If you have a young child, you’re probably no stranger to runny noses. If you've ever wondered whether yellow mucus means your child needs antibiotics or whether a runny nose is a sign they're getting sick, you're not alone. Many parents have questions about what different types of snot can mean. But your child’s snot color alone usually does not tell the whole story. Children’s Hospital Colorado’s pediatrician Christopher Stille, MD, MPH, shares why snot happens, what different colors of snot can mean and when to check in with your child’s doctor.

Why do kids have snot?

Snot is a type of mucus produced inside your nose and sinuses that has an important job. When you breathe in, mucus helps trap dust, dirt, allergens, viruses and bacteria in the air before they can travel deeper into the lungs. Everyone has mucus in their nose, even when they’re healthy. It’s your body’s way of keeping your airways clean and protecting your respiratory system.

Does yellow or green mucus mean an infection?

It can be concerning when your child’s snot changes color. When your child has yellow snot or green snot, it contains white blood cells, which are part of the body’s immune system. This happens when the body notices something it may need to fight off, such as a viral infection or bacterial infection. This does not automatically mean your child needs antibiotics. Viral infections get better without antibiotics, and the vast majority of upper respiratory illnesses are caused by viruses.

What do other snot colors mean?

Snot can also look darker or more colorful when it dries out.

Brown mucus or black mucus: Brown snot or black snot can happen after exposure to dirt, dust or other debris.

Red mucus or pink mucus: Red snot or pink snot often means the lining of the nose is irritated and a small amount of blood has mixed in, which can happen because the nose has tiny blood vessels close to the surface.

Is clear snot a sign that my child is not sick?

No, clear mucus can still show up when your child is coming down with a cold, especially at the beginning. Many common colds start with clear nasal drainage and then become cloudy, yellow or green for a few days before improving.

Clear, watery nasal drainage is also common with seasonal allergies. Your child is more likely to have allergies rather than a cold if their symptoms include sneezing, an itchy nose or itchy eyes, and occur around triggers such as pollen, pets or dust.

Can the color of my child’s snot tell me exactly what’s wrong?

No, the color of the snot alone can’t tell you what’s going on, but it can provide some clues. Instead of focusing on color alone, look at the bigger picture:

• How long has your child been sick?
• What other symptoms do they have, such as fever, pain, low energy or a cough?
• Are symptoms getting better or worse?

What can I do at home to help my child with a stuffy nose?

A stuffy nose can be frustrating for both kids and parents, especially when it makes it harder to eat, sleep or play. The goal is to keep your child comfortable and hydrated. Here are some ways to help relieve a snotty nose at home:

• Saline spray: This can help keep nasal passages moist, which may make mucus easier to clear and breathing more comfortable — especially in Colorado’s dry climate. You can use saline spray when your child is sick or anytime their nose feels dry.
• Steamy shower: Run a hot shower for a few minutes, then sit with your child in the warm, steamy bathroom and let them breathe in the moist air. The added moisture can help loosen mucus and make a stuffy nose feel less congested.
• Nasal suction device: A gentle suction device can work well for babies and young children who cannot clear their noses well on their own. They can be especially helpful for infants, because babies younger than 4 months are not very good at breathing through their mouths yet.

Use caution with nasal rinses, especially machines, for young children. If you are considering a rinse device, ask your child’s doctor what is safe and appropriate for your child’s age and needs.

When should I call the doctor?

It can be hard to know when a runny or stuffy nose is just part of a common cold and when it might be something more. If you're concerned about your child's symptoms, it's always OK to reach out to your pediatrician. Call your child’s doctor if the symptoms last longer than a week, start to get worse or seem to improve and then come back, or come with a fever over 100.4 that lasts more than 5 days. If your child has a fever and is acting very sick such as not able to wake up, call right away. Your pediatrician can help you determine if your child might have an ear infection, sinus infection or something else that might need treatment.

While snot color alone can’t give you a clear answer of what’s causing your child’s symptoms, it can offer helpful clues. The most important thing is to look at the bigger picture, including how long symptoms have lasted, whether they're getting better or worse, and how your child is feeling overall. When in doubt, your child's pediatrician can help you understand what's normal, what might need treatment and when to seek additional care.