Allergic Rhinitis vs. the Common Cold
Although some of the symptoms of these two conditions are similar, first-line treatment differs, making distinction important.
Occasionally, minor medical conditions for which patients seek advice for self-treatment resemble each other. One of the most common conditions presented to pharmacists is the common cold. However, allergic rhinitis, which affects 20% of the U.S. population, mimics the common cold in many respects.
The patient may not be able to distinguish one from the other, but the pharmacist can facilitate patient self-treatment and/or triage. Treatment goals are different for each condition.
Etiologies
Etiologies of the common cold and allergic rhinitis are markedly different. Viruses cause the common cold.
At least half of cold episodes are produced by the the rhinovirus family. Other cold pathogens include coronavirus, influenza A or B virus, parainfluenza virus, respiratory syncytial virus, adenovirus, and enterovirus.
Unlike the common cold, allergic rhinitis is neither infectious nor communicable. This IgE-mediated condition may be caused by a wide variety of allergens. Allergists group the syndrome into two types: perennial or seasonal. Identifying whether symptoms exist year-round (perennial) or occur only at certain times of the year (seasonal), provide clues regarding the specific etiologic agents.
Perennial allergic rhinitis is is caused by an allergen that the patient may have contact with at virtually any time. Examples include automotive exhaust, cosmetics, hair spray components, pillows, cigarette smoke, household cleaning substances, toiletries, upholstery, and house pets. One of the most common perennial offenders is the house dust mite. This microscopic creature is found in incredibly high numbers throughout the house, especially where people spend a lot of time, such as the bedroom and livingroom. The mite ingests protein, including skin cells shed from humans or animals. Patients are usually not allergic to the mite itself, but to the feces it yields to the environment.
Seasonal allergic rhinitis is caused by an allergen present only during certain times of the year. Patients might experience the most severe symptoms when flowering plants are producing pollen, when ragweed is blooming, or when wheat is being harvested. Trees, grasses and all types of weeds may sensitize patients. During the rainy season, residual moisture causes rampant growth of molds and mildews, other common causes of seasonal allergic rhinitis.
Manifestations
Common cold symptoms vary somewhat depending on which viral invader is responsible. However, virtually all cold viruses produce some degree of nasal blockage, runny nose, cough, and sore throat. Patients may also experience headache or other body aches, occasional sneezing, weakness, dizziness, and postnasal drip. The patient may also note that one or more family members, coworkers
or playmates have the condition. Symptoms may occur 3–4 times yearly, each lasting for a period of 2–3 days (sneezing, sore throat) to as long as 2 weeks (cough, nasal discharge, postnasal drip, throat clearing).
In contrast to common cold symptoms, which exhibit a gradual onset and slow progression, onset of allergic rhinitis can be sudden. Some allergic rhinitis symptoms are distinctive and others nonspecific. Among the nonspecific symptoms are rhinorrhea and nasal congestion. These are considered two of the cardinal symptoms of allergic rhinitis, and they overlap with the common cold. Other signs and symptoms of allergic rhinitis can help differentiate it from the common cold. For instance, allergic rhinitis produces nasal pruritus, absent in the common cold. Itch often occurs in the posterior nose, where it cannot easily be alleviated. As a result, the patient may wrinkle the nose constantly (“bunny nose”), and may rub the nose upward with the heel of the hand in a gesture known as the “allergic salute.” Allergic rhinitis produces sneezes that are different in both quality and quantity from those of the common cold. Common cold sneezes are infrequent and deep, occurring as an attempt to relieve or clear bronchial or nasal congestion. In allergic rhinitis, implantation
of an allergen on the nasal mucosa causes a paroxysm of sneezes (as many as 10–20), which may be light and relatively quiet. The cold rarely causes ophthalmic problems, which are frequently a component of allergic rhinitis. Allergic patients may complain of a profuse, watery discharge or tearing. They may also exhibit a network of lines (Morgan’s or Dennie’s lines) that extend away from the inner
corner of the eye down-ward in a fan-like pattern. Finally, patients may have blue-black discolorations beneath both eyes. These “allergic shiners” occur when the venous network that drains the infraorbital area anastomoses with nasal vessels that are congested from allergen, causing a backup of venous blood. Allergic rhinitis is more likely than the common cold to affect the sense of smell, causing hyposmia or anosmia. The pharmacist may ask about the patient’s sense of taste, because inability to smell radically reduces the taste of foods.
Counseling Important with Common Cold and Allergic Rhinitis
Certain drugs and conditions contraindicate some self-treatments for allergic rhinitis and the common cold. Ingredients such as dextromethorphan and pseudoephedrine may produce a deadly interaction when taken with monoamine oxidase inhibitors. Phenylpropanolamine (the safety of which has been recently brought into question by the FDA) should never be taken with any other product containing phenylpropanolamine or pseudoephedrine. A sore throat accompanied by fever, headache, rash, inflammation, nausea or vomiting should not be self-treated. Similarly, cough accompanied by rash, fever or persistent headache and chronic cough as seen in smoking, asthma, or emphysema should not be self-treated. Patients with hypertension, diabetes mellitus, thyroid disease or
prostatic hypertrophy should avoid products containing decongestants. Self-treatments may be accompanied by numerous other warnings. Pharmacists should ensure patients understand these warnings and precautions.
Complications
The common cold is a self-limiting condition for most patients, although some develop complications, such as otitis media and sinus infections. Allergic rhinitis is more likely to produce complications because of its recurrence. Patients who have perennial allergic rhinitis may be affected virtually constantly. Thus, allergic rhinitis is now recognized as a risk factor for the development of conditions such as asthma, sinusitis, otitis media, and nasal polyps.
Prevention
With both conditions, prevention is the preferable treatment strategy. The primary method of transmission of the common cold virus is transfer of the virus to the nasal, oral or ophthalmic mucosa through contaminated hands. Seemingly innocuous activities such as wiping a tear from the eye can allow successful inoculation. Washing the hands frequently helps prevent infection.
Prevention of allergic rhinitis is achieved by avoidance of the allergen and control of the environment to eliminate or minimize the allergen (e.g., weekly laundering of bedding, carpet removal, using dust mite sprays, getting rid of pets, smoking cessation, installation of HEPA filters).
How to Treat A Cold and Hay Fever
Two common conditions are the cold and allergic rhinitis (hay fever). They may cause similar symptoms, but the cold is caused by a virus and hay fever is caused by an allergic reaction. Their treatments also differ, but both can be relieved with nonprescription products a pharmacist can help you select.
Treatment for the Common Cold: With the common cold, the nose alternates between being congested and running. Congestion may be treated with a topical decongestant (spray, inhalant, or drops) or an oral nasal decongestant. One example of a topical decongestant is the chemical oxymetazoline, which should be used no more often than every 12 hours. Never exceed the time of use on the label of any spray or drop (usually three days). The chemicals in the product can damage your nose. If you have already been using a drop or spray beyond three days, you must stop to allow the nasal tissues to return to nor-mal. If you choose an oral nasal decongestant, an ingredient such as pseudoephedrine is safe and effective.
The only antihistamines proven safe and effective for runny nose and sneezing of the common cold are clemastine, doxylamine and chlorpheniramine. Sore throat caused by a cold may be self-treated if the pain is minor. Do not treat it more than 2 days. If sore throat lasts more than 7 days, you should see a physician. Lozenges for sore throat contain ingredients such as benzocaine, menthol, dyclonine, phenol/sodium phenolate, hexylresorcinol and benzyl alcohol. Oral painkiller products such as acetaminophen, ibuprofen, ketoprofen or naproxen are also helpful and soothing.
Cough due to colds may be safely treated for as long as 7 days. If the cough is productive (brings up mucus), the ingredient guaifenesin can help break up the chest congestion (water intake is also important). If the cough is dry and hacking, a cough suppressant (dextromethorphan) can stop the cough.
Treatment for Hay Fever: When the problem is hay fever, antihistamines act against the process that causes the symptoms. Many different antihistamines are effective for this purpose and help relieve runny nose, sneezing, nasal itching, and watery, itchy eyes. Recently, eye drops have become available containing naphazoline plus an antihistamine (pheniramine or antazoline). They may help eye symptoms such as tearing, redness or itch. At times, hay fever causes nasal congestion, which is not well treated by antihistamines. You may want to try using decongestant pills containing pseudoephedrine, or adhesive breathing strips, which are placed over the bridge of the nostrils and open up the nasal passages.
Patients may also choose cromolyn sodium nasal solution, which may prevent allergies if used up to one week before contact with an allergen. It also relieves runny/itchy nose, sneezing, and stuffy nose.
Ask Your Pharmacist: Your pharmacist can help you choose products containing the ingredients recommended on this page to treat specific symptoms. Be sure to carefully read all warning and caution labels on products you select. The pharmacist also can tell you if a product should not be used if you take prescription medicine.
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