Hyperhidrosis

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

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

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

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.

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

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).

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 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.