The pediatric resident I was overseeing in our busy sick clinic at St. Christopher's Hospital for Children hurriedly described the 2-year-old he had just seen with a rash on his trunk.

"I think the child's been beaten," the resident said to me, wide-eyed and somewhat shaken. "He has several long, dark lines on his back and stomach. It looks like slap marks."

Child abuse and neglect is the dark side of pediatrics that is seen all too often. There are telltale signs, "red flags" that alert pediatricians to the possibility a child has been intentionally abused: bruising in a child who isn't yet crawling; marks on areas where there are no bony prominences, such as the ears, neck, and, like our patient, the trunk.

In 2013, ChildLine, Pennsylvania's child-abuse hotline, registered 26,944 reports of suspected abuse or neglect; an increase of 280 from the previous year. Pennsylvania received more reports of suspected child and student abuse in 2013, the most recent year for which we have data, than any other year on record. Pediatricians must always be diligent.

"How did the family act?" I asked the resident. "Concerned," he said.

"What did they say caused the marks?"

"They weren't sure," he said, "but it looks suspicious. I think we need to report it," he said confidently.

I had another question, however.

"Have they been in the sun recently?"

"I didn't ask," the puzzled resident replied.

"Ask," I insisted.

Solution

Kids are always getting rashes in the summer. Poison ivy and oak. Sunburns. Allergic reactions to sunlight including solar urticaria (hives) and polymorphous light reactions. Insect bites. Lyme disease's infamous "target lesion."

And then there is phytophotodermatitis - plant-induced photosensitivity. Basically, sunlight hits the skin of a child who also has been exposed to certain plants, and there is a reaction.

The most common troublemakers are furocoumarin chemicals found in some vegetables, fruits, and weeds. In susceptible individuals, sunlight can hit the chemical on the skin, heating it up and causing blistering, redness, and areas of darker pigment where the reaction occurred.

Could this have been the case in our patient?

It turned out the child and his family had been at Disney World and enjoyed soaking up the sun.

"Did you drink lemonade?" the resident asked.

"We made our own with locally squeezed lemons. The kids loved it," the child's father said.

With this new information, I went to the child's room. The rash, I saw right away, was in the exact shape of a man's large hands, and was placed right where a dad would grasp his child to lift him up.

But because this dad had been squeezing lemons, a source of furocoumarins, the Florida sun turned the celebration into a rash.

I asked the resident how he would now handle such a case in the future.

"Advise about washing hands after touching lemons," he answered.

Daniel R. Taylor, D.O., is an associate professor at Drexel University College of Medicine and director of community pediatrics and child advocacy at St. Christopher's Hospital for Children.