Use of Botulinum Toxin to treat Hyperhidrosis

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Hyperhidrosis is commonly referred to as ‘excessive sweating’ and studies have estimated that 3%1 of the population are affected by this condition. In this article we will concentrate on the armpits (axillary hyperhidrosis), but beware that hyperhidrosis can occur either specifically on the hands & feet (palmoplantar hyperhidrosis) and groin but also secondary generally anywhere on the body.

Aetiology

This condition can either be primary or secondary.

Primary hyperhidrosis normally tend to start in late adolescence and effects men and women equally. Primary hyperhidrosis is caused by an exaggerated response to increased body temperature. Sweating is a natural process mediated by the sympathetic nervous system that the body produces in response to external stimuli, such as heat and stress and is regulated by the hypothalamus. In hyperhidrosis, there is excessive sweating, caused by the hyper function of the eccrine sweat glands, much more than is needed to regulate the body temperature.

Secondary hyperhidrosis may be due to a number of medical conditions such as but not limited to certain medication, hormonal imbalance, thyroid problems, diabetes and obesity

Clinical presentation

You cannot underestimate the physical and psychological2 effects of this condition to the patient presenting to you. I‘ve had some patients that have never worn coloured clothing, due to the sweat patches that will occur. These patients will accommodate their lifestyle to minimise their condition. This condition is extremely debilitating with significant impairment in activities of daily living, social interactions and occupational activities.3

The NHS choices website gives out some helpful,advice to those that suffer from this condition:

- Avoid known triggers that make your sweating worse, such as spicy foods and alcohol.
- Use antiperspirant spray frequently, rather than deodorants.
- Avoid wearing tight, restrictive clothing and man-made fibres, such as nylon.
- Wearing black or white clothing can help to minimise the signs of sweating.
- Armpit shields can help to absorb excessive sweat and protect your clothes.

Sweating is an odourless liquid, however when it decomposes by the action of bacteria, it produces an unpleasant smell.

Diagnosis

A thorough history and examination is needed initially to determine whether you are dealing with primary or secondary hyperhidrosis and whether is it is generalised or localised. The most common type of hyperhidrosis is primary focal hyperhidrosis. Once the diagnosis of primary focal hyperhidrosis is established, we can then evaluate the severity of it.

Secondary hyperhidrosis must be ruled out first before a diagnosis of secondary hyperhidrosis can be made.5

The International Hyperhidrosis Society have produced the hyperhidrosis disease severity scale to assist patients and practitioners before and after treatment.

The patient would rate the severity of their hyperhidrosis:

1 - my underarm sweating is never noticeable and never interferes with my daily activities

2 - my underarm sweating is tolerable but sometimes interferes with my daily activities

3 - my underarm sweating is barely tolerable and frequently interferes with my daily activities

4 - my underarm sweating is intolerable and always interferes with my daily activities

A more scientific and accurate way to test the severity is to establish the rate of sweat production (expressed by milligrams per minute) by the iodine starch test or the ninhydrin test. I would reserve these tests for when the patient is required to be referred to a specialist.

Treatment options

Lasers - Carried out under local anaesthetic, the laser destroys the sweat gland, known as Laser Sweat Ablation

Microwaves - these cause the thermal ablation via dielectric heating6

Pharmarcotherapy - aluminum chloride based antiperspirants will be tried first. Then you can look at anticholinergic agents that inhibit the binding of acetylcholine to the cholinergic receptor and then we have neuromuscular blocking agents - Botulinum Toxin

Botulinum Toxin - licence was granted by the FDA in 2001 for Botulinum Toxin to treat axillary hyperhidrosis. Botulinum Toxin has been proved to be safe and effective for the treatment of axillary hyperhidrosis.7

Botulinum Toxin A (BTX-A) blocks the smooth muscle activity of the sweat glands. BTX-A inhibits acetylcholine release at the neuromuscular junction and in cholinergic autonomic neurons. Compared to treating the face with BTX-A, under the arms seem to have a faster onset of action and greater diffusion.

Studies have shown between a 81.4%8 9 and 76.5% decrease in sweat production two weeks following BTX-A treatment.

Pre treatment

Normal protocols in terms of medical history and consent must be followed. Usual contra indications with BTX-A apply such as pregnancy, breast feeding, medications that may interfere with neuromuscular transmission and neuromuscular disorders. The careful selection of patient is critical to produce the desired result.

The patient is instructed to shave any hair prior to the appointment. In addition they are not allowed to use any anti perspirant 24 hours before their appointment.

Pain associated with these intra dermal injections is reported to be minimal, however a topical anaesthetic can be used to further minimise any potential discomfort.

Different preparations, dilutions and dosages have been reported in different studies. In my experience dilution does not seem to alter the diffusion pattern.

My preferred treatment protocol is to use 0.63ml of 0.9% bacteriostatic saline in 1 vial of Azzalure®. This gives me 125 Speywood units per vial and then I use 1 vial (125 Speywood units) per armpit.

During treatment

The area is throughly cleansed prior to markings - Figure 1

The injected area is marked with a non tattooing pencil - Figure 2. This area is normally darker and indicated by where the hair follicles are situated. In addition ask the patient if they notice sweating coming from any particular areas. A starch iodine test can be considered to accurately delineate the affected area.

Then proceed to mark out as a grid - see Figure 3 - with 1 cm squares. Take a photograph of the markings for future reference. I will then inject the vial of Azzalure® containing 125 Speywood units divided by the number of squares. I use an insulin BD 0.5ml syringe 30G 13mm.

On average I find that there are normally 12 x 1cm square, therefore I would inject 10 Speywood units of Azzalure® per 1cm square.

The injections are placed superficially and intradermally. Regular changing of the needle is required due to the number of injections causing the needle to become blunt and therefore more uncomfortable for the patient.

The most common side effects following treatment (occurring in 3% to 10% of patients) include injection site pain and bleeding, sweating in other parts of the body, flu-like symptoms, headache, fever, itching, and anxiety.

Ask the patient to be aware of any sweating before their review appointment and to pinpoint any specific areas. You may ask them to exercise to increase the body temperature and allow them to sweat and to observe any excessive sweating.

Post treatment

Ask the patient if they have noticed any sweat and to pinpoint the area and then top up accordingly with BTX-A.

In my experience my patients have an average duration of results is 7 months and this is confirmed by numerous studies.10

BTX-A can also be considered for facial hyperhidrosis. This condition can occur on the forehead, upper lip, nasolabial folds and malar areas. When considering the forehead, the injections are placed superficially and high up near the hairline.

Surgery - this should only be considered once all the other options have been explored. The surgical approach consists of destroying the small areas of the sympathetic chain which interrupts the nerves that stimulate the sweat glands. This is also known as ETS - Endoscopic Thoracic Sympathectomy.

Summary

Emerging therapies are being developed constantly to help with the treatment of axillary hyperhidrosis. More research is needed in the field of lasers, ultrasound and radiofrequency.

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