Hyperhidrosis: The Botulinum Toxin Indication That Is Actually Licensed
Most of what botulinum toxin does in an aesthetic clinic is cosmetic, and a good deal of it is off-label. Hyperhidrosis is the exception worth knowing about: severe primary axillary hyperhidrosis is a licensed indication for at least some toxin products in Europe, which puts it in a different category from masseter treatment, and a very different category from softening a line.
That distinction is not pedantry. It changes what you must establish before treating, what you can honestly promise, and what the consent conversation has to contain.
Primary is a diagnosis, not a description
Primary focal hyperhidrosis is excessive sweating beyond thermoregulatory need, without an underlying cause. It typically begins in adolescence or early adulthood, affects specific sites — axillae, palms, soles, sometimes the face — is usually roughly symmetrical, and characteristically stops during sleep.
Secondary hyperhidrosis is a symptom of something else, and the something else can matter a great deal. Thyroid disease, diabetes, infection, lymphoma, medication effects and menopause all appear on that list. The features that should make you stop and refer rather than treat are: onset in later adulthood, sweating that is generalised rather than focal, asymmetry, sweating that continues during sleep, and any accompanying weight loss, fever or night sweats [3].
A patient who sweats heavily at night is not a hyperhidrosis case for an aesthetic clinic. They are a case for their own doctor, and saying so is the most useful thing you will do that day.
Severity is measurable, and measuring it matters
"It's really bad" is not an assessment. Validated severity scales exist for exactly this, and they are short enough to use in an ordinary consultation. They matter for three reasons: they establish that the case is severe rather than merely bothersome, they give you a baseline to compare against at review, and — where reimbursement or a licensed indication is in play — they are the documentation that shows why treatment was appropriate.
Ask about impact rather than volume. Whether a patient changes clothes during the day, avoids certain fabrics or colours, has adjusted their job or their social life — these tell you more than any description of how wet a shirt gets, and they are what distinguishes a medical problem from a preference.
What should be tried first
Topical aluminium salts are the usual first-line treatment, and a patient who has never tried them properly has not exhausted the simpler option. "Properly" is doing some work in that sentence: many patients have used an antiperspirant casually, at the wrong time of day, and concluded it does not work.
Toxin belongs after that has genuinely failed or is not tolerated. Positioning it as the first thing you reach for is both clinically weak and commercially short-sighted, because the patient who was never offered the cheap option remembers.
What the evidence supports
The evidence base here is stronger than for most aesthetic uses of toxin. Systematic review and meta-analysis of randomised trials in primary axillary hyperhidrosis finds consistent reduction in sweat production and improvement in quality-of-life measures, with a safety profile dominated by local, transient effects [1].
What that does not mean is permanence. The effect wears off and treatment is repeated — which is a fact to establish before the first appointment, not after the third month. Patients who understood they were buying a period of relief are satisfied; patients who thought they were buying a cure are not, however good the result was.
Palmar and plantar treatment is a different proposition again: more painful, more technically demanding, and carrying a real risk of transient hand weakness that matters enormously to some occupations. It is not a natural extension of doing axillae well.
Consent is a medical conversation here
Because this is a medical indication rather than a cosmetic one, the consent conversation should read as medical. That means naming the diagnosis and how you reached it, what was tried before, what the realistic duration of effect is, that repeat treatment is expected, the local adverse effects including compensatory sweating elsewhere, and the general contraindications that attach to toxin as a prescription medicine — neuromuscular junction disorders, interacting medications, pregnancy and breastfeeding [2].
Two further points belong in the notes. First, whether the specific product you are using carries this indication in your country: licensing differs between products, and "toxin is licensed for hyperhidrosis" is not the same statement as "this toxin is licensed for hyperhidrosis here". Check the Summary of Product Characteristics for the product in your hand. Second, who is permitted to prescribe and administer it where you practise — a question that is national rather than European, and that a training certificate does not answer.
Why it is worth adding to a practice
Beyond the clinical case, there is an honest commercial one. Hyperhidrosis patients are not comparison-shopping the way cosmetic patients do; they have a problem that has shaped their working life, and they return on a schedule set by biology rather than by fashion. The consultation is also a genuinely medical one, which tends to change how a practitioner is regarded by a patient who arrived expecting a beauty service.
It is, in other words, the part of a toxin practice that looks most like medicine — and that is exactly why it deserves to be learned properly rather than added as a line on a price list.
Training that covers it properly
A course that teaches hyperhidrosis well will spend time on diagnosis and exclusion before it spends any on technique, will teach severity assessment as a documented step, will be explicit about licensed versus off-label sites, and will not present palmar work as a small extension of axillary work. If the session is a slide between glabella and masseter, it is not teaching this indication — it is mentioning it.