Sinus Infection vs. Allergies: What's the difference?

Sinus infections are marked by nasal congestion, pressure and headaches.
Sinus infections are marked by nasal congestion, pressure and headaches.

Both sinus infections and allergies (allergic rhinitis) cause symptoms such as runny or stuffy nose and fatigue.

Sinus infection (known as sinusitis) is inflammation of the sinuses, caused by infection from bacteria, viruses, and/or fungi (molds). A sinus infection that lasts three to eight weeks is considered acute. Sinus infections lasting longer than eight weeks are considered chronic. A sinus infection is often contagious and may be mistaken for the common cold. When sinus infections are caused by bacteria, an antibiotic treatment may be prescribed.

Signs and symptoms of sinus infection include runny or stuffy nose, greenish nasal discharge, cough, postnasal drip, tenderness of the face under the eyes or at the bridge of the nose, sinus headache, fever, tooth pain, fatigue, and bad breath. Home remedies for sinus infections are aimed at reliving symptoms and include staying hydrated, using a steam vaporizer, taking over-the-counter (OTC) sinus or pain medications, and nasal irrigation with devices such as a Neti pot.

Allergic rhinitis occurs when certain allergies cause nasal symptoms. When a person with allergies breathes in an allergen, such as pollen, dust, or animal dander, symptoms such as runny or stuffy nose, itching, sneezing, and fatigue occur. Allergic rhinitis that is a result of allergic reactions to plant pollens is commonly called hay fever or seasonal allergies. Limiting exposure to allergy triggers can help reduce allergy symptoms.

What causes sinus infections vs. allergies?

Sinus Infection

Sinus infections or sinusitis may be caused by anything that interferes with airflow into the sinuses and the drainage of mucus out of the sinuses. The sinus openings (ostea) may be blocked by swelling of the tissue lining and adjacent nasal passage tissue, for example with

  • common colds,
  • allergies, and
  • tissue irritants such as OTC nasal sprays, cocaine, and cigarette smoke.
  • Other causes of sinus infections or sinusitis
  • Tumors or growths also can block the sinuses if they are near the sinus openings.

Dehydration, disease, drying medications, and lack of sufficient humidity can cause sinusitis or sinus infection.The drainage of mucous from the sinuses can also be impaired by thickening of the mucous secretions, by decrease in hydration (water content) of the mucous brought on by disease (for example, cystic fibrosis), drying medications (antihistamines), and lack of sufficient humidity in the air. The epithelial cells have small hair-like fibers, called cilia, which move back and forth to help the mucus move out of the sinuses. These small cilia may be damaged by many irritants, especially smoke. This can prevent them from assisting the mucus in draining from the sinuses, and thus results in sinus infections or sinusitis.

Stagnated mucus provides an environment for bacteria, viruses and in some circumstances, (for example, AIDS or immunodepressed people) fungus, to grow within the sinus cavities. In addition, the microbes themselves can initiate and exacerbate sinus blockage. The most commonly infected sinuses are the maxillary and ethmoid sinuses.

Rarely, immunodepressed or victims of multiple traumas in disasters such as tsunamis, hurricanes, earthquakes, or tornadoes may breathe in fungi from the soil or water. Eventually, in a few days to over a week, the fungi can grow and cut off blood supply to almost any type of tissue, especially in the nose and eyes. These infections, although rare, are serious and can be deadly and require immediate medical and surgical care. Although the fungal infection may resemble common bacterial sinusitis initially, it is a disease termed zygomycosis or mucormycosis.

Allergies

Because allergic rhinitis is frequently caused by pollen, symptoms occur when pollen is in the air. Trees primarily pollinate in the spring, while grasses pollinate in the spring and summer. Weeds usually pollinate in the late summer and fall. Of allergy sufferers in the United States, many are allergic to ragweed, about half are allergic to grasses, and fewer are allergic to trees. Of course, many people are allergic to other substances such as mold spores, animal dander protein, and dust mites, to name a few.

An allergic reaction occurs when the immune system attacks a usually harmless substance called an allergen (as outlined above) that gains access to the body. The immune system calls upon a protective substance called immunoglobulin E (IgE) antibodies to fight these invading allergic substances or allergens. Even though everyone has some IgE, an allergic person has an unusually large amount of IgE. This army of IgE antibodies attacks and engages the invading army of allergic substances of allergens.

Specialized cells called mast cells also participate in the allergic reaction. Mast cells release a variety of chemicals into the tissues and blood, one of which is known as histamine. These chemicals frequently cause allergic reactions. These chemicals are very irritating and cause itching, swelling, and fluid leaking from cells. Through various mechanisms, these allergic chemicals can cause muscle spasm and can lead to lung and throat tightening as is found in asthma and loss of voice (laryngitis).

QUESTION

Allergies can best be described as: See Answer

What are the symptoms and signs of sinus infections and allergies?

Sinus infection

There are many signs and symptoms of sinusitis and sinus infections. The following is a summary of predominant ones (18 total) that may occur. Most patients have several signs and symptoms at the same time. Others may have some symptoms that are intermittent; most do not have all symptoms at once. The signs and symptoms of a sinus infection or sinusitis include the following:

  • Headache due to pressure in partially or completely blocked sinuses. The pain may increase when the person bends down.
  • Facial tenderness and/or swelling when facial areas over sinus areas are touched.
  • Pressure or pain due to mucus pressing on sinus tissue or inflammation of sinuses.
  • Fever due to inflammation of sinus tissues and infection.
  • A cloudy, discolored nasal drainage is often seen in bacterial sinus infections.
  • Congestion is a feeling of nasal stuffiness, and occurs with both infectious and non-infectious sinusitis.
  • Post nasal drip is mucus overproduction from sinusitis that flows to the throat and irritates throat tissue.
  • Sore throat is inflammation of throat tissue by post nasal drip.
  • Cough is a response to post nasal drip and body's attempt to clear out throat tissue irritants.
  • Tooth pain caused by pressure on surrounding nerves and tissues
  • Ear pain caused by pressure on surrounding nerves and tissues
  • Eye pain caused by pressure on surrounding nerves and tissues
  • Fatigue due to fever, immune response and/or coughing
  • Bad breath usually is due to bacterial infections
  • Itching/sneezing - In noninfectious sinusitis, other associated allergy symptoms of itching eyes and sneezing may be common, but may include some of the symptoms listed above for infectious sinusitis.
  • Nasal drainage usually is clear or whitish-colored in people with noninfectious sinusitis.
  • Ulceration can occur with rare fulminant fungal infections with sharply defined edges and a black, necrotic center in the nasal area. Some fungal infections cause dark, black-appearing exudates. This requires immediate medical evaluation.
  • Multiple chronic (over one to three months) symptoms usually are a sign of subacute or chronic sinusitis

Allergies

Allergic rhinitis is the correct term used to describe the allergic inflammation of the nasal passages. Rhinitis means "inflammation of the nose" and is a derivative of rhino, meaning nose. Allergic rhinitis that occurs during a specific season is called "seasonal allergic rhinitis." When it occurs throughout the year, it is called "perennial allergic rhinitis." Rhinosinusitis is the medical term that refers to inflammation of the nasal lining as well as the lining tissues of the sinuses. This term is sometimes used because the two conditions frequently occur together.

Symptoms of allergic rhinitis, or hay fever, frequently include

Postnasal dripping of clear mucus frequently causes a cough. Loss of the sense of smell is common, and loss of taste sense occurs occasionally. Nose bleeding may occur if the condition is severe. Eye itching, redness, and excess tears in the eyes frequently accompany the nasal symptoms. The eye symptoms are referred to as "allergic conjunctivitis" (inflammation of the whites of the eyes). These allergic symptoms often interfere with one's quality of life and overall health.

Many people with allergies have difficulty with social and physical activities. For example, concentration is often difficult while experiencing allergic rhinitis symptoms.

What is the treatment for sinus infections and allergies?

Sinus Infection

Viral sinusitis

Antibiotics are not necessary for sinusitis caused by a virus. Frequently recommended treatments include pain and fever medications, for example:

Bacterial sinusitis

Bacterial infection of the sinuses is suspected when facial pain, nasal discharge resembling pus, and other symptoms last longer than a week, and are not responding to over-the-counter (OTC) nasal medications.

Acute sinus bacterial infection usually is treated with antibiotics aimed at treating the most common bacteria known to cause sinus infection. It is unusual to get a reliable culture without aspirating the sinuses.

The five most common bacteria causing sinus infections are:

Antibiotic treatment for sinus infections must be able to kill these five types of bacteria.

Amoxicillin (Amoxil) is acceptable for uncomplicated acute sinus infections; however, many doctors prescribe amoxicillin-clavulanate (Augmentin) as the first-line antibiotic to treat  a possible bacterial infection of the sinuses. Amoxicillin usually is effective against most of the strains of bacteria.

Penicillin allergies and treatment for sinusitis

Other antibiotics may be used as a  first choice if you are allergic to penicillin, for example,

If you don't improve after five days of taking the antibiotic, contact your doctor because he may want to switch antibiotics to one of the five listed above or amoxicillin-clavulanate (Augmentin).

Generally, an effective antibiotic needs to be continuously for a minimum of 10-14 days. However, it is not unusual to treat sinus infections for 14-21 days.

Some antibiotics now are thought to reduce inflammation, independent of the anitbacterial activity.

Allergies

Avoidance of identified allergens is the most helpful factor in controlling allergy symptoms. Attempts to control the environment and avoidance measures often significantly aid in resolving symptoms. However, allergy avoidance is often not easy. A thorough discussion with your physician is needed, and control measures may be required daily.

If avoidance is not possible or does not relieve symptoms, additional treatment is needed. Many patients respond to medications that combat the effects of histamine, known as antihistamines. Antihistamines do not stop the formation of histamine, nor do they stop the conflict between the IgE and antigen. Therefore, antihistamines do not stop the allergic reaction but rather protect tissues from the effects of the allergic response.

The first-generation antihistamines, such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), dimenhydrinate (Dramamine), brompheniramine (Dimetapp and others), clemastine fumarate (Tavist, Allerhist), and dexbrompheniramine (Drixoral) frequently cause mouth dryness and sleepiness as side effects.

Newer, so-called "non-sedating" or second-generation antihistamines are also available. These include loratadine (Claritin), fexofenadine (Allegra), cetirizine (Zyrtec), and azelastine (Astelin Nasal Spray). In general, this group of antihistamines is slightly more expensive, has a slower onset of action, is longer acting, and induces less sleepiness. Many of these medications are available over the counter.

Discuss with a physician other antihistamine side effects that occasionally occur (for example, urine retention in males, fast heart rate, and others). Always discuss the potential side effects of any medication with a physician and/or pharmacist.

Decongestants help control allergy symptoms but not their causes. Decongestants shrink the swollen membranes in the nose and make it easier to breathe. Decongestants can be taken orally or by nasal spray. Decongestant nasal sprays should not be used for more than five days without a doctor's advice, and if so, usually only when accompanied by a nasal steroid. Decongestant nasal sprays often cause a so-called "rebound effect" if taken for too long. A rebound effect is the worsening of symptoms when a drug is discontinued. This is a result of a tissue dependence on the medication.

Some people with allergies need specialized prescription medications such as corticosteroids, cromolyn, and ipratropium (Atrovent) nasal sprays. These nasal sprays do not cause the rebound effect noticed with decongestant nasal sprays. Cortisone nasal sprays are very effective in reducing the inflammation that causes swelling, sneezing, and a runny nose. Cortisone can also decrease the formation of many chemicals involved in the allergic response. Many cortisone nasal sprays are on the market through prescription only. Intranasal steroids are typically the first-line medications for patients suffering from persistent allergies. Fluticasone (Flonase) is one medication available over the counter.

Cromolyn is also an anti-inflammatory medication available over the counter. Although cromolyn is not as potent as cortisone, it is very safe. Cromolyn must be used well in advance of anticipated allergy symptoms to be useful. Ipratropium (Atrovent) nasal spray is available for drying a wet runny nose. It will not prevent allergic reactions. This is an atropine derivative and although usually very safe, a person sensitive to atropine should be cautious when taking this drug.

Montelukast (Singulair) is an inhibitor of leukotriene action, another chemical involved in the allergic reaction. This medication is used for therapy of asthma and has also been approved for treatment of allergic rhinitis, but it is not a first-line therapy. It has been shown to be most effective in those for whom significant congestion is a primary complaint. It may also be used in some cases together with antihistamines.

If antihistamines and nasal sprays are not effective or not tolerated by the patient, other types of therapy are available. Allergy desensitization or immunotherapy may be needed. Allergy immunotherapy stimulates the immune system with gradually increasing doses of the substances to which a person is allergic. Because the patient is being exposed to the allergy-inducing substance, an allergic reaction can occur and this treatment should be supervised by a physician. Although the exact way allergy desensitization works is not completely known, allergy injections appear to modify or stop the allergic reaction by reducing the strength of the IgE and its effect on the mast cells. This form of treatment is very effective for allergies to pollen, mites, cats, and especially stinging insects (for example, bees). Allergy immunotherapy usually requires a series of injections (allergy shots) and takes three months to one year to become effective. The required length of treatment may vary, but three to five years is a typical course. Frequent office visits are necessary.

The duration of the effect of allergy immunotherapy should last many years, if not a lifetime. Although rare, serious allergy reactions can occur while receiving allergy injections. One cannot predict who will have a severe reaction. Even after years of receiving allergy shots, a patient can experience a reaction.

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Medically Reviewed on 1/3/2020
References
https://acaai.org/allergies/types/sinus-infection

https://acaai.org/allergies/types/hay-fever-rhinitis
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