Swimmer's ear triggered by moisture in the auditory canal

Q: Our 12-year-old son loves swimming. He's in the pool all year, without any problems. This summer, he started taking surfing lessons, and he got a pretty bad earache. His pediatrician diagnosed swimmer's ear. Did switching from the pool to the ocean have anything to do with it?

A: Swimmer's ear is a term that describes inflammation or infection in the external auditory canal. That's the portion of the ear between the eardrum and the outer ear. The medical term is otitis externa, and it is sometimes shortened to OE.

Swimmer's ear often arises due to moisture that gets trapped in the curves and crannies of the ear canal. This creates the ideal environment for a bacterial infection, which is the most common cause of swimmer's ear. It's less common, but swimmer's ear can be caused by a fungus as well. The name of the condition refers to swimming, which for much of the U.S. suggests a pool. However, the trigger is any type of moisture that lingers in the ear. It can come from any source. This includes a pool, the ocean, a lake, a shower, a bath, perspiration or even persistent humidity.

Symptoms of swimmer's ear include redness, pain, swelling or itchiness in the external ear canal. Some people experience a feeling of fullness in the ear. The condition can lead to muffled or reduced hearing and can cause a humming or buzzing sound. More severe infection can result in a swollen gland in the neck, fever and the presence of pus in the ear canal. Diagnosis is made with a visual inspection of the outside and inside of the ear. A lighted instrument known as an otoscope may be used to look deeper inside the ear. Sometimes, the eardrum may appear inflamed or swollen. When pus is present, the doctor may collect a sample for analysis.

Treatment focuses on clearing up the infection and managing any discomfort. This typically includes the use of antibacterial ear drops. If the infection is fungal in origin, antifungal ear drops, such as fluconazole and clotrimazole, may be prescribed. Corticosteroid drops may also be used to manage swelling and itching. If discomfort is severe, over-the-counter pain medications can be helpful. With prompt treatment, the condition usually clears up in a week to 10 days. However, it's important to adhere to the schedule of medication, and to keep the ear canal clean and dry.

The use of ear plugs when swimming or taking part in other types of water activities can help prevent swimmer's ear. This can be particularly useful for your son as he pursues his interest in surfing. The infection of swimmer's ear sometimes arises due to scratches or cuts that are present in the outer ear canal, so take great care when cleaning the area. After immersing his head in water, he should tilt the head and allow any excess water to exit the ear. Specially formulated ear drops that dry the ear canal are also available. You can check with your son's pediatrician as to whether these might be helpful for him.

Q: My boyfriend says that lately I've been talking in my sleep and sometimes acting out my dreams. One time I actually hit him. He says it may be something called an REM sleep behavior disorder. This has been kind of scary, and I would like it to stop. Would going to a sleep clinic help?

A: Sleep disorders are estimated to affect up to 70 million people living in the U.S. They include insomnia, which is the most common sleep disorder, restless leg syndrome, obstructive sleep apnea, narcolepsy and parasomnias. REM sleep behavior disorder, also known as RBD, falls into that last category.

The term parasomnia refers to abnormal behaviors that occur during sleep. Sleep talking, sleep paralysis, bed-wetting, repetitive tooth grinding, sleepwalking and nightmare disorder are also considered to be parasomnias.

REM is short for "rapid eye movement." REM sleep is one of the four stages of a complete sleep cycle. During REM sleep, the majority of dreaming occurs. Scans of sleeping individuals show a significant amount of brain activity during REM sleep, almost as much as what the person would exhibit while awake. At the same time, signaling mechanisms within the brain induce a type of muscle paralysis in the sleeping individual. This is known as atonia. Sometimes referred to as REM sleep muscle paralysis, atonia is a normal, and even necessary, part of REM sleep.

When someone has REM sleep behavior disorder, it means that the safeguard of atonia, or sleep muscle paralysis, has been breached. This allows the person to physically respond to, or act out, their dreams. The resulting activity can range from small movements, such as waving a hand, to vigorous, full-body engagement. When it is the latter, it can put the sleeper, as well as those around them, in danger. Someone with RBD may thrash, kick, hit or punch. This can potentially cause injury to themselves or to their bed partner. When they awake, they will also often clearly remember the dream they had been having.

Diagnosis of a sleep disorder typically includes a medical history and a detailed sleep history, and may also involve a physical exam and a neurological exam. A sleep study, during which the individual's physiological and behavioral data are recorded, is also often requested.

When someone has RBD, the data collected in a sleep study will often reveal a lack of atonia, or sleep paralysis, during REM sleep. Treatment of the condition focuses on changes to the sleep environment to make it safer, and on the use of medications. These can include melatonin, a hormone that helps regulate the sleep cycle, and certain anti-anxiety medications.

The causes of RBD are not yet understood. In some cases, they have been linked to neurological disorders and to the use of antidepressants. Some people find that the episodes are temporary and recede on their own. If your symptoms persist, you should consult with your health care provider. If needed, they can refer you to a sleep clinic for an in-depth assessment and any necessary treatment.

Q: I was rubbing my face and a cluster of new floaters appeared in my right eye. There's also an arc of light when I look from side to side. I'm told it might be vitreous detachment and that it can damage my retina. I've never heard of this. Is it common? Can it heal or be repaired?

A: Posterior vitreous detachment, also known as PVD, can occur at any point in life. It can occur due to trauma and certain health conditions, but it is usually associated with older age. Risk begins at about age 50. As people reach their 70s and 80s, the condition becomes more common.

PVD usually does not adversely affect eyesight. However, in some cases it can result in damage to the retina. To understand the risks it can pose, we should begin with a bit of anatomy.

The eyeball is a rounded orb. The portion that we see - a colorful iris set in an ovoid of white with a black pupil at its center - accounts for just one-sixth of it. The rest sits sheltered in the bony socket of the skull. It's there that the structures involved in PVD are located. The lens divides the interior of the eye into two distinct cavities, one in front and one in back. The larger of these, toward the rear of the eye, is known as the vitreous cavity. It's filled with a clear, gelatinous fluid enveloped by a protective membrane. The vitreous humor also contains a matrix of collagen fibers.

The vitreous cavity is backed by the retina, which is made up of layers of light-sensitive cells. The retina also contains a tiny area of specialized cells known as the macula, which is responsible for our detailed central vision. Working together, the retina and macula turn light captured by the structures at the front of the eye into energy. The optic nerve delivers these impulses to the brain, which translates them into visual images.

Remember those collagen fibers in the vitreous humor? They help anchor it to the retina. As we age, the vitreous humor begins to shrink. This causes it to separate from the retina and the collagen fibers to break free. This process, which is irreversible, is known as posterior vitreous detachment. Symptoms include the increase in floaters that you experienced, as well as the arcs of light. These usually decline over the course of several weeks.

In most cases, PVD occurs gradually and does not pose a threat to the retina. But if detachment occurs suddenly, or if a portion of the vitreous humor adheres, it can cause a tear in the retina or a retinal blood vessel. It can also escalate to retinal detachment. In either case, surgery would be necessary.

Due to these potential complications, it's important to see a retina specialist when symptoms of PVD occur. The doctor will conduct a dilated eye exam to check for damage to the retina and may request more detailed imaging tests. It is also likely they will recommend repeated checkups in the coming months until the vitreous has completely and safely detached without complications.

• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.