Viral Upper Respiratory Infection

What are the typical early symptoms of an upper respiratory tract infection and how does it progress?

Sore throat, runny nose, and feeling rundown are the most common initial symptoms. Fever, if present, typically occurs during the first few days. Nasal congestion and cough usually come on the second or third day. Many infections improve after seven to ten days. However, some, such as influenza, can have a longer course.

Medically, what makes you worry that this is something that needs more treatment or attention?

Here, the clinician’s mind is usually trying to determine three things: First, is this viral or could it be bacterial? Second, if this is bacterial, does this person need antibiotics to kick it? Third, what are the best supportive therapies for this individual, regardless of viral versus bacterial, based on their symptoms and treatment preferences?  

How do you determine whether the cause is bacterial?

After ten days, about 60% of sinus infections can be considered bacterial. If someone presents with ten days of facial pressure and thick nasal discharge, we’ll consider using antibiotics, though most of those infections would self-resolve even if not treated.  

Fever greater than 102 F for more than two or three days may suggest a bacterial cause (although some viruses such as the flu can have fevers that last five-to-seven days). Persistent sore throat or the inability to swallow can indicate a more severe throat infection that may need prompt medical intervention.

Bronchitis (a chest cold) is almost always viral, but if it’s associated with shortness of breath, night sweats, or high fevers, we start to get concerned about pneumonia, which should be treated with antibiotics. (Additionally, we keep a closer eye on less resilient individuals, including older people and those with compromised immune systems.)

Can you explain how clinicians think about “double worsening” and the trajectory of illness for people with ongoing symptoms?

“Double worsening” refers to a pattern of initial improvement followed by worsening between days five and ten. That’s suggestive of a bacterial cause.

As for ongoing  symptoms, nasal discharge and coughs last the longest. It’s not uncommon for these to linger for several weeks with a viral infection.

Is there evidence for facial tenderness or tooth pain being bacterial versus viral? Any other specific symptoms to pay attention to?

For head colds, facial tenderness or pain radiating to the teeth can occur with both viral and bacterial infections.

As for other symptoms, duration beyond seven-to-ten days, severity, and “double-worsening” are the most important factors in diagnosis. The doctor’s job is to help consider all factors and timelines together to assess clinical likelihood and make real time decisions.  

Can you unpack some of the myths around yellow/green snot and anything else you hear commonly that might mislead people about accurate diagnosis?

Most people assume that snot color carries valuable clinical information. But in truth, it isn’t very telling. Thickness of snot can be helpful, but it still isn’t a great indicator of bacterial versus viral infections.

The duration of a cough is not as big of a determinant as most people suspect, and usually reflects drainage of mucus from the head into the chest. In fact, we expect most coughs to last two-to-three weeks in this context.