Based on an interview with Sydney dermatologist, Dr Rob Rosen conducted at the Annual Women’s and Children’s Health Update, Sydney in February 2018.Hyperhidrosis is a very distressing condition that equally affects both men and women, across all ethnicities.  It occurs in approximately 3% of the general population and the onset is in childhood or adolescence. However, only about one third of people affected seek medical advice.In addition to the physical effects, the psychological impact on affected individuals is significant. Embarrassment, anxiety and depression are very commonly associated with this condition.In primary hyperhidrosis, the sweat glands are normal but there is an apparently exaggerated sympathetic response. The sweat glands most susceptible to these sympathetic cholinergic effects are the eccrine glands found in the palms, soles and axillae.Primary, focal hyperhidrosis tends to be bilateral and symmetrical, occurring at least once a week. It usually commences before a person reaches their mid-twenties and is often familial.  In its typical form, and if there is nothing to suggest a secondary cause, it requires no investigations.Secondary hyperhidrosis is typically generalised, affecting the entire surface of the skin. By definition, it has an underlying cause, such as infection, endocrine disturbance, neuropathy, malignancy, menopause, drug withdrawal or the side-effect of medications.  A full history, examination and targeted investigations are required before this condition can be called idiopathic.“It is important to make the distinction between “generalised” and “focal” hyperhidrosis at the outset,” says Sydney dermatologist, Dr Rob RosenThe management of hyperhidrosis begins conservatively. By the time they present to a doctor they usually have already tried a range of antiperspirants.  Aluminium hydroxide 20%, topically, daily for four weeks should be trialled before further treatment is considered. Many patients develop localised irritation to this treatment, as it obstructs the eccrine ducts, causing their atrophy.The most effective management is Botulinum A toxin injections. This drug blocks the release of acetylcholine from presynaptic nerve terminals, thus inhibiting the stimulation of the eccrine sweat gland.The injections are done intradermally and retreatment is needed approximately every six months. Over time, this duration between treatments may become longer.Side effects include discomfort at the injection site and, less commonly, weakness of local muscles (especially relating to small muscles in the hand, for example, in palmer hyperhidrosis). In the research done by Dr Rosen t al, over 90% of patients were happy with this therapy.¹Oral anticholinergics such as oxybutynin (5mg to 15mg daily) or glycopyrrolate (1mg to 4mg daily) may be used and are most effective in refractory cases of generalised sweating.The anticholinergic side effects (urinary retention, dry mouth, constipation) tend to be a limiting factor in their use.Other treatments for hyperhidrosis tend to be either less effective or more invasive.For patients over 12 years old, there is a Medicare rebate for Botulinum A injection therapy for severe primary axillary hyperhidrosis, if aluminium hydroxide has failed and if it is administered by a dermatologist, neurologist or paediatrician. Some cosmetic clinics treat patients without a rebate and this is often a more expensive option.

1. Rosen R, Stewart T. Results of a 10-year follow-up study of botulinum toxin A therapy for primary axillary hyperhidrosis in Australia. Intern Med J; 48;343-347.