Cold or Allergy: How to Tell the Difference

Spring is officially here, with warmer days, gentle breezes, and, of course, little kid sneezes. Your first thought when you hear your kid sneeze or sniffle may be: Is it a cold or allergies? As a parent, it can be difficult to tell the difference between the two.

Fortunately, pediatrician Soniya Mehra, MD, MPH, of Stanford Medicine Children’s Health is here to explain some key differences that can help you determine whether your child is suffering from a cold or allergies.

Dr. Mehra explained that allergies are quite common: Over 50 million Americans are affected, and they can pop up at any age, so they are something to watch for, even in young children.

Although both conditions can cause similar symptoms, such as a runny nose, coughing, and sneezing, Dr. Mehra explained, the key difference between the two ailments is the cause.

“Everything is blooming and turning bright green in our area right now, so you could potentially see an overlap in symptoms. Especially this time of year with the change of weather,” she said. “However, colds are caused by infections, usually viruses, whereas allergies are the body’s response to allergens in the environment. Those can be seasonal or occur year-round. Common allergens are things like pollen, dust mites, pet dander, and mold.”

The type of ailment becomes especially important for school-aged children because it’s vital to know if your child can attend class or if they are contagious and need to stay home.

“The really, really big difference between cold and allergies is that because a cold is caused by an infection, it is infectious or contagious, and allergies are not,” Dr. Mehra said. “So, when a child has their allergies under control, they can attend school because they are not contagious. Whereas a child with a cold will have to follow the school’s policy for being fever-free before they can return to school.”

Since colds and allergies share many of the same symptoms, it may be hard to distinguish between the two, but there are a few differences that may help you figure out the best way to treat your child.

“Both colds and allergies can present with sneezing, runny/stuffy nose, cough, and decreased energy levels. But most colds will have fever and possibly body aches. So, that’s a big difference,” Dr. Mehra said. “On the other side, allergies cause an itchy sensation that can occur in our eyes, ears, nose, and throat. When you feel that classic itchiness, it’s pointing toward allergies.”

The time when your child starts to show symptoms, and their duration, offer more clues as to whether it’s a cold or allergy. According to Dr. Mehra, allergy symptoms can start immediately after being exposed to an allergen. So, if your child has a runny nose soon after petting the neighbor’s dog, allergies are a likely culprit. Allergies can also last a long time, even year-round, without treatment.

“If you are seeing your child really rub their eyes and try to clear their throat all the time, or if it’s something that is not going away for weeks, but they’re still playful and eating, then I’d really suspect that allergies are the problem,” she said.

On the other hand, Dr. Mehra said, colds can incubate for a few days before your child starts to show symptoms. If your child went to a party on Friday and was exposed to a cold virus, they may not show symptoms until Monday. Colds usually last about three to seven days, so if your child starts feeling better after a week, it was probably just a cold.

If you’re still wondering about the cause of your child’s illness, Dr. Mehra suggests consulting a health care professional.

“There’s no bad reason to come in to see your pediatrician,” she said. “We have things that we look for during the physical exam with our tools like the otoscope. So, we can see signs internally that correlate between a cold versus allergies.”

To learn more about colds and childhood allergies, check out “Allergies in Children,” “Protecting Your Kids From Colds and Flu,” and “When to See a Doctor for a Sore Throat.”