As spring pollen counts increase to a maximum these days, I once again hear parents' concerns that their child is experiencing "thick green mucus." Often, it's specifically the color change of the mucus that spurs them to make an appointment. Parents may identify changes in the color and viscosity of mucus as a sign of a worsening illness or sinusitis. However, the color and consistency of one's nasal discharge is almost completely meaningless.
This myth seems to have persisted over the decades and its origins are likely in the early days of modern medicine, when many common processes were not yet understood. mucus, a lubricant and moisturizer, helps keep our nasal passages healthy by trapping dirt and preventing over drying. It may be gross, but it's necessary and helpful. We experience higher mucus productions when our bodies are under attack from viruses, bacteria, or pollen. Our immune system responds to these attacks by dilating blood vessels and allowing white blood cells to transfer from the blood into the mucus.
When the mucus is filled with these cells, it changes both color and consistency. Depending on the amount of white cells and other factors such as hydration, its color changes. It can be clear, yellow or green and it can be thick or runny. These changes can be caused by viruses, bacteria, pollen or other irritants, so the changes are not helpful in figuring out what the root cause is. They also do not mean the child is getting sicker.
There are two exceptions to this: frank pus and blood tinged mucus. "Frank pus" is the medical term for pure white pus coming out of one's nose. This could be a sign of a more serious infection. Bloody noses are extremely common in children and are generally not concerning. But if mucus is always speckled with blood, it's a good idea to run it by your pediatrician.
One of the most important things to understand is that a change in mucus color does not mean the child needs antibiotics. Antibiotics would only be required in the event that a true bacterial infection has been diagnosed. Antibiotics do absolutely nothing for viruses and allergies. A diagnosis of a bacterial infection can only be made by your pediatrician and is based on several criteria, none of which involve mucus color unless it is purely pus.