There are a couple reasons colds worsen.

Sometimes, it’s due to your anatomy.

Do you have a sinus obstruction?

Then, it’s easy to progress to a sinus infection.

Do you have an underlying medical condition, such as asthma?

There’s a good chance you’ll get sicker.

How can you thwart developing complications.

Treat that cold quickly.

As soon as you get symptomatic, practice good handwashing techniques, proper nutrition and get lots of sleep.

You can treat your symptoms with medication for further comfort.