Healthy Living

Cold vs. Allergy: How to Tell the Difference

Cold vs. Allergy: How to Tell the Difference?

It is very common to assume that anyone with the sniffles is contagious. Very often, however, those sniffles are not linked to anything contagious at all--they can be related to other factors. The first thought of many individuals when they suffer from a runny nose, nasal congestion, coughing, or sneezing is that they have a cold, rather than the possibility that they have an allergy. Let us learn in detail the difference between a cold and an allergy and how to distinguish one from the other.

Colds are not allergies and vice versa. Both of them need different diagnosing techniques and modes of treatment to keep their symptoms at bay. Unfortunately, there is no cure for either of them, and the medications that are currently available only reduce the impact of the symptoms on the individual.

Understanding colds and allergies

A cold, also called “the common cold,” is a form of virus. There are more than 100 different types of cold viruses in the environment. Most types share similar characteristics, with certain changes in the symptoms and severity of the condition. A cold can be easily passed from one person to another through the air by sneezing, coughing, or touching someone else with contaminated hands.

The common symptoms of a cold are a runny or stuffy nose, sore throat, and cough. A person suffering from a cold will rarely experience itchy or watery eyes. If the cold gets severe, it leads to a rise in body temperature, followed with pain in the body. For those suffering from a cold, recovery happens quickly enough--7 to 10 days on average. However, if the symptoms last more than a week, it could be a different type of infection.

People can catch cold anytime of the year, although it is more common during the colder seasons, i.e., fall and winter. Young children have a tendency to catch cold far more easily than adults, since their immune systems are not as developed as those of adults and therefore weaker. Individuals suffering from some kind of allergy may also still come down with a cold, further exacerbating their symptoms. 

An allergy occurs when the immune system reacts to a substance it comes in contact with. Those substances that immune systems react to are called allergens. Allergies mostly occur in those individuals whose immune systems are extra-sensitive towards substances. Hence, the moment the body comes in contact with an allergen, the immune system treats it as a foreign, potentially harmful invader, and releases antibodies and other chemicals that cause inflammation. This inflammation is the allergic reaction that a person experiences.

One should note that some of the symptoms of allergies are similar to those of the common cold. The symptoms they have in common are runny nose, nasal congestion, sore throat, coughing, and sometimes, sneezing. If the individual is suffering from postnasal drip, it could lead to a sore throat. In the case of allergies, the eyes could become watery or itchy and also there would occurrence of skin rashes which could lead to blisters, all of these are not present in common cold. In allergies one does not experience fever or pain in the body.


The common cold is usually caused by a virus. One can catch cold from any person infected with a cold virus. This can be due to any kind of physical contact with someone who has a cold or with any surface that has been contaminated with the virus. Common objects that have high chances of contamination are computers, doorknobs, utensils, and other everyday objects. One can also catch cold from the droplets released in the air when an infected individual sneezes or coughs without covering their nose and mouth with a handkerchief.

A cold starts when the virus attaches itself to the lining of the nose or throat. The immune system, which acts as a defense system against germs or bacteria, sends out white blood cells to attack this invader. The nose and throat start to get inflamed, thus creating a lot of mucus. Since so much of the body’s energy is directed at fighting off the cold virus, the individual is left feeling weak and miserable.

Small children can catch cold up to five to seven times in a given year. Since children spend most of their time in daycare, schools, and playgrounds, they are likely to catch the virus very easily. Also, their immune systems are weaker than that of adults and not always strong enough to fight all the bacteria and viruses to which they, children, are exposed.

Seasonal allergies are quite common, because many individuals are allergic to pollen. But allergies can also happen any time of the year. There are various factors that make individuals have allergies. The cause could be genetic. When someone in an individual's family suffers from some allergy, there is a risk that the individual has or will develop an allergy as well. Also, if an individual has some form of allergy, such as pollen allergy or latex allergy, he or she could also be allergic to drugs or dust mites. There are various substances that trigger allergies. Among the most common allergens are animal dander, dust mites, mold, pollen from grass or weeds, latex, certain types of food, drugs, and insects.


A key difference between a cold and allergy is in how long the symptoms normally last. The common cold lasts for about a week up to ten days, whereas an allergy can take up to several weeks to clear up, especially when the allergen is present in the air. A good way to tell between a cold and an allergy is by checking the history of the symptoms. When it comes to allergies, the symptoms usually appear during a certain season and are related to the environment of the individual. One example would be where an individual experiences certain symptoms whenever he is around grass or working in an environment that has something specific, such as metals or latex.

Allergies can lead to a runny nose, but it can also lead to sinus congestion, although less frequently. When the mucus is thick, it is more likely linked to a cold.

A number of symptoms are pretty much similar between the common cold and an allergy. These are the following:

When to reach out to the doctor?

It is not easy always to tell the difference between a cold and an allergy. Therefore, the best thing to do, especially when the symptoms tend to worsen or last more than two weeks, would be to reach out to a doctor for a diagnosis. Doctors can quickly identify the difference and say whether the symptoms are due to an allergy by conducting a skin patch test or a skin prick test. Once the doctor identifies the allergen that has been causing trouble, they can prescribe you the appropriate treatment plan.


cold cannot be treated as there is no cure for the common cold. But there are medications available that help provide relief from the symptoms until the cold subsides on its own. These medications include the following:

  • Decongestant sprays: These are not recommended for children and should only be used by adults and by prescription of a doctor. The duration of their use should not be extended beyond the prescribed period.
  • Painkillers such as acetaminophen or ibuprofen.
  • Cough syrups: These are commonly available over the counter, but for infants, it is always best to check with the doctor instead of just going with any medicine.

It is always best to check with your doctor before going for any over-the-counter medicine. This becomes especially important in cases where the individual is also suffering from some other medical condition. Make sure not to use any cold medicine for a longer duration than recommended, since it can lead to health hazards or, in certain cases, cause damage to the liver. If not comfortable with manufactured drugs, one can try certain home remedies, which are mostly free from side effects. Here are a few of these remedies:

  • Gargle with saltwater at least three to four times a day.
  • Use saline nasal sprays.
  • Increase your intake of fluids such as water, but avoid or lessen caffeine and go for green tea or herbal tea instead.
  • Use a humidifier.

Since a cold is a virus, using an antibiotic will not work. However, if the cold leads to a sinus infection, then one can ask a doctor to prescribe an antibiotic.

The symptoms of an allergy can also be treated with the help of medications. Doctors can recommend antihistamines such as Benadryl or Zyrtec, which are often given as a first course of treatment. But medications do not cure allergies. If a person is allergic to a substance, the allergy will always be there, and exposure to the allergen will trigger the symptoms. The medications are only given to help the individual from the discomforting symptoms. Antihistamines work by blocking the reactions of histamines towards the allergens. By doing so, it helps reduce the symptoms or allergic reactions. However, antihistamines have their own side effects, such as drowsiness. If the allergy becomes severe, the doctor may also prescribe a decongestant to provide relief from sinus congestion. Decongestants work by breaking up the congestion and drying up the sinuses. However, if decongestants are taken for a duration longer than prescribed, they can actually worsen the problem instead of improve it.

Since allergies cannot be cured, medications only help to alleviate the symptoms caused due to the allergic reaction. The best way to manage an allergy is therefore to avoid the substance that triggers the allergy as much as possible. A doctor diagnoses an allergy and determines its cause, after which one needs to take care to stay away from that particular substance as much as possible. However, when it is not possible to avoid the allergen then the symptoms can be treated through medicine, the main one being different from that used for a cold. Doctors can also decide to give you allergy shots to get the allergy under control. The process of allergy shots involves giving small amounts of allergen to the individual for a period of several months. With allergy shots, the main aim is to get the body used to the allergen that has been causing the symptoms. As time passes, the body gets used to the allergen, and the tolerance level towards the allergen builds up, thus leading to a decrease in the symptoms.

How to spot the difference?

Here are certain questions that can help determine whether the individual is experiencing a cold or an allergy:

When did the symptoms start to appear and how quickly did they appear? If the symptoms appear gradually over a period of one to two days, then they are probably linked to a cold. However, if the symptoms suddenly appear out of nowhere, they are probably linked to an allergic reaction.

What is the duration of the symptoms? On one hand, the symptoms of a cold last for a week or two, then gradually go away. On the other hand, the symptoms of an allergy last so long as the individual is exposed to the allergen.

Is there any predictability in the symptoms? If an individual experiences symptoms every time he is exposed to a certain substance or about the same time every year, then the symptoms are likely linked to an allergy. A cold, meanwhile, lacks this predictability or pattern, since one can catch a cold anywhere and at any time of the year.