Hyperhidrosis is excessive sweating, which can be focal or diffuse and has multiple causes. Sweating of the axillae, palms, and soles is most often a normal response due to stress, exercise, or environmental heat; diffuse sweating is usually idiopathic but, in patients with compatible findings, should raise suspicion for cancer, infection, or endocrine disease. Diagnosis is usually clinically evident; however, tests for underlying causes may be indicated in some cases. Treatments include topical aluminum chloride, topical or oral anticholinergic medications, tap-water iontophoresis, oral clonidine, botulinum toxin, a microwave-based or laser device, and, in extreme cases, surgery.
(See also Introduction to Sweating Disorders.)
Etiology of Hyperhidrosis
Hyperhidrosis can be focal or generalized. Hyperhidrosis can be primary or secondary to an underlying medical condition.
Focal sweating
Emotional causes (eg, anxiety, excitement, anger, fear) commonly cause sweating on the palms, soles, axillae, and forehead. Such sweating 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, including 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 parotid gland injury, diabetic neuropathy, facial herpes zoster, cervical sympathetic ganglion invasion, or central nervous system injury or disease.
Frey syndrome (auriculotemporal syndrome) is a neurologic condition caused by 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 a type of hyperhidrosis caused by 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
Type | Examples |
|---|---|
Cancer* | Lymphoma, leukemia (particularly causing night sweats), adrenal tumors |
Central nervous system | Trauma†, autonomic neuropathy |
Medications and other substances | Antidepressants, aspirin, nonsteroidal anti-inflammatory drugs, hypoglycemic agents, caffeine, theophylline, opioid withdrawal |
Endocrine disorders | Hyperthyroidism, hypoglycemia, excessive secretion of sex hormones caused by gonadotropin-releasing hormone (GnRH) agonists |
Idiopathic | — |
Infections* | Tuberculosis, endocarditis, systemic fungal infections |
Other | Carcinoid syndrome, pregnancy, menopause, anxiety, fever |
* Primarily nocturnal generalized sweating (night sweats). † Frey syndrome is a disorder that results from aberrant regeneration of parasympathetic nerve fibers after damage to the auriculotemporal nerve, most commonly from carotid surgery. Misdirected parasympathetic fibers re-innervate cutaneous sweat glands and blood vessels instead of the parotid gland, causing sweating, flushing, and warmth in the preauricular region during eating. | |
Etiology reference
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 physical examination
Iodine and starch test
Tests to identify a cause
The diagnosis of hyperhidrosis is primarily by history and physical examination but can be confirmed with the iodine and starch test (Minor 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.
The Walling criteria can be used to help differentiate primary from secondary hyperhidrosis with positive predictive value of 99% and negative predictive value of 85% (2).
These criteria for primary hyperhidrosis include 6 or more months of excessive sweating along with at least 4 of any of the following:
Sweating that primarily affects eccrine-predominant sites (eg, axillae, palms, soles, craniofacial areas)
Bilateral and symmetric distribution
Absence of nocturnal sweating
Episodes occurring at least weekly
Age of onset ≤ 25 years
Family history of hyperhidrosis
Impairment of daily activities
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 mellitus, and thyroid-stimulating hormone to screen for thyroid dysfunction.
Diagnosis references
1. International Hyperhidrosis Society. Diagnosis guidelines: Assessment Methods for Primary Hyperhidrosis. Accessed April 23, 2026.
2. Walling HW. Clinical differentiation of primary from secondary hyperhidrosis. J Am Acad Dermatol. 2011;64(4):690-695. doi:10.1016/j.jaad.2010.03.013
Treatment of Hyperhidrosis
Topical strategies (eg, aluminum chloride hexahydrate solution, topical anticholinergics)
Botulinum toxin type A or iontophoresis
Oral agents (eg, anticholinergics, clonidine)
Medical devices (eg, energy based)
Surgery
Initial treatment of focal and generalized sweating is similar. Various methods may be effective (1, 2).
The management ladder typically includes a step-wise approach, beginning with less invasive therapies (eg, topical aluminum chloride, topical anticholinergics), progressing to procedural treatments (eg, botulinum toxin type A injections or iontophoresis), and, if needed, advancing to oral agents and more advanced interventions, including energy-based devices and surgical procedures.
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.
Aluminum chloride hexahydrate solution
Aluminum chloride hexahydrate (an antiperspirant) 6 to 20% solution in absolute ethyl alcohol is indicated for the topical treatment of axillary, palmar, and plantar sweating. Lower concentrations are available over-the-counter. Higher concentrations (eg, 20%) require a prescription. The solution precipitates salts, which block sweat ducts.
It is most effective when applied nightly and should be washed off in the morning. Sometimes an oral anticholinergic can be taken before application to prevent sweat from washing the aluminum chloride away.
Initially, several applications weekly are needed to achieve control, then a maintenance schedule of once or twice a week is followed. Treatments may be applied under occlusion; however, if this 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
Glycopyrronium tosylate 2.4% cloth wipes are used to treat primary axillary hyperhidrosis in patients 9 years of age and older (3). Caution should be exercised in patients who are sensitive to the effects of anticholinergic medications.
Other topical anticholinergic options include glycopyrronium bromide, sofpironium bromide, and oxybutynin.
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 approximately 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 licensed for use only for the treatment of axillary hyperhidrosis; however, it has been used off-label for other sites of hyperhidrosis.
Complications include local muscle weakness and headache. Injections are effective but use may be limited by adverse effects (eg, injection site pain) and logistical considerations (eg, high cost of off-label treatment, need for repeated injections 2 to 3 times per year).
Another consideration is botulinum toxin type A liposomal cream (6).
Oral anticholinergic medications
Glycopyrrolate or oxybutynin (7) 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. Caution should be exercised when considering long-term use of oral anticholinergics. Chronic oxybutynin may cause cognitive impairment and increase the risk of dementia, especially in older adults (8). Anticholinergics should also be used cautiously in patients with comorbidities that can be exacerbated by anticholinergic effects (eg, glaucoma, paralytic ileus, severe ulcerative colitis, toxic megacolon, myasthenia gravis,Sjögren syndrome).
Clonidine
Oral clonidine is an alpha-2-adrenergic agonist that decreases sweating mediated by sympathetic nervous system activity.
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.
Iontophoresis is a treatment for excess sweating of the feet.
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The affected areas (typically palms or soles) are placed in tap-water basins that each contain an electrode across which a 15- to 25-mA current is applied for 10 to 20 minutes. This routine is performed daily for 1 week and then repeated weekly or bimonthly. Iontophoresis may be made more effective by dissolving anticholinergic tablets (eg, glycopyrrolate) into the basin water.
Although the treatments are usually effective, the technique is time-consuming and somewhat cumbersome, and some patients may find the routine tiresome.
A microwave-based device can heat and subsequently permanently destroy sweat glands, resulting in efficacy over at least several months (9). Some longitudinal data suggest sustained efficacy beyond 6 months with very high success rates (10).
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 (11); the latter appears to have lower morbidity.
Patients with palmar sweating can be treated with endoscopic transthoracic sympathectomy (12). 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 (13), and can be disabling and more severe that the initial presentation (ie, presurgery).
Treatment references
1. Henning MAS, Bouazzi D, Jemec GBE. Treatment of Hyperhidrosis: An Update. Am J Clin Dermatol. 2022;23(5):635-646. doi: 10.1007/s40257-022-00707-x
2. International Hyperhidrosis Society. Clinical Guidelines. Accessed April 23, 2026.
3. 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. 2019;80(1):128-138.e2. doi:10.1016/j.jaad.2018.07.002
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. 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. 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. 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
8. Chancellor MB, Lucioni A, Staskin D. Oxybutynin-associated Cognitive Impairment: Evidence and Implications for Overactive Bladder Treatment. Urology. 2024;186:123-129. doi:10.1016/j.urology.2023.11.033
9. 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
10. Wimmer F, Ramic A, Nolte JP, et al. Evaluation of Efficacy and Safety of miraDry® Procedure in the Treatment of Primary Axillary Hyperhidrosis. Aesthetic Plast Surg. 2025;49(9):2545-2551. doi:10.1007/s00266-024-04558-1
11. 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
12. 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
13. 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 and of primary or secondary origin.
Asymmetric hyperhidrosis suggests a neurologic cause.
Although generalized sweating can be normal, cancer, infection, and endocrine disorders should be considered, directed by patient symptoms.
Laboratory tests to determine systemic causes should be obtained based on clinical findings.
Treatment is with topical agents (eg, aluminum chloride solutions), botulinum toxin, oral anticholinergic medications, oral clonidine, or via the use of a medical device (eg, tap-water iontophoresis, microwave-based, laser device).
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.
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