Sweat is a solution of water and salts produced by glands immediately under the skin and cools the body by evaporation during exercise and in warm surroundings. The activity of these glands is normally controlled by the nervous system. In a small number of people (less than 1.0% of the population), this control mechanism fails to function normally causing excessive sweating, even when body temperature is normal. This condition is known as hyperhidrosis.

Occasionally, hyperhidrosis occurs as a result of abnormal hormone levels and these will be measured as part of the assessment of people with this condition. In most cases, no reason for the excessive sweating will be identified by these tests. 

Excess sweating may occur anywhere but usually affects the hands, armpits, scalp, face, and/or feet. Although some people may find this excess sweating embarrassing, it is not a dangerous or life threatening condition.


The principle means of treating this condition are the use of potent antiperspirants, surgery and Botulinum toxin injection (Fitzgerald et al. 2004 )


The most effective antiperspirant is Aluminum Chloride - typically Anhydrol Forte(TM) - which may be prescribed for you. This is applied in the evening 2-3 times per week and washed off the following morning. In some cases, it causes skin irritation. The treatment must be repeated regularly for life. This agent cannot be used on the face or scalp.

Botulinum toxin injection 

This treatment is suitable for people who find the topical antiperspirants ineffective or develop skin problems when using them. Its is a safe and effective treatment for underarm hyperhidrosis. This procedure is performed using local anaesthesia in the day ward or outpatient department. The evening before your procedure you should carefully shave your underarm area. Do not apply antiperspirants or deodorants. If you have been given a local anaesthetic preparation, apply this in the morning before you leave home to attend the clinic. Cover the local anaesthetic cream with an occlusive dressing (which was also supplied)  

On the morning of your procedure you will be asked to attend the OPD. If you have not been given a local anaesthetic cream to apply at home, local anaesthetic cream (Ametop) will be applied to the area and covered with an occlusive dressing.  The procedure only takes a few minutes and consists of a number (10-12) of tiny injections into the skin under each arm. These injections may cause minimal discomfort. The botulinum toxin binds to the nerve endings and prevents their effects on the sweat glands.  

The injections may take several days to work. During this time you should not shave but may use antiperspirants or deodorants. The nerve endings begin to regrow 6 to 9 months after the injections and you may notice recurrence of the sweating. You may be booked for a repeat treatment before you leave the clinic or an appointment will be sent out to you in the post. 


While allergic reactions can occur, these are not common. There is a theoretical risk of developing botulism from botulinum toxin injections. This is a very serious illness that can be life threatening but this has never been described with the preparation that we use in our clinic (Botox, Allergen).

Occasionally, the treatment is ineffective and must be repeated. 

It is possible that, over time, patients may develop antibodies to botulinum toxin which will prevent the treatment having any effect. 

However, in several studies in large numbers of patients, we have shown that Botulinum Toxin is a cost effective treatment over at least 5 years (Lynch et al 2020; Gibbons et al. 2016).


The surgical procedure used in the treatment of severe hyperhidrosis is called endoscopic thoracic sympathectomy (ETS) or TTEC (trans thoracic electrocoagulation). Complications are common and this procedure is now rarely used for the treatment of axillary hyperhidrosis.



Fitzgerald E, Feeley TM, Tierney S. Current treatments for axillary hyperhidrosis. Surgeon. 2004;2(6):311-360. doi:10.1016/s1479-666x(04)80028-3

Gibbons JP, Nugent E, O'Donohoe N, et al. Experience with botulinum toxin therapy for axillary hyperhidrosis and comparison to modelled data for endoscopic thoracic sympathectomy - A quality of life and cost effectiveness analysis. Surgeon. 2016;14(5):260-264. doi:10.1016/j.surge.2015.05.002

Lynch OE, Aherne T, Gibbons J, et al. Five-year follow-up of patients treated with intra-dermal botulinum toxin for axillary hyperhidrosis [published online ahead of print, 2020 Jan 3]. Ir J Med Sci. 2020;10.1007/s11845-019-02131-3. doi:10.1007/s11845-019-02131-3)