The Causes of Hyperacusis

Sound sensitivity most commonly manifests following some sort of trauma to the ears. For example, if you're a bartender at a nightclub, you may find your hearing growing more and more sensitive when you're not behind the bar. Certain drugs may also cause the condition to manifest, as well.

Hyperacusis has also been linked to other forms of trauma, such as head injury or surgery. There are also multiple illnesses that can cause the condition, including Meniere's Disease, Lyme Disease, and inner ear infections. Hyperacusis can also manifest as a birth defect, though this is incredibly rare.

What Hyperacusis Feels Like

First and foremost, we need to dispel a common misconception about hyperacusis, Having the condition does not mean you've suddenly developed superhuman hearing. Your ears don't function any more effectively than in someone without the condition, even though they may feel like they do.

Although the human ear is capable of tolerating sounds of up to 70 decibels (dBA) without injury, we're usually capable of dealing with noise levels a bit higher — around 90 dBA — without discomfort (although this is not recommended). That's about the volume of a subway or a lawnmower. People with hyperacusis, on the other hand, can drop to 60 dBA or lower.

That means they can't even tolerate regular conversation.
Hyperacusis is usually triggered by common, everyday noises. The ringing of a telephone, a hairdryer, music on the television, or even a barking dog can cause discomfort. Where it differs from misophonia is in its scope — hyperacusis is much more general, whereas misophonia is triggered by a very specific, repetitive noise.
It's also worth noting that hyperacusis tends to be linked to mental illnesses like anxiety and depression. As noted by the National Center for Biotechnology Information, it occurs frequently with conditions like depression, exhaustion, post-traumatic stress disorder, and generalized anxiety disorder. It can often occur alongside conditions like tinnitus, as well. 

How Hyperacusis is Treated

Generally speaking, hyperacusis cannot be treated through drugs or surgery, and earplugs generally do not alleviate it. Instead, treatment for the condition is more often focused on the mental side of things. Sound therapy, for instance, has proved quite effective.
Simply turn on a white noise machine while you sleep, using headphones to maximize its effectiveness. You can gradually increase the volume of the device week after week. Eventually, your brain will start to 'reset,' and you'll begin to develop a tolerance to the painful sounds.
As mentioned, tinnitus and hyperacusis are often linked. As such, any technique that is effective at treating tinnitus can usually be applied to hyperacusis. At the end of the day, the best thing you can do is contact an ear, nose, and throat specialist or audiologist — they will be able to tell you a great deal more, and help you explore potential treatments.