2001;344(7):488-493. doi:10.1056/NEJM200102153440704

  5. 5. Naumann M, Lowe NJ. Botulinum toxin type A in treatment of bilateral primary axillary hyperhidrosis: randomised, parallel group, double blind, placebo controlled trial. BMJ. 2001;323(7313):596-599. doi:10.1136/bmj.323.7313.596

  6. 6. Lueangarun S, Sermsilp C, Tempark T. Topical Botulinum Toxin Type A Liposomal Cream for Primary Axillary Hyperhidrosis: A Double-Blind, Randomized, Split-Site, Vehicle-Controlled Study. Dermatol Surg. 2018;44(8):1094-1101. doi:10.1097/DSS.0000000000001532

  7. 7. Glaser DA, Coleman WP 3rd, Fan LK, et al. A randomized, blinded clinical evaluation of a novel microwave device for treating axillary hyperhidrosis: the dermatologic reduction in underarm perspiration study. Dermatol Surg. 2012;38(2):185-191. doi:10.1111/j.1524-4725.2011.02250.x

  8. 8. Cerfolio RJ, De Campos JR, Bryant AS, et al. The Society of Thoracic Surgeons expert consensus for the surgical treatment of hyperhidrosis. Ann Thorac Surg. 2011;91(5):1642-1648. doi:10.1016/j.athoracsur.2011.01.105

  9. 9. Drott C, Göthberg G, Claes G. Endoscopic transthoracic sympathectomy: an efficient and safe method for the treatment of hyperhidrosis. J Am Acad Dermatol. 1995;33(1):78-81. doi:10.1016/0190-9622(95)90015-2

  10. 10. Gossot D, Galetta D, Pascal A, et al. Long-term results of endoscopic thoracic sympathectomy for upper limb hyperhidrosis. Ann Thorac Surg. 2003;75(4):1075-1079. doi:10.1016/s0003-4975(02)04657-x

Key Points

  • Hyperhidrosis can be focal or generalized.

  • Asymmetric hyperhidrosis suggests a neurologic cause.

  • Although generalized sweating is usually normal, consider cancer, infection, and endocrine disorders as directed by patient symptoms.

  • Obtain laboratory tests to determine systemic causes based on clinical findings.

  • Consider surgical options in patients who do not respond to medications or device therapy; surgical options include excision of axillary sweat glands and endoscopic transthoracic sympathectomy for palmar sweating, which carries risk of significant adverse effects.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  1. International Hyperhidrosis Society: Clinical guidelines for the treatment of hyperhidrosis

Drugs Mentioned In This Article
quizzes_lightbulb_red
Test your KnowledgeTake a Quiz!
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID