The Place of Botulinum Toxin Type A in the Treatment of Focal Hyperhidrosis

N. Lowe; A. Campanati; I. Bodokh; S. Cliff; P. Jaen; O. Kreyden; M. Naumann; A. Offidani; J. Vadoud; H. Hamm

Disclosures

The British Journal of Dermatology. 2004;151(6) 

In This Article

Palmar Hyperhidrosis

Topical Treatments. The main topical treatments for palmar hyperhidrosis are aluminium salts, glutaraldehyde, formaldehyde and tannic acid (strong tea), which have been shown to have beneficial effects, although they are effective only in mild hyperhidrosis. In addition, brown staining of the skin, and in the case of formaldehyde, its sensitizing potential, are limiting side-effects (Evidence level: IIb).[3]

Oral Treatments. The oral agents discussed under axillary hyperhidrosis are also applicable for patients presenting with palmar hyperhidrosis.

Sympathectomy. Traditionally, sympathectomy surgery was carried out as upper thoracic (T2) ganglionectomy, but this is a radical treatment for hyperhidrosis and should be used only when other options have failed. Lumbar sympathectomy surgery is not usually recommended due to the risk of sexual dysfunction.[7] Sympathectomy surgery is particularly successful in palmar hyperhidrosis, with success rates of 92–99%, but the complications are significant, including compensatory sweating in 24–100% of patients, pneumothorax, wound infection, haemothorax, permanent Horner's syndrome, gustatory sweating and intercostal neuralgia (Evidence level: IIb).[7] The advent of endoscopic transthoracic sympathectomy (ETS) made this initially the treatment of choice (Evidence level: IIb)[30] and has reduced some of the risks, but the technique still has to be carried out under general anaesthesia and may not be successful, with approximately 20% of patients being dissatisfied with the outcome following ETS (Evidence levels: IIb).[31,32] One of the primary reasons for dissatisfaction among patients is compensatory sweating, which can occur in up to 26% of patients following ETS (Evidence level: IIb)[33] and which may cause more of a problem than the initial condition being treated.

Iontophoresis. Tap-water iontophoresis using direct current (DC) or DC plus alternating current (AC) has been shown to be an effective treatment for palmar hyperhidrosis, with a reduction in sweating lasting 3–4 days (Evidence level: Ib).[34] The procedure is well tolerated and is usually repeated five to six times a week until the degree of sweating has been reduced to an acceptable level, whereupon maintenance treatment has to be continued once or twice weekly. Iontophoresis is thought to work by blockage of the sweat gland at the stratum corneum level, although structural changes have not been shown.[3] It has also been suggested that the mechanism of action is due to interruption of the stimulus–secretion–coupling, which then leads to a functional disturbance of sweat secretion.[34] However, iontophoresis can cause discomfort (burning and tingling) and skin irritation, including erythema and vesicles, and incorrect use can cause burns at the sites of minor skin injury as well as cutaneous necrosis.[35] Care also has to be taken to avoid electric shock in case of incorrect use.[34,36]

Botulinum Toxin Type A. Although the majority of work has been carried out in axillary hyperhidrosis, botulinum toxin type A has shown efficacy in other types of hyperhidrosis, although only a limited number of patients have been treated to date. In a study by Solomon and Hayman, 20 subjects with recalcitrant palmar and digital hyperhidrosis were treated with botulinum toxin type A (BOTOX®), 165 U per hand. Treatment was shown to reduce sweat production significantly in the treated areas, with anhidrosis lasting from 4 to 9 months, although reduced sweating continued in all patients for the 12-month evaluation period. The greatest reduction in sweating was seen in the nondominant hand (Evidence level: IIa).[37]

Another recent study by Bodokh and Branger compared the effectiveness of treatment with BOTOX® in one hand compared with no treatment in the other control hand. Assessments included subjective and objective measurements using gravimetric scales and Minor's iodine starch test. This study showed a significant improvement in 15/20 (75%) patients treated for palmar hyperhidrosis, with no serious adverse events observed (Evidence levels: IIa, III).[35,38]

Some concern has been expressed that botulinum toxin type A injections in the palm may impede the release of acetylcholine at the neuromuscular junctions, thereby decreasing muscle tone and motor function in the hand; however, this has not been found to be the case (Evidence level: IIb).[39] Lowe et al. investigated the use of BOTOX® vs. placebo for the treatment of palmar hyperhidrosis in 19 patients and concluded that patients experienced a significant improvement in palmar hyperhidrosis without a concomitant decrease in grip strength, significant finger dexterity, or the occurrence of notable adverse events (Evidence level: Ib).[40]

Occasional, transient, generalized muscle weakness in the hands has been reported following treatment for palmar hyperhidrosis, as has pain during injection. Pain during injection can be addressed through application of ice packs, use of the Dermojet delivery system or anaesthetic procedures. Hayton et al. and Naumann et al. conclude that patient preference is for local anaesthetic blockade rather than topical anaesthesia techniques and ice packs.[39,41]

There is a good body of clinical evidence to recommend the use of botulinum toxin type A for the long-term treatment of axillary hyperhidrosis. However, the long-term effects of botulinum toxin type A injections in palmar hyperhidrosis need further investigation, but this treatment appears promising based on current research.

There is more inconsistency in the treatment of palmar hyperhidrosis than in axillary hyperhidrosis and currently no licence exists for botulinum toxin in the treatment of palmar hyperhidrosis. Treatment of palmar hyperhidrosis can be variable due to difficulty in maintaining consistency of injection technique and, as such, the following algorithm is recommended for subjects presenting with palmar hyperhidrosis:

Iontophoresis or botulinum toxin type A
(BOTOX®–100 U per palm)

Sympathectomy

From clinical experience there seems to be a wider range of individual susceptibility to treatment in palmar hyperhidrosis compared with axillary, so the dose needed is more variable. Hayton et al. gives an outline of the neural anatomy relevant to the palmar injection of botulinum toxin type A and provides guidance on appropriate injection techniques.[39] Also, giving botulinum toxin type A injections through the densely innervated skin of the palms is often painful and can deter the patients from repeated treatments. Injections with a Dermojet have been tried in palmar hyperhidrosis in order to reduce the pain, but this technique is not recommended due to the potential for damage to the superficial palmar nerves and vessels.[13,41,42] Therefore, for palmar hyperhidrosis, regional blocking of the ulnar and median nerves at the wrist level with 1% lidocaine is recommended before administering botulinum toxin injections (although training in nerve block techniques should be given to anyone undertaking such techniques).[41]

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