Y. Zhou, MD, Ph D, FRCPC (Dermatology)
The Hyperhidrosis Clinic, Division of Dermatology, University of British Columbia, Vancouver, British Columbia, Canada
Hyperhidrosis refers to the excessive production of sweat. There are many forms of hyperhidrosis, affecting a large proportion of the general population. Until recently, treatment was difficult; however, new advances such as a selective neurotransmitter blockade with botulinum toxin injections have revolutionized the management of many patients suffering from this condition.
Primary focal hyperhidrosis (PFHH) is the most common form of hyperhidrosis and is defined as non-physiological excessive sweating that occurs symmetrically in a localized fashion. Affecting about 5% of the general population, PFHH most frequently affects the axillae, hands, and feet. Other areas, such as the face and the groin, can also be involved. Although it does not endanger the life or physical health of an affected individual, it can cause significant negative impact on the quality of life. Patients most frequently report difficulty with work, school, and social relationships and as a result, they often shy away from situations that require shaking hands or other forms of close physical contact with people.
Several forms of treatment are available for the management of PFHH. Depending on the locations involved, the options are slightly different.
- The most commonly used first-line treatment for axillary PFHH. For example, aluminum chloride 20% solutions applied once or twice daily on affected areas (on dry skin to decrease irritation) can be used.
- Rarely offer significant or complete relief of the sweat production.
- Frequent reports of local irritation.
- Preferred by most patients because of relatively low cost.
- Central reagent is aluminum chloride in various concentrations: the higher the concentration is, the more effective it is. However, higher concentrations are also associated with higher risks of local irritation, which can limit compliance.
Subcutaneous Injection of Botulinum Toxin
- Botulinum toxin, when injected by experienced physicians, blocks the release of acetylcholine, a neurotransmitter, by the sympathetic nerves innervating the sweat glands.
- Localized effect to the immediate areas of the administration, with little systemic spread.
- No significant side-effects.
- More than 90% reduction in sweat production for more than 90% of patients.
- Repeated injections necessary, usually one to two injections each year.
- Relatively high in cost. However, since all private health insurance carriers cover the cost of the drug for this indication, it can be offset for anyone who has a private drug plan. In addition, an injection of botulinum toxin eliminates the frequent use of topical antiperspirants and potentially saves costs associated with replacement of clothing. The cost associated with the botullinum toxin injection is only marginally higher than the cost of topical antiperspirants.
Oral anticholinergics such as glycopyrolate can offer mild-to-moderate relief for some patients suffering from PFHH. However, because of the systemic side-effects such as dry mouth, blurred vision, and reduced gastrointestinal motility,
systemic anticholinergics have not been the accepted therapy for most patients.
Surgical Management of Axillary Hyperhidrosis
Surgical removal of the sweat glands in the axillae, or ablation of the sympathetic chain supplying the sweat glands can also be performed for selected patients. However, there are concerns of surgical complications such as:
- With sweat gland removal
– relapsed sweating.
- With sympathectomy
– risk of intrathoracic injury to the lungs and other nerve structures
– compensatory hyperhidrosis.
Therefore, these procedures are generally reserved for patients who do not respond to other forms of therapy.
Hyperhidrosis affecting the hands and the feet is also very common, alone or in combination with axillary hyperhidrosis. The treatment options are similar to those for axillary hyperhidrosis.
- Topical antiperspirants are often the first therapy tried.
– Rarely satisfactory.
- Botulinum toxin subdermal injections are highly effective.
– Cost of therapy significantly higher because palmoplantar hyperhidrosis requires significantly larger doses of the toxin.
- Tap-water-iontophoresis treats the palms and soles of the affected individual with micro-amounts of electric current delivered through the medium of tap water. The mechanism of action is unknown. However, it may involve formation of plugging of the eccrine sweat gland pores.
– Initially requires frequent treatment sessions to be effective.
– Once significant control of sweating is attained, infrequent maintenance therapy is all that is necessary for moderate-to-significant long-term control.
– Relatively low in cost.
– No significant side-effects.
– May be tried by patients before sympathectomy.
As for axillary hyperhidrosis, systemic anticholinergics can be used when other nonsurgical options are not effective or suitable.
Excessive production of sweat of the face and scalp can be a significant concern for many individuals.
- This area is not suitable for topical antiperspirants or iontophoresis.
- The most effective therapy is botulinum toxin sub-dermal injections.
- Especially effective and safe for the forehead and scalp, where the side-effect of facial muscle paralysis is not a big concern.
- For the lower face, careful placement of the toxin is required to avoid untoward paralysis of the facial muscles.
Systemic anticholinergics such as glycopyrolate can also be tried for patients when botulinum toxin is not an acceptable choice.
There have been major improvements in the treatment of excessive production of sweat because of the introduction of effective botulinum toxin therapy. For facial and axillary hyperhidrosis, this has become the treatment of choice for most patients. For palmoplantar hyperhidrosis, botulinum toxin is also highly effective and should be offered along with the choice of iontophoresis if topical therapies fail. For both axillary and palmoplantar hyperhidrosis, surgical options are reserved as the last options when all other treatments fail.