Dear Doctors: 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?

Dear Reader: 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.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: 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?

Dear Reader: 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.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: My husband is 78 years old. A second colectomy left him with one-fourth of his colon, and he suffers from chronic diarrhea. I've read that he should avoid sugar and alcohol, which he won’t give up. Should he see a GI doc, or perhaps a dietitian? I am the cook in our home. How can I help?

Dear Reader: A colectomy is a medical procedure in which a portion of the colon is surgically removed. The colon, along with the rectum and the anus, are all part of the large intestine. Colectomy is used in the treatment of a range of diseases. These can include cancers of the colon or the rectum; inflammatory bowel diseases such as ulcerative colitis or Crohn's disease; the presence of polyps that, due to their size, number or shape, cannot be successfully addressed during a colonoscopy; and in some cases of persistent intestinal bleeding. When it becomes necessary for the entire colon to be removed, this is known as a total colectomy.

Changes to bowel function are among the potential long-term side effects of this type of surgery. The persistent diarrhea that your husband is experiencing is common. Additional symptoms can include dehydration, the production of excess gas and constipation.

The colon absorbs water and nutrients from the digested food it receives and passes the resulting waste to the rectum. A colectomy alters the anatomy of the colon, sometimes significantly. This can lead to an imbalance in the gut microbiome, may adversely affect enzyme function, and can disrupt the complex mechanisms that control the passage of nutrients through the gastrointestinal tract.

You're correct that diet can help to manage the side effects of this type of surgery. Each person will have specific needs, but the basics remain the same. It is recommended that patients eat smaller, more frequent meals, which are easier for the remaining part of the colon to handle. Foods that are known to cause gas, such as beans, legumes and cruciferous vegetables, should be avoided. It's best to also steer clear of greasy, fried and high-fiber foods, which are a challenge to digestion. High-sugar foods can trigger diarrhea. They can also contribute to imbalances in the gut microbiome. Unfortunately for those who enjoy an adult beverage, alcohol acts as a stimulant on the intestines. Drinking can increase both the frequency and the urgency of bowel activity.

We think it would be wise to consult with a gastroenterologist. A specialist will evaluate your husband's medical history, as well as the origin and scope of the disease that led to a colectomy. They can then offer guidance about medications or treatments that may help manage the chronic diarrhea. And because this side effect can arise due to physiological changes to the colon, certain tests may be able to help narrow down a potential cause.

It's also a good idea for your husband to see a registered dietitian. Planning and managing a limited diet that is nutritional and enjoyable is a challenge. Some dietitians specialize in working with colectomy patients. Your medical care provider should be able to help you with referrals.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)