The viral infection may spread to:

• The sinuses
• The middle ear
• The throat
• The lower respiratory tract, causing bronchitis, bronchiolitis or pneumonia

The viral infection may become complicated by a bacterial infection. Then the clear nasal discharge will become purulent (green).

The viral infection may also trigger an asthma attack in children who suffer from asthma.

Viral complications are most common in infants as they have an immature immune system with little resistance to many viruses.