Your frequent questions answered by the experts at Nationwide Children's Hospital

My 8-year-old son enjoys sledding but I'm worried about the dangers and how to protect him.For instance, should he be wearing a helmet?

Sledding is a classic recreational winter pastime. It's exciting, easy and inexpensive. But sledding injuries also send more than 20,000 children and adolescents to emergency departments each year.

A study conducted by the Center for Injury Research and Policy of The Research Institute at Nationwide Children's Hospital found the most common injuries were fractures, followed by cuts and bruises. The head was the most commonly injured body part and traumatic brain injuries constituted 9 percent of cases. To reduce the risk of head injuries, children should always wear a helmet.

Sledders should keep their arms and legs within the sled at all times and always sit face-forward, feet-first. Go down the hill one at a time with only one person per sled (except for adults with young children).

Be sure to select a hill that is not too steep and has a long flat area at the bottom to safely glide to a stop. Avoid hills near streets, parking lots, ponds, trees, fences or other hazards. Finally, icy hills make for hard landings if sledders do fall, so be sure to pick snowy hills.

What is seasonal affective disorder? I'm starting to suspect that my 12-year-old might have it, but I'm not sure if it's that or something else that's getting her down this winter.

Seasonal affective disorder (SAD) refers to a type of depression that tends to recur at the same time each year, usually during the winter months and as the days get shorter.

The most important question here is whether your daughter is experiencing an episode of depressed mood and suffering from a depressive disorder. The symptoms of SAD can range from mild to severe and may include irritability, feeling sad, decreased enjoyment, fatigue or low energy, changes in appetite or weight, poor concentration, sleep problems, and thoughts of death or suicide.

Depressive disorders, whether seasonal or otherwise, are quite common in children and adolescents.Approximately one in five adolescents experiences a major depressive episode by the time they are 18. Many who suffer from depression any time of year may also find that their mood deteriorates in the winter months.

Evaluation by a primary care physician makes the most sense, but evaluation by a mental health professional may also be beneficial.

The good news is there are effective treatments available for children and adolescents. Specific types of psychotherapy have proven to be effective, as have certain antidepressant medications.

I'm confused about the differences between an urgent care and the emergency department. When should I take my child to an urgent care and what services are provided there?

Urgent care locations offer treatment for illnesses and injuries that need immediate attention but are not serious enough to warrant a trip to the emergency department. Treatment for the following is provided: minor cuts and burns, possible broken bones/simple fractures (facility will perform X-rays and initial treatment), sprains, strains, vomiting, diarrhea, asthma (mild or moderate wheezing), rashes, mild allergic reactions and fever.

Go to the emergency department if your child's problem is a true emergency, or for treatment of major trauma/injuries, injuries involving a motor vehicle, a fall from a height, serious head injury with loss of consciousness, changes in normal behavior, or vomiting, serious or large burns, obvious broken bone in the leg or arm, severe difficulty breathing, fever in infants 8 weeks of age or less, severe pain and seizures.

In a serious or life-threatening medical emergency, always call 911. In situations where calling 911 isn't necessary, call your family doctor first to determine the best treatment option.