A clinical study from the University of Göttingen reports that more than two-thirds of hearing aid and hearing-implant users deal with sweat-related skin problems, and that targeted botulinum toxin injections offered meaningful relief to the small group of patients with severe symptoms.

Most conversations about hearing aids focus on sound quality, fit, and cost. A new clinical study out of the University Medical Center Göttingen turns attention to something far more mundane but, for many users, a daily nuisance: sweat. Sweating on and around the head can irritate the skin under a device, drain the battery faster, and in some cases interfere with how the hearing aid actually works.

The researchers surveyed 51 people who use cochlear implants, active middle ear implants, bone conduction devices, or conventional behind-the-ear hearing aids, and also tested intracutaneous injections of botulinum toxin A (BoNT-A) as a treatment for the small subset of patients with severe head-area hyperhidrosis. The results give a rare, quantified look at how often sweat becomes a clinical problem for hearing device users, and what one evidence-based treatment option looks like in practice.

Background: Why the Researchers Looked at This

People who wear hearing aids or hearing implants almost always have at least one device component sitting on, behind, or embedded in the skin of the head. That skin sweats. For some users, it sweats a lot. When the device is pressed against damp skin for hours at a time, three things can go wrong: the skin can become irritated or inflamed, moisture can seep into electronic components and force the battery to work harder, and, in severe cases, the device itself can malfunction.

Clinicians have long heard these complaints anecdotally, but they have been poorly documented in the peer-reviewed literature. The Göttingen team wanted to put actual numbers to the problem, and to test whether a well-established treatment for underarm and palm sweating, intracutaneous injections of botulinum toxin A, could help patients whose sweat problems were severe. Botulinum toxin, better known by brand names used cosmetically, blocks the nerve signals that tell sweat glands to produce sweat. It has been used for axillary hyperhidrosis for years, but the head and neck area is a newer and less-studied target.

In medical terminology, "hyperhidrosis" simply means excessive sweating beyond what the body needs for temperature regulation. In this study, the term is used specifically for sweat production in the head and neck area that was intense enough to cause clinical problems for hearing device users.

How the Study Was Done

This was a single-center observational study at the ENT clinic of University Medical Center Göttingen. The research team recruited 51 people who use one of four categories of hearing technology: cochlear implants, active middle ear implants, bone conduction devices, or conventional hearing aids. Each participant completed a 12-item questionnaire that asked about sweat production in the head and neck area and any device-related difficulties they could trace to it.

From that pool, six patients reported severe hyperhidrosis. These patients were offered an intracutaneous treatment with botulinum toxin A, delivered in small injections into the skin of the head area most affected by sweat. The researchers then tracked symptom changes and device-function reports after the injections.

Because this was observational and the treatment arm was limited to six people, the study cannot prove broad efficacy or compare BoNT-A against a placebo. What it does offer is a careful description of how widespread the problem is among device users at a major academic clinic, along with an early signal that BoNT-A is well tolerated and subjectively effective in the head and neck area for this specific group of patients.

What the Researchers Found

Sweat problems were common. Twenty-two of the 51 participants, or 43 percent, reported frequent sweating in the head area. Another 17, or 33 percent, reported occasional sweating. Put together, three quarters of this real-world cohort of hearing device users had sweat on the head often enough to notice it.

The consequences were not trivial. Thirty-five of the 51 patients, or 69 percent, reported local skin problems tied to their hearing device, such as redness, irritation, or soreness at the contact points. Sixteen patients, or 31 percent, reported increased energy consumption from their devices, meaning batteries were running down faster than expected. A separate 16 patients, also 31 percent of the group, said their wearing comfort or device function was impaired by the sweat, including cases where the hearing aid itself stopped working as intended during heavy sweating.

In the six patients who received intracutaneous botulinum toxin A injections for severe hyperhidrosis, all reported marked improvement in their symptoms, and none reported any new functional impairment of the hearing device or adverse effects from the injections. This is a small number, but a consistent signal.

The authors concluded that sweat production on the head is an underrecognized source of clinical problems for hearing aid and hearing implant users, and that BoNT-A is an effective, safe, and practical treatment option for the minority of patients whose sweat problems are severe enough to disrupt skin health or device performance.

What It Means for People with Hearing Loss

For readers, the most useful finding from this study is the simple fact that sweat-and-device problems are normal and very common. If your hearing aid irritates the skin behind your ear during the summer, drains its battery faster than the manual suggests, or sometimes cuts out when you have been exercising or working outside, you are not imagining it and you are not alone. Roughly seven out of ten hearing device users at this clinic reported at least some skin problems tied to their device.

The second takeaway is that there is a medical option, BoNT-A injections delivered into the skin of the head area, that audiologists and ENT physicians can consider for patients whose sweating is severe enough to cause recurring skin or device problems. It is not a first-line solution, and it is not something every clinic offers, but it is a legitimate option worth asking about rather than silently suffering through hot weather.

The third, practical takeaway has to do with form factor. Every category of device studied here, conventional behind-the-ear hearing aids, cochlear implants, middle ear implants, and bone conduction systems, shares one thing: a component that sits on the outer skin of the head or behind the ear. It is that contact surface, and the sweat that pools against it, that drives the problems.

Why Form Factor Matters: Addressing the Behind-the-Ear Contact Problem

The Göttingen study's central observation is that sweat against a device component sitting on the head is what drives skin irritation, battery drain, and occasional malfunction. One way that newer over-the-counter (OTC) hearing aids approach this issue is by moving the device off the skin behind the ear and into the ear canal itself. The FDA-OTC hearing aid category, approved in the United States in 2022, opened the door to smaller in-canal form factors at a fraction of the price of traditional devices, and several of those designs address the contact-surface problem by simply not having a behind-the-ear component.

Panda Stealth, a 2.3-gram invisible in-the-canal OTC hearing aid, is one such device. It sits entirely inside the ear canal rather than on the skin behind the ear, uses 12-band smart noise reduction, and comes with a charging case that doubles as a wireless remote. It is backed by a 5-year warranty and a 45-day return window. For people whose chief struggle with a behind-the-ear aid has been sweat against the skin, an in-canal design is a form factor worth considering.

A caveat worth naming clearly: OTC hearing aids, including in-canal designs, are approved for adults with perceived mild-to-moderate hearing loss. They are not intended to replace the cochlear implants, middle ear implants, or bone conduction systems described in this study, each of which serves people with more severe hearing needs and specific anatomical circumstances. Patients with severe or profound hearing loss, or those who already use an implanted system, should continue to work with their ENT and audiology team on issues like hyperhidrosis, and BoNT-A injections may be an option worth raising at their next clinic visit.

Limitations of This Research

This was a small, single-center observational study. Fifty-one patients at one German university ENT clinic is a useful first look, but the group is not a representative sample of the global hearing device population. The treatment arm, six patients, is far too small to draw any firm conclusions about how broadly BoNT-A should be used, and there was no placebo-controlled comparison. Self-reported symptom improvement after a known injection is also susceptible to placebo effects.

The study also did not systematically break down results by device type, so we cannot say from these data alone whether, for example, bone conduction users reported more or fewer problems than conventional hearing aid users. A larger, multicenter, randomized study would be needed to answer those questions and to establish standardized dosing and injection sites for BoNT-A in the head and neck area for this indication. The paper is published in Laryngo-Rhino-Otologie; no unusual conflicts of interest are flagged in the author affiliations, all of which are at a single academic department.

Where This Leaves Us

If you wear a hearing aid or an implant and deal with recurring skin irritation, faster-than-expected battery drain, or device hiccups on hot days, this study is a good prompt to bring it up with your audiologist or ENT rather than treating it as an unavoidable part of wearing the device. Options range from simple hygiene adjustments and skin-friendly device sleeves, to switching form factor, to, for the minority of users with severe hyperhidrosis, discussing whether BoNT-A injections fit your case. The Göttingen group has said they plan to continue studying this area, so it is worth following how their work develops.

Shahpasand S, Laskawi R, Blum J, Strenzke N, Oestreicher D, Beutner D. Botulinum toxin reduces sweat-related problems for hearing aid users - a clinical study. Laryngo-Rhino-Otologie. 2026. Retrieved from PubMed. DOI: 10.1055/a-2850-4392.