Decoding the Symptoms: Common Colds vs. Allergies

It’s that time of the year again. Pollen levels around the country are rapidly increasing at the same time that some of my patients are catching cold viruses at the tail-end of winter. How can you tell if your runny nose and watery eyes are a result of allergies or a cold virus? Sometimes it’s difficult to decode the symptoms, but I have some quick tips for telling the difference between the two. I also have some treatment options that will help you make it through spring without having to buy extra tissues!

What causes respiratory allergies?

If you have allergies, you are not alone. Nearly 50 million other Americans have them, too. In fact, allergies are the fifth leading chronic, or long-term, disease in the United States, and the third most common chronic disease among children under 18-years-old.

Allergic reactions are caused by an over-reactive immune system. Sometimes the body mistakes a harmless substance (like pollen or dust) for a dangerous invader. This results in a release of chemicals from immune cells, which can cause sneezing, itchy, runny nose or eyes, rashes or hives, inflamed eyes, skin, or lungs. In severe allergic reactions, whole body reactions may require immediate medical attention.

What causes the common cold?

The common cold is caused by viruses (mainly rhinoviruses) that get into the cells lining the nose, pharynx, and bronchi. The body’s immune system reacts to these viruses in that it opens up blood vessels and increases mucus secretion. This leads to the common cold symptoms including stuffy nose, sore throat, and cough.

Types of allergies

There are six main types of allergies

  1. Indoor/Outdoor Allergies (allergic rhinitis or “hay fever”): Most commonly triggered by tree, grass, and weed pollen; mold spores; dust mites and cockroach allergens; and cat, dog, and rodent dander.
  2. Eye Allergies (allergic conjunctivitis): Most commonly caused by the same things that trigger indoor/outdoor allergies, but symptoms are specific to the eyes.
  3. Skin Allergies (atopic or contact dermatitis): Most commonly triggered by plants such as poison ivy, oak, and sumac. However, skin contact with cockroach and dust mite allergens, certain foods, or latex may also trigger symptoms of skin allergies. Symptoms of skin allergies include eczema or hives.
  4. Latex Allergies: Latex is most commonly found in hospital gloves and certain paints. Latex can react with sensitive skin or can be inhaled and cause breathing problems.
  5. Food and Drug Allergies: The majority of food allergies are caused by eight types of foods: milk, soy, eggs, wheat, peanuts, tree nuts, fish, and shellfish. Penicillin is the most common drug allergy, though there are many other drugs that may cause allergic reactions.
  6. Insect Allergies: Most commonly caused by bee and wasp stings, venomous ant bites, and cockroach and dust mites.

Colds and allergies: What’s the difference?

Many of my patients are not sure how to tell the difference between a common cold and allergies. It’s easy to get confused, since colds and allergies share some (but not all) of the same symptoms. Here’s how you can tell if your symptoms are related to a cold virus or allergies:

  • Duration: Colds don’t usually last longer than 5 to 7 days, but allergies can last as long as you’re exposed to the thing you’re allergic to, the allergen.
  • Onset of Symptoms: Cold viruses take about three days (from the time of infection) to cause symptoms. The sneezing, watery eyes, etc., from an allergy can happen as soon as you are in contact with the allergen.
  • Allergy Symptom Characteristic: Allergies never cause a fever or body aches. The following symptoms are more common in allergy sufferers (though can sometimes be associated with colds, too): itchy, watery eyes; clear mucus that doesn’t turn yellow; and symptoms that are triggered when seasons change.
  • Cold Symptom Characteristics: The following symptoms are more common in cold virus infections (though they can sometimes be associated with allergies, too): cough; sore throat; thick, yellow mucus; and winter-time onset. Unlike allergies, the common cold is often accompanied by fever and body aches.

For more tips, take a look at our Common Colds vs. Allergies checklist.

Can I prevent myself from getting a cold?

While there is no way to guarantee that you won’t catch a cold virus, there are two ways to greatly reduce your risk:

  1. Hand washing and hygiene
  2. Avoiding contact and preventing virus spread

For more information on preventing yourself from getting a cold, see my other article, “Prepping My Patients for Cold and Flu Season.”

Can I prevent myself from getting allergy symptoms?

In terms of preventing allergic reactions, the first step is to find out what you’re allergic to. Doctors who specialize in allergy and immunology can help patients discover what might be causing their specific allergies with skin, patch, and blood tests. For example, sometimes it’s difficult to know if your allergy trigger is pollen, pets, mold spores, or a combination of different triggers. Once you have an understanding of your allergy trigger(s), it’s best to avoid contact with them as much as possible. Depending on the category of allergy that you have, you may want to try the following:

  • Reduce Allergens in the Home: Frequent dusting, vacuuming, and cleaning (wear a face mask to prevent breathing in dust and dander while cleaning) can reduce allergy triggers. Dehumidifiers and air filters can be helpful in cleaning mold and pollen from the air. Keep windows and doors shut during high pollen seasons. Keep pets out of the bedroom if you’re allergic to their dander; that way you get 7-8 hours of dander-free time each night when you sleep. If dust mites are a trigger, washing your sheets in very hot water or putting them in a hot drier for at least 20 minutes can kill them. Allergen-proof bed covers and washable toys are also helpful.
  • Reduce Your Exposure Time: If your allergy trigger is pollen, showering after you come indoors can help to reduce exposure time. Some people find glasses or sunglasses helpful in reducing the amount of pollen that enters the eye and facemasks can help to reduce the number of particles inhaled. Avoid walking outside during peak pollen times (10 a.m. – 4 p.m.) and keep your vehicle windows up to prevent pollen from entering into your car.

What are my treatment options for allergies?

Although allergies can be greatly reduced by avoiding your specific allergic triggers, sometimes it’s impossible to avoid them. In these cases, the following OTC allergy medications may be appropriate and helpful:

  • Antihistamines: During an allergic reaction, the body releases a substance known as histamine. Histamine causes tiny blood vessels in the nose and throat to become leaky, resulting in tissue swelling and increased mucus production. Histamine may also cause constriction of the smooth muscle in the airways, and can produce asthma symptoms. Antihistamines work by preventing this histamine release. This relieves itching, sneezing, and runny nose. OTC antihistamine tablets for adults and syrups for children are available.
  • Nasal Decongestants: Nasal decongestants reduce swelling in your nasal passages and make it easier to breathe. Some OTC allergy tablets combine an antihistamine with a nasal decongestant. Nasal decongestants active ingredients are available in both oral and topical medicines. Topical nasal decongestants are applied directly inside of the nose in the form of drops or sprays. Topical nasal decongestants should not be used for more than three days in a row, however, because frequent or prolonged use may cause nasal congestion to recur or get worse.
  • Nasal Allergy Symptom Controllers (Mass Cell Stabilizers):  Like antihistamines, nasal allergy symptom controllers (also known as mast cell stabilizers) also reduce the effects of histamine, but in a different way. Nasal allergy symptom controllers reduce how much histamine is released into the body when a person has an allergic reaction. The nasal allergy symptom controller ingredient contained in OTC allergy medicines is cromolyn sodium.  Nasal allergy symptom controllers containing cromolyn sodium are applied directly inside of the nose. They are available to consumers over the counter in the form of nasal sprays.

What are my treatment options for colds?

Unfortunately, there is no cure for a cold virus once you’ve been infected. The good news is that there are many over-the-counter (OTC) medications and products that can treat your symptoms. If extra rest, drinking hot fluids, nasal irrigation, and saline gargles and washes are not enough to manage your cold symptoms, you could benefit from:

  • Pain Relievers and Fever Reducers: Ibuprofen, aspirin (for adults), and acetaminophen, can be used to reduce fever and aches.
  • Cough Suppressants: Cough suppressants are helpful if your cough is keeping you awake at night, or is making you uncomfortable. Dextromethorphan is the most common active ingredient in OTC cough medicines.
  • Cough Expectorants:  Sometimes cold viruses trigger the body to produce a large amount of thick mucus. If you feel that you are having trouble coughing out the mucus because it is too thick, guaifenesin-based medications can be helpful.
  • Nasal Decongestants: The membrane in your nose can swell with a cold making it harder to breathe through your nose. Decongestants reduce this swelling. Pseudoephedrine andphenylephrine are the two most common active ingredients in OTC decongestants. There are also nasal decongestant sprays available, but they should not be used for more than three days at a time.
  • Multi-Symptom Cold Medicines: Multi-symptom cold medicines often contain a combination of active ingredients to treat pain, fever, nasal and chest congestion, and cough. While these medications may provide extra convenience since they treat a variety of symptoms, it’s really important to only take medications that treat your specific symptoms and to avoid taking two medications with the same active ingredients.

Always read the Drug Facts label on all types of medications before you take them. It’s possible that some active ingredients may be in more than one medicine. Also, please note that young children (under 4 years of age) should not be given certain cough and cold medicines; check with your pediatrician before giving any medicine to young children and babies. See the tip sheet, “Giving Oral OTC Cough and Cold Medicines to Children,” for more information.

It’s important to work closely with your doctor to determine the best allergy management strategy, depending on your living and work environment and unique sensitivities. With careful diagnosis and treatment, most people can find a way to manage their allergies successfully. Don’t lose heart if you’re struggling with allergy symptoms – a physician can help you develop a plan to improve your situation. And if you have a cold instead of allergies – be encouraged that most cold viruses fully resolve in a week or two, and that rest, fluids, or OTC medications can help you manage your symptoms more comfortably.

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Fun Fact

Q: What medical condition did the scientist who discovered cromolyn sodium suffer from?

A: Asthma. Dr. Roger Edward Collingwood Altounyan (1922–1987) was a Syrian Armenian physician and pharmacologist who discovered cromolyn sodium (which he isolated from an Egyptian plant-based muscle relaxant) as a remedy for asthma.