Is There A Link Between Chemical Exposure And Tinnitus?

Chemicals are defined as “a substance obtained by a chemical process,” referring to the scientific study of the composition, structure, and properties of substances. There are many ways in which chemicals can influence a person’s bodily functions and processes. More specifically, there are certain chemicals which may interact with our hearing systems (specifically, the hair cells of the inner ear) in negative ways that result in damages to hearing or decreased hearing health. The American Speech Language and Hearing Association compiled a list of chemicals known to cause hearing loss, tinnitus, and/or balance issues.

Chemical exposure can happen in a variety of ways including ingestion, inhalation or through skin absorption – you can click here to view The CDC’s published list of chemicals known to cause hearing loss. How exactly does chemical exposure lead to hearing loss and other bodily damages? Ototoxic exposures (chemical exposure which cause harm to the inner ear structures) can occur in a variety of ways. Although chemical induced hearing loss may not be common, it can have a significant impact on a person’s overall  hearing function and be a large contributor to sensorineural hearing loss.

Medications Containing Ototoxic Chemicals

A substance is identified as ototoxic if it is known to cause damage to the structures of the ear. Ototoxic chemical exposure can result in hearing loss, tinnitus, and/or balance disturbances and, according to the American Speech Language and Hearing Association, these effects can be either temporary or permanent. Some common examples of ototoxic medications include aminoglycoside antibiotics (such as gentamicin or amikacin), platinum-based chemotherapeutic agents (such as cisplatin or carboplatin), loop diuretics like ethacrynic acid or furosemide, and macrolide antibiotics (such as azithromycin or erythromycin, and antimalarials (such as quinoline-type drugs).

The ototoxic effects of drugs such as the ones listed above are frequently dose-dependent, meaning that the degree to which they affect hearing and the severity of any other impacts are related to the amount of the drug that is administered. A recent article published by the American Speech Language and Hearing Association suggested that ototoxic medications can produce abnormal neural activity within the auditory nerve structures and other brain structures that results in the perception of tinnitus. Anyone taking medications that are known to contain ototoxic chemicals should be referred to an audiologist who can help them to manage any hearing, tinnitus, or balance issues that may occur as a result of treatment and enroll them in a hearing conservation program.

Ototoxic chemicals are present in a variety of household items and not only found in medications, however, chemical induced hearing loss may be more common among those who experience hearing loss as a result of chemical exposure in medication than in other substances.

Chemical Solvents And Hearing Damage

Solvent materials may contain substances like benzene, styrene, or toluene. Solvent exposure is shown to have negative impacts on human bodies–which may include hearing health and lead to hearing loss or tinnitus. These materials are often used in products such as plastics, paints, cleaning agents, cigarette smoke, fiberglass, insulating materials, adhesives, rubber, and spray paints. A 2019 article discussing the occurrence of tinnitus in firefighters mentioned benzene exposure (from burning buildings) as a possible contributing factor to the development of tinnitus. However, another 2019 article looking specifically at the relationship between organic solvents and tinnitus found no significant relationship between the two, although they did note a relationship to hearing loss. Hearing loss is a known risk factor for tinnitus, so there may at least be an indirect relationship.

Ototoxic chemicals cause hearing loss in a few important ways, which makes it important to prevent exposure to these types of chemicals to prevent solvent induced hearing loss. While loud noise is a common occupational hazard associated with tinnitus sufferers, chemical solvents are another possible risk found in the workplace. Noise induced hearing loss is frequently discussed in articles evaluating tinnitus causes, but ototoxic chemical exposure may not be as frequently discussed.

Carbon Monoxide

The Centers for Disease Control and Prevention defines carbon monoxide as an odorless and colorless gas, produced when burning various materials such as in stoves and fireplaces. Thankfully, carbon monoxide detectors are easily accessible at local stores, offering an effective way to detect and prevent prolonged exposure. Carbon monoxide poisoning can lead to a variety of symptoms like hearing loss, tinnitus, and balance problems.

A recent case report showcased a 34-year-old man who suffered from unilateral pulsatile tinnitus and vertigo due to exposure to natural gases. Surprisingly, while many people associate noise exposure with tinnitus, few connect carbon monoxide with inner ear damage and subsequent hearing loss. This link often remains unexplored since chemical exposure is not commonly tied to hearing deficits. Yet, dangerous exposures can lurk in the most everyday settings. When hearing loss occurs and it’s not evidently age-related or linked to a clear cause, investigating the potential presence of certain chemicals might be a worthwhile course of action.

Pesticides And Hearing Loss

According to the Environmental Protection Agency (EPA), pesticides are substances intended to prevent, destroy, repel, or mitigate pests. These substances may contain chemicals such as carbon disulfide or trichloroethylene. Individuals who have been exposed to carbon disulfide reported being woken up by tinnitus and those with trichloroethylene poisoning have also reported a variety of effects, including tinnitus. This can be one way chemicals are linked to work related hearing loss, as outdoor workers exposed to pesticides are not uncommon, but pesticides can also be found in schools and homes, making it possible for certain chemicals to be found among people who do not necessarily know they are potentially exposed to ototoxic chemicals.

The Environmental Protection Agency (EPA) defines pesticides as substances used to prevent, repel, destroy, or mitigate pests, which often contain chemicals such as carbon disulfide or trichloroethylene. Notably, individuals exposed to carbon disulfide have reported tinnitus, waking them from sleep. Similarly, those poisoned by trichloroethylene have experienced various symptoms, including tinnitus. Such chemical exposures can contribute to work-related hearing loss, especially among outdoor workers. However, pesticides are also present in schools and homes, suggesting that even individuals unaware of their exposure could be at risk from ototoxic chemicals.

Tobacco Smoke And Hearing Disorders

Cigarette smoke is widely recognized as a health hazard that poses significant negative effects, including an increased risk of cancer and cardiovascular disease. It has also been linked to a variety of auditory issues, including measurable dysfunction of the cochlear hair, and has strong links to tinnitus. A hearing conservation program is likely to be one that includes encouraging participants to support the health of hair cells by avoiding certain chemicals and compounds, including those found in tobacco smoke. Fortunately, most effects of tobacco smoke and even secondhand smoke can be limited when the habit is stopped altogether, or the environment is removed.

Other Sources Of Chemical Exposure

Skincare products can also be sources of chemical exposure. While some chemicals are deemed safe for skincare and wellness, others have not been thoroughly vetted. Distinguishing between the two can be challenging, especially given the limited regulatory oversight on ingredients, unless specific concerns already exist. Third-party testing and lab evaluations are helpful in identifying potentially ototoxic ingredients in personal products. Although these exposures might not be as intense as those from daily contact with ototoxic chemicals in a work setting, they can still harm the health of ears and hair cells, leading to potential ototoxicity.

Additional Tinnitus Considerations

Tinnitus treatment can be as simple as removing potentially ototoxic medicines from your medicine cabinet, removing known ototoxic chemicals from your personal care, home care, and lawn care items, but can also be more involved. Removing hazardous chemicals can be an important step–especially for exposed workers–but there are other interventions that can help limit the effects of tinnitus considerably. These interventions commonly include the following:

• Sound therapy. Sound therapy is a type of therapy that utilizes sounds to effectively mask the sounds of tinnitus for an individual. Sound therapy can be delivered in a hearing aid or through a table top machine, in order to most effectively “cover” the sounds of your tinnitus.
• Cognitive Behavioral Therapy (CBT). CBT is a mental health intervention that can help alter responses to tinnitus symptoms. While CBT cannot meld dis-connected neural pathways, it can help reduce the emotional and mental harm that can come as a result of tinnitus.
• Tinnitus Retraining Therapy (TRT). TRT combines counseling and sound therapy, in order to deliver the best of both worlds. TRT is typically delivered using hearing aids, and does require the intervention of an audiologist for best results.

The combined exposure of noise and hazardous chemicals can truly spell trouble for those in search of healthy hearing. Addressing both concerns, fortunately, can help limit the effects of solvent exposure and noise exposure, in order to better support the health of your ears and auditory system.

Conclusion

Exposure to various chemicals can result in hearing loss, tinnitus, and balance disturbances. It’s essential to use personal protective equipment, monitor hearing regularly for changes, and reduce exposure to potential hazards. While some sources of hearing impairment lead to irreversible damage, others can be managed or even prevented by wearing proper hearing protection, avoiding skin absorption, and choosing non-toxic personal care and cleaning products. While the dangers of loud noise are commonly discussed, many aren’t aware of the ototoxic effects of certain chemicals. Ensuring limited exposure to both loud noises and ototoxic substances is a key defense against hearing loss and the onset of tinnitus.

Regardless of the cause of your tinnitus, the Treble Health team can help. If you have any tinnitus related questions, whether it be about prevention, diagnosis, or treatment options, we encourage you to schedule a complimentary telehealth consultation with one of our audiologists. This free, 20 minute Zoom call is a no-strings-attached opportunity to get personalized information regarding your specific situation.