- What Are They?
- Are They Contagious?
- Incubation Period
- Contagious Period
What is a cold? What is a sinus infection (sinusitis)?
A cold is a common viral infection of the nose and throat that causes inflammation, runny nose, sneezing, and a sore throat. Some people also develop a fever. Cold symptoms typically last about 7-11 days. Rhinoviruses are the most common of about 200 types of cold viruses.
In contrast, although viruses cause most sinus infections, a few (5%-10%) are complicated by bacterial or rarely fungal infections. Infection of the paranasal sinuses and the nasal mucosa causes facial pain about 10 days after the onset of upper respiratory symptoms (similar to cold symptoms) and may last about 2-12 weeks (acute lasts about 2-4 weeks while subacute lasts about 4-12 weeks), with chronic sinusitis lasting 12 weeks or longer. Thus, the duration of a sinus infection is much longer than a cold.
What are the causes and risk factors for colds and sinus infections?
Viral infections are the most common cause for both colds and sinus infections. Risk factors that can increase the chances of sinus infections include the common cold, allergies, allergic rhinitis, nasal polyps, or a deviated septum; these may cause sinus blockage (inability to drain fluids from sinuses due to swollen sinuses and/or blockage with mucus and cell debris).
Are colds and sinus infections contagious?
Colds are very contagious and spread by direct contact and/or infected droplets spewed when coughing or sneezing. A sinus infection caused by a virus is considered contagious, but most researchers do not consider bacterial sinus infections contagious because they usually do not spread to other individuals.
What are the incubation periods for colds and sinus infections?
The incubation period for colds ranges from about 24-72 hours, while the incubation period for sinus infections is about 7-11 days after cold-like symptoms develop.
What are the contagious periods for colds and sinus infections?
Sinus infections (note that only viral-caused sinus infections are contagious) shed contagious viruses for about a week before signs and symptoms of a sinus infection develop and may remain mildly contagious for weeks. Colds are highly contagious. Individuals become contagious about a day before symptoms develop and remain contagious for about 5-7 more days.
How do signs and symptoms of a cold differ from those of a sinus infection?
In the first few days of both diseases, symptoms and signs may be essentially the same and can include some or most of the following:
- Nasal irritation or dryness
- Sore throat
- Stuffy nose
- Nasal discharge/congestion
- Other less frequent symptoms like
For colds, symptoms maximize in about 2-3 days and usually resolve in 7-11 days. For sinus infections, however, symptoms do not resolve after 7-11 days and additional symptoms occur, such as:
- Sinus pressure behind the eyes or cheeks (sinus pain or facial pain)
- Facial pain when pressure is applied to the frontal sinus
- Thick green or yellow mucus production
- A blocked nose (sinus drainage area and nasal passages are clogged with mucus and cell debris)
- Redness of nose, cheeks, and/or eyelids
- Persistent coughing
- Bad breath
What tests do doctors use to tell a cold from a sinus infection?
Because the common cold is self-limiting and so many viral types can cause colds, doctors seldom use any tests to diagnose the disease. However, doctors may differentiate between the common cold and sinus infections by the patient history (duration of symptoms less than 10-14 days is unlikely a sinus infection). Sinus X-rays and/or CT of the sinuses may be useful to help diagnose sinus blockage, and bacterial testing may reveal a bacterial cause (rare) or a bacterial coinfection of the sinus infection.
What are medications and treatments for colds and sinus infections?
Treatment for colds is focused on relief of symptoms and preventing spread. Treatments include rest, hydration fluids, antihistamines like Benadryl or Claritin, nasal decongestants like phenylephrine, anticholinergics like Atrovent, NSAIDs like Aleve and Tylenol, Robitussin, possibly vitamin C, and zinc (decreases symptoms in adults). Antibiotics are not necessary unless bacterial coinfection develops. These medications may also treat sinus infection symptoms. However, in addition, people may use topical intranasal steroids, nasal sinus irrigation, mucus thinners, and antibiotics. Some individuals may require sinus puncture or surgery to remove thick secretions, obtain bacterial cultures, and provide surgical drainage and/or to remove obstructions to sinus drainage.
How does the prognosis and duration of a cold differ from that of a sinus infection?
The prognosis is usually excellent for self-limiting colds although they often may reoccur. Their duration is about 7-11 days. The prognosis of sinus infections may range from good to fair depending on how the infection progresses and/or responds to treatments. Although some acute sinus infections can even be self-limiting (about 40%), their duration is about 2-4 weeks, while subacute infections last about 4-12 weeks and chronic sinus infections last 12 weeks or more.
Is it possible to prevent colds and sinus infections?
Because both colds and many sinus infections start with a viral infection, avoiding close contact with individuals who are infected may reduce the risk of infections. Unfortunately, there are no vaccines against colds or sinus infections. A good diet, exercise, enough sleep, good hand washing hygiene, and reducing stress are ways to help your immune system function well and decrease the risk of viral infections. Avoid smoking, nasal irritants, and alcohol consumption. If you have a partial blockage of sinus drainage (for example, polyps or deviated septum), consider having a doctor treat it.
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Brook, I. "Acute Sinusitis." Medscape. March 1, 2018. <https://emedicine.medscape.com/article/232670-overview>.