Therapeutic Update on Hyperhidrosis

Hyperhidrosis is defined as non-physiological, excessive sweating that is not caused by physical activity, which occurs in a localized, symmetrical distribution. It affects from 2.8% - 5% of the population and can negatively impact one’s quality of life due to embarrassment and shying away from social interactions. The most frequently affected areas are the axillae, palms, soles, face, and groin. While the precise eitology of focal hyperhyidrosis is unknown, it is thought that sympathetic overstimulation of normal eccrine glands is the mostly likely cause. The onset usually occurs during childhood or adolescence; 30%-50% of patients have a positive family history. During sleep, hyperhidrotic individuals sweat normally. Interestingly, patients with axillary hyperhidrosis usually do not have bromhidrosis (pungent sweat odor).¹ Due to recent drug development and breakthough technology, there are now several treatment options available. Choice of therapy may depend on the severity of sweating and the locations involved.

Topical solutions are the most commonly used first-line, least costly option. Aluminum chloride solutions in 10% - 15% concentrations are used to reduce axillary sweating or palmoplantar hyperhidrosos. The aluminum temporarily occludes the sweat glands. Localized primary irritant contact dermatitis can occur, which can limit its use. Recently, a new topical formulation containing 15% aluminum chloride and 2% salicylic acid showed that 75% of 30 patients were somewhat or very satisfied after treatment. Mean HDSS (hyperhidrosis disease severity scale)^*2 scores decreased from a baseline of 3.3 to 2.12 by 3 months.³ The non-alcohol gel vehicle was less irritating than an alcohol base.⁴

BTX-A injections can be delivered subdermally in the axillae, palms, or soles. Repeated injections are necessary every 6 to 12 months. BTX-A works by blocking the release of acetylcholine, a neurotransmitter secreted by sympathetic nerves innervating the sweat glands. Highly effective in achieving greater than a 90% reduction in sweating in more than 90% of patients, maintenance costs are relatively high. Typical starting doses are 50 units of BTX-A per axilla or 100 units of BTX-A per palm. The main contraindications to botulinum toxin therapy include neuromuscular disorders such as myasthenia gravis, pregnancy and lactation.⁵

Oral medication, such as glycopyrrolate and propantheline bromide can diminish sweating; however, due to systemic anticholinergic side effects such as dry mouth, blurred vision, constipation, and urinary obstruction, systemic anticholinergics are often not well tolerated. Other agents such as clonazepam, diltiazem, clonidine, and paroxetine have also been useful in isolated cases.^6,7

A series of sessions delivering micro amounts of electric current through tap water can diminish palmoplantar sweating. While the mechanism of action remains unknown, it may result from plugging the eccrine sweat gland pores or by a complex mechanism involving changes in reabsorption of sodium. Low-cost maintenance therapy is needed for sustained efficacy.⁸

Direct excision of sweat glands under visualization has been performed in the axillae.⁹ Also, liposuction with tumescent anesthesia using a blunt or specialized cannula to rasp the undersurface of the dermis has been done. These surgical methods are often associated with swelling and bruising, and require healing time.^10,11,12 Patients with severe sweating who have been recalcitrant to conventional therapy can undergo an endoscopic transthoracic sympathectomy. While surgical ablation of the sympathetic nerve chain supplying the sweat glands in the axillae or hands can be effective with long-term results, the risk of injury to the lungs and other nerve structures in the chest is significant. Often, the bothersome side effect of compensatory hyperhidrosis of the lower portion of the body occurs post-operatively.¹³

In one pilot study of six patients, a long-pulsed Nd:YAG (Candela) at hair reduction settings yielded improvements in subjective and objective measures of axillary sweating up to 9 months; however, there were no changes in the histology of axillary skin.¹⁴ In another study, a long-pulsed 800 nm. diode laser (Light Sheer/Lumenis) used to deliver 5 cycles of laser treatment at monthly intervals to 21 patients on 1 axilla only (with the contralateral side serving as the control) failed to show significant sweat reduction compared to the untreated side.¹⁵ Most recently, 15 subjects with axillary hyperhidrosis were treated