Nasal congestion has many causes including allergies and infection, and can range from a mild annoyance to a life-threatening condition. The newborn infant prefers to breathe through the nose (historically referred to as "obligate nasal breathers").^[2] Nasal congestion in an infant in the first few months of life can interfere with breastfeeding and cause life-threatening respiratory distress. Nasal congestion in older children and adolescents is often just an annoyance but can cause other difficulties.

Nasal congestion can interfere with the ears, hearing, and speech development. Significant congestion may interfere with sleep, cause snoring, and can be associated with sleep apnea. In children, nasal congestion from enlarged adenoids has caused chronic sleep apnea with insufficient oxygen levels and hypoxia, as well as right-sided heart failure. The problem usually resolves after surgery to remove the adenoids and tonsils.

Nasal congestion can also cause mild facial and head pain, and a degree of discomfort.