Dear Doctor: Are cold sores and herpes the same thing? I’ve got both, and finding out there’s no cure really stinks. My friends say lysine can help. Is that true?

Dear Reader: Cold sores and genital herpes are caused by different types of the herpes simplex virus, or HSV. Each type is quite contagious.

HSV-1 causes cold sores on the lips and mouth. It’s estimated that half of the population in the United States is infected with the oral herpes virus. The majority of genital herpes, which is a sexually transmitted disease, is caused by HSV-2. The infection rate of HSV-2 in the U.S. is estimated to be at least 15 percent and as high as 20 percent. Some cases of genital herpes are caused by HSV-1, as the virus can be spread from the mouth to the genitals.

You’re correct that at this time, there is no cure for either type of herpes infection. Instead, people who have frequent outbreaks seek to manage the condition. Many people infected with HSV-2 rely on antiviral medications, which can shorten or suppress outbreaks of genital herpes and also lessen symptoms when an outbreak does occur. The three main drugs are acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex). Antivirals may also be prescribed to people infected with HSV-1 who are having frequent or severe outbreaks. The over-the-counter cream Abreva, which targets oral herpes, can be useful at curbing an outbreak when used at the first sign of symptoms.

When it comes to lysine, there is both scientific and anecdotal evidence regarding its efficacy in diminishing the frequency of herpes outbreaks. The results of the earliest yes-it-works lysine studies, which date back to the 1970s and ‘80s, have been replicated in subsequent studies over the years. And the first time we wrote about HSV-2 in this column and didn’t mention lysine, we got a flood of letters from readers with testimonials as to its usefulness. However, due to conflicting data regarding whether lysine will also decrease the severity or duration of an outbreak, that particular effect remains up for debate.

Lysine is what is known as an essential amino acid. Amino acids are the organic compounds from which proteins are made. Of the 20 amino acids we humans require, 11 are produced by our bodies. The remaining nine, known as essential amino acids, must be obtained through diet. Lysine is found in dairy products like milk, cheese and yogurt; meat; beans; brewer’s yeast; and wheat germ. Supplements are also widely available. Although the mechanism by which lysine interferes with the herpes virus is not yet clear, researchers believe that it somehow short-circuits the reactivation functions of the virus.

Side effects can include stomach upset, abdominal pain, nausea and diarrhea. Lysine can increase how much calcium the body absorbs, so taking lysine along with calcium supplements requires caution. Although rare, lysine has been tied to reports of certain kidney problems. The safety of taking lysine while pregnant or breastfeeding is not known. If you decide to try lysine, please check with your family doctor for recommended dosages.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Our sons are ages 9, 11 and 14, and like all of the other schoolkids we know, they’re hauling around crazy-huge backpacks all day. What does that weight do to a child’s back? Can carrying a heavy backpack every day cause scoliosis?

Dear Reader: We hear from a lot of parents about the hefty load children carry around while they’re at school.

By the time kids stow all of the textbooks, notebooks, laptops, tablets, binders, snacks, water and miscellaneous school supplies they’ll need during a typical day, these packs can easily tip the scales at 10 pounds -- and frequently much more. Considering that the current recommendation is that a child’s backpack shouldn’t exceed 10 percent of his or her body weight, the plain truth is that our kids are spending their weekdays yoked to considerably more weight than is good for them.

When it comes to scoliosis, a condition in which the spine grows with an abnormal sideways curve, there is no evidence that carrying a heavy backpack will cause it. But plenty of kids with overloaded backpacks do wind up paying a physical price. All of that weight forces them to hunch, slump, tilt or even stagger as they walk, which can stress, torque or compress the spine, neck and shoulders. This can result in aches, pain and muscle strain. Over the long term, the adjustments and contortions needed to repeatedly lift and lug around a hefty backpack during the school day can lead to nerve damage, which reveals itself in tingling, numbness or pins-and-needles sensations.

A study published in 2016 in the Spine Journal found that more than 60 percent of the 5,300 students surveyed suffered from backpack-related pain. And while much importance is placed on the weight of a pack, the study found that how long a pack is carried each day also had a bearing on pain and injury.

Left to their own devices, kids will often choose a backpack for its color, shape or design. That’s when we parents have to step in. Ergonomics aren’t nearly the draw that a cool logo or graphic can be, but they can save your child pain and injury. When shopping for a backpack:

-- Select the proper size. Your child’s backpack should be no wider and no longer than his or her torso. Make sure the pack doesn’t reach more than just a few inches below the waist.

-- Get a pack with wide, padded shoulder straps that are easily adjustable. A padded back panel adds to comfort, too.

-- Just as with backpacks that are used in hiking and camping, chest and hip belts in school packs can help to equalize and stabilize the load.

-- Instead of a pack with a single central pocket, look into those with multiple compartments. Not only can that help with organization, but it makes it easier to evenly distribute the weight.

-- Help your kids evaluate his or her gear and work to lighten the daily load.

To catch potential problems as quickly as possible, let your kids know that when it comes to backpack-related aches or pains, you always want to know the details ASAP.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I was a huge Luke Perry fan in high school, and like so many others, I was shocked that he had a stroke at just 52 years old. Isn’t that awfully young? How do you know if you’re having a stroke?

Dear Reader: While it’s true that the majority of strokes occur in people 65 and older, they can happen in people of any age. This includes not only young and middle-aged adults, but also children and even infants in utero.

Stroke is the fifth-leading cause of death in the United States. Risk factors include high blood pressure, high cholesterol, smoking, obesity and diabetes. Of the 795,000 people each year who have a stroke, 140,000 do not survive. A significant percentage of those who do survive are left with a range of disabilities that affect speech, movement and cognition. One of the challenges for younger stroke victims is misdiagnosis. Symptoms can be mistaken for conditions like migraine, seizure and inner ear disorders.

A stroke occurs when the blood supply to the brain is interrupted, which happens in two ways. The most common type of stroke, known as an ischemic stroke, occurs when blood is unable to travel through a blood vessel and reach the brain. This can be due to a clot that arises in or travels to the brain and blocks the vessel, or to narrowing of the blood vessel itself. In a hemorrhagic stroke, the second major type of stroke, the blood vessel tears or ruptures. In both types of stroke, the result is the same -- the oxygen and nutrients carried by the blood can’t reach the brain cells. In a very short period of time, the brain cells begin to die.

A third type of stroke is known as a transient ischemic attack, or TIA. This is when stroke symptoms appear for a brief period of time but then go away. These so-called "mini strokes" can sometimes be precursors to a major stroke, so it’s important to take TIAs seriously and seek medical treatment immediately.

Signs of stroke include sudden weakness or numbness in a limb or in the face, often on just one side of the body. Sudden dizziness, confusion, garbled speech, loss of balance or coordination, or problems with eyesight in one or both eyes can also signal a stroke. So can the advent of a sudden headache, often quite severe, sometimes accompanied by tingling sensations in the face or body.

A useful memory prompt for stroke symptoms is the word FAST. The letters represent three major indicators of stroke. F is for face drooping, A is for arm weakness and S is for speech. The final letter, T, stands for “time to call 911.” That’s particularly important because swift treatment can be the difference between life and death. It can also affect the level of disability that the stroke causes in a survivor. Studies show that receiving emergency medical care within three hours of the first symptoms of stroke results in less disability three months later as compared to those for whom medical care was delayed. So no matter someone’s age, when symptoms suggest a stroke, seek immediate medical help.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)