While a common cold, including chest cold and head cold, can be caused by more than 200 viruses, influenza is a viral infection that attacks your respiratory system - your nose, throat and lungs. Allergies on the other hand, are caused by an overactive immune system.

A key reason why colds are so common in children is because kids spend time at school or in day care centers where they are in close contact with other kids most of the day. Also, children's immune systems aren't yet strong enough to fight off colds. Children have about 5-7 colds per year, but in families with children in school, the number of colds per child can be as high as 12 annually.

Adults average about two or three colds a year, although the number ranges widely. Women, especially those 20 to 30 years old, have more colds than men, possibly because of their closer contact with children. On average, people older than 60 have less than one cold a year.

Symptoms

If you tend to get "colds" that develop suddenly and occur at the same time every year, it's possible that you actually have seasonal allergies. Although colds and seasonal allergies may share some of the same symptoms, they are very different conditions. So how can you 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.

Cold symptom characteristics:

The common cold is a group of symptoms in the upper respiratory tract which include cough; sore throat; sneezing; thick, yellow mucus; nasal congestion; and watery eyes. Unlike allergies, the common cold is often accompanied by more severe symptoms, such as high fever or muscle aches, which may indicate you have flu rather than a cold.

Allergy symptom characteristic:

Allergies never cause a fever or body aches. Symptoms include: itchy, watery eyes; clear mucus that doesn’t turn yellow; and symptoms that are triggered when seasons change. Although there are some differences, cold and allergy symptoms overlap quite a bit. The most important difference is that colds don't last longer than 14 days. If you still have symptoms after two weeks, these may be allergy symptoms.

Although cold and nasal allergy symptoms are rarely serious, they can sometimes lead to other problems, such as sinus infections. Colds may also lead to a middle ear infection. If you think you might have allergies, or your cold symptoms seem severe, see your doctor.

Flu symptoms characteristic:

Initially, the flu may seem like a common cold with a runny nose, sneezing and sore throat. But colds usually develop slowly, whereas the flu tends to come on suddenly. And although a cold can be a nuisance, you usually feel much worse with the flu. Common signs and symptoms include: fever over 38°C; aching muscles, especially in your back, arms and legs; chills and sweats; headache; dry cough; fatigue and weakness; and nasal congestion.

Causes and triggers

With a common cold, you catch the virus from another person who is infected with the virus. This usually happens by touching a surface contaminated with cold germs - a computer keyboard, doorknob, or eating utensil, for example - and then touching your nose or mouth. You can also catch a cold by encountering secretions someone with a cold has sneezed into the air. While getting chilled or wet is not a cause of common colds, there are factors that make you more susceptible to catching a cold virus. For example, you are more likely to catch a common cold if you are excessively fatigued, have emotional distress, or have allergies with nose and throat symptoms.

Allergies are caused by an overactive immune system. For some reason, your body mistakes harmless substances, such as mold or pollen, for germs and attacks them. Your body releases chemicals such as histamine, just as it does when fighting a cold. This can cause swelling in your nasal passages, a runny nose, coughing, and sneezing. Allergies are not contagious, although some people may inherit a tendency to develop them.

Flu viruses travel through the air in droplets when someone with the infection coughs, sneezes or talks. You can inhale the droplets directly, or you can pick up the germs from an object, such as a telephone or computer keyboard, and then transfer them to your eyes, nose or mouth.

Treatment options

It’s hard to find good relief for a cold. But there are various treatment options available, such as decongestants or antihistamines, nasal sprays, cough medicines and cough syrups, and pain medication. You just need to figure out what works for you and what doesn’t. Just remember that common colds are viral, not bacterial. Yet many people still ask their doctors for antibiotics when they experience common cold misery. Antibiotics kill bacteria, not viruses. Antibiotics cannot help a viral infection such as a cold. Sometimes, common colds can lead to bacterial infections in your lungs, sinuses, or ears that require medical treatment such as antibiotics.

Treatment of seasonal allergies may include over-the-counter or prescription antihistamines, nasal steroid sprays and decongestants, and avoidance of exposure to allergens where possible. Nasal steroids reduce swelling in the nasal passages, relieving congestion and other symptoms. Allergy shots, called immunotherapy involves being injected with a small amount of the substance to which you are allergic. Over time, the dose is increased. By exposing you to greater and greater amounts of the allergen, your body may develop a tolerance to it.

To treat flu, you’ll usually need nothing more than bed rest and plenty of fluids. But in some cases, your doctor may prescribe an antiviral medication. If taken soon after you notice symptoms, these drugs may shorten your illness by a day or so and help prevent serious complications.

Prevention

Your best protection from the common cold is frequent hand washing. Amazingly, about 80% of contagious diseases are transmitted by touch. But the simple friction that occurs when you rub skin against skin while using warm water and soap and then follow that with thorough rinsing and drying gets rid of potentially harmful germs. While germs are often transferred to others through household objects, the biggest transportation center for germs is your hands. That's why frequent hand washing gets rid of the illness-causing germs and helps to prevent the spread of some diseases, especially if a family member, friend, or classmate has a cold or flu virus.

To prevent allergy symptoms, avoid substances you're allergic to, called allergens. If you're allergic to pollen, for instance, avoid going outside on days when the pollen count is high. Common allergens include pollen, mold, animal dander (flakes of dead skin), dust mites and believe it or not, cockroaches! 

When it comes to preventing flu, the influenza vaccine isn't 100 percent effective, so it's also important to take measures to reduce the spread of infection:

• Wash your hands. Scrub your hands vigorously for at least 15 seconds. Or use alcohol-based hand sanitizers if soap and water aren't readily available.
• Contain your coughs and sneezes. Cover your mouth and nose when you sneeze or cough. To avoid contaminating your hands, cough or sneeze into a tissue or into the inner crook of your elbow. 
• Avoid crowds. Flu spreads easily wherever people congregate - in child care centres, schools, office buildings, auditoriums and public transportation. By avoiding crowds during peak flu season, you reduce your chances of infection.