Cold vs. Sinus Infection: How to Tell the Difference

How does a cold normally behave?

A cold (viral upper respiratory infection) follows a recognizable arc. It typically begins with a scratchy throat, runny nose, and sneezing. Over days two through four symptoms peak — congestion, thick discharge, cough, and sometimes mild fatigue or a low-grade fever. Nasal discharge can turn yellow or green during a cold; this is a normal immune response and does not automatically mean bacterial infection. By days seven to ten, most people are clearly improving even if a lingering cough remains. Colds are caused by viruses, most often rhinovirus, and antibiotics do not help them.

What patterns suggest bacterial sinusitis?

Acute bacterial rhinosinusitis becomes more likely in three specific clinical scenarios identified in IDSA clinical practice guidelines 1Ref 1Chow AW, Benninger MS, Brook I, et al. (2012).IDSA Clinical Practice Guideline for Acute Bacterial Rhinosinusitis in Children and Adults.Three diagnostic criteria for acute bacterial rhinosinusitis (10-day persistence, double worsening, severe onset); amoxicillin-clavulanate as first-line therapy; mucus color unreliability; watch-and-wait approach for mild cases:

• No improvement after ten days. Persistent nasal discharge, facial congestion, or postnasal drip that has not clearly peaked or started improving by day ten.
• Double worsening (double sickening). You were getting better, then around days five to seven you suddenly felt noticeably worse again — new or worsening fever, increased facial pressure, and more discolored discharge.
• Severe illness from the start. High fever (above 39°C / 102°F), significant facial pain, and discolored discharge all present together at the very onset of illness.

Any of these patterns should prompt a call or visit to a clinician. Bacterial sinusitis is much less common than viral sinusitis — most people with sinus symptoms have a cold 1Ref 1Chow AW, Benninger MS, Brook I, et al. (2012).IDSA Clinical Practice Guideline for Acute Bacterial Rhinosinusitis in Children and Adults.Three diagnostic criteria for acute bacterial rhinosinusitis (10-day persistence, double worsening, severe onset); amoxicillin-clavulanate as first-line therapy; mucus color unreliability; watch-and-wait approach for mild cases.

Why is mucus color an unreliable guide?

Many people assume yellow or green mucus means a bacterial infection that needs antibiotics. In reality, that color comes from immune cells (neutrophils) and is a normal part of both viral and bacterial inflammation. Clear mucus can be present in bacterial infection; green mucus is common in a straightforward cold. Clinicians rely on the time course and symptom pattern — not discharge color — to make this distinction 1Ref 1Chow AW, Benninger MS, Brook I, et al. (2012).IDSA Clinical Practice Guideline for Acute Bacterial Rhinosinusitis in Children and Adults.Three diagnostic criteria for acute bacterial rhinosinusitis (10-day persistence, double worsening, severe onset); amoxicillin-clavulanate as first-line therapy; mucus color unreliability; watch-and-wait approach for mild cases.

What happens at a clinician visit?

A clinician will ask about your symptom timeline, examine your nose and throat, palpate your sinuses, and check for fever. This exam is usually enough to make a clinical judgment. Imaging (CT or X-ray) is rarely needed for acute sinusitis and is not routine 1Ref 1Chow AW, Benninger MS, Brook I, et al. (2012).IDSA Clinical Practice Guideline for Acute Bacterial Rhinosinusitis in Children and Adults.Three diagnostic criteria for acute bacterial rhinosinusitis (10-day persistence, double worsening, severe onset); amoxicillin-clavulanate as first-line therapy; mucus color unreliability; watch-and-wait approach for mild cases. If bacterial infection seems likely, a short antibiotic course may be prescribed — amoxicillin-clavulanate is the standard first-line choice in most guidelines. If symptoms are mild and the timeline is borderline, a watch-and-wait approach — holding antibiotics and reassessing in a few days — is often recommended for adults, because many cases resolve without treatment 1Ref 1Chow AW, Benninger MS, Brook I, et al. (2012).IDSA Clinical Practice Guideline for Acute Bacterial Rhinosinusitis in Children and Adults.Three diagnostic criteria for acute bacterial rhinosinusitis (10-day persistence, double worsening, severe onset); amoxicillin-clavulanate as first-line therapy; mucus color unreliability; watch-and-wait approach for mild cases.

Supportive care while you wait and watch

Whether your symptoms turn out to be viral or bacterial, these measures help:

• Saline nasal rinses help clear secretions and rinse out inflammatory mediators
• Nasal corticosteroid sprays can reduce mucosal inflammation (most useful for allergic or recurring sinusitis)
• Over-the-counter pain relievers (ibuprofen or acetaminophen) for facial pain and fever
• Staying well hydrated helps thin mucus
• Steam inhalation provides temporary relief for congestion

Oral decongestants (pseudoephedrine) can help with stuffiness but are not recommended for people with high blood pressure or heart conditions.

What else could cause these symptoms?

Viral upper respiratory infection (most likely). Symptoms peaked around days three to five and are trending better; mild or no fever; others nearby are also sick.

Allergic rhinitis. No sore throat at onset; itchy eyes; symptoms track with pollen season or outdoor exposure and recur annually.

Dental infection. Upper molar infections can spread into the adjacent maxillary sinuses, causing sinusitis that does not respond to standard antibiotics — dental care is also required 2Ref 2Centers for Disease Control and Prevention (2024).Sinus Infection Basics.Viral etiology of most sinus infections; antibiotics not needed for most cases; distinguishing viral from bacterial presentations; dental infections as a cause of sinusitis.