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Cold Sores - Causes, Symptoms, Risk Factors, Diagnosis, and Treatment

Published on Mar 11, 2022   -  4 min read


Infection around the border of the lips due to the herpes simplex virus is known as cold sores. To know about it in detail, read the article below.


What Are Cold Sores?

Cold sores are most commonly referred to as fever blisters or tiny blisters caused by a viral infection. They are typically small in size and filled with fluids that occur on and around the lip region. In most cases, these blisters tend to group together and produce a patch-like appearance. These cold sores can spread from one affected person to another through close contact, like kissing.

These cold sores last only for two or three weeks and leave without causing any scars or marks. When the fluid-filled blisters break, scab forms, and it lasts for at least three to four days before falling off. Even when the sores are not visible, the cold sores tend to spread. It can also spread to another person’s mouth or genitalia when involved in oral sex.

What Are the Causes of Cold Sores?

As mentioned earlier, cold sores are caused due to viral infection. The main virus that is responsible for causing cold sores is a certain strain of the herpes simplex virus (HSV). To be more descriptive, HSV-1 causes cold sores, whereas HSV-2 is responsible for genital herpes. But both these have the danger of spreading to another person’s mouth or genitalia through close contact and oral sex.

Cold sores are most contagious when the fluids from the blisters are oozing out since these fluids are easy to spread through contact. But it is also possible for the virus to get transmitted even if there are no blisters. It has been observed that many cases of cold sores have not exhibited any signs or symptoms.

There is a possibility of the herpes virus being present dormant in the nerve cells after an episode of the infection. This means that there are chances of getting another cold sore exactly at the same spot as before. These recurrences might be triggered by the following factors.

  1. Stress.

  2. Fever or viral infection.

  3. Hormonal changes.

  4. Fatigue.

  5. Sunlight exposure.

  6. Injury to the skin.

  7. Change in immunity.

What Are the Symptoms of Cold Sores?

The signs and symptoms of cold sores may vary depending on whether the person is getting the sores for the first time or if it is a recurrence. There are three different phases throughout the lifetime of the cold sore. They are:

Itching and Tingling: Upon getting the infection, many would experience itching, tingling, or burning sensation on and around the lips. During this time, there will be no signs of blisters or pain.

Blisters: After a day or two of the irritation, small, hard, and fluid-filled blisters begin to erupt along the borders of the lip. There is a possibility of these blisters showing up on the cheeks and around the nose.

Oozing and Crusting: These blisters might start to combine and form patches that eventually burst and ooze out fluids. This leads to the formation of scabs, and then the healing process begins.

The signs do not appear for the first time and until after 20 days of initial exposure to the virus. Recurrence usually occurs at the same spot and is comparatively less severe than the first infection. Some of the common symptoms for a first-time outbreak include:

What Are the Risk Factors of Cold Sores?

There is no specific group of populations that is more susceptible to cold sores. In fact, almost every person has the risk of getting a cold sore. Though there are no symptoms, almost all adults serve as a carrier for carrying the virus that causes cold sores.

One main factor that plays a vital role in the development of cold sores is due to a weakened immune system. It can be due to other medical conditions or treatments such as:

How Are Cold Sores Diagnosed?

Cold sores are very easily diagnosed. The doctor will have a look at the blisters and directly confirm cold sores. If in case there is a need to confirm the diagnosis, a sample might be taken from the blisters, which is sent to the laboratory for testing. Apart from these, there are no other methods required for diagnosing cold sores.

How Are Cold Sores Treated?

Cold sores are often left untreated, and it goes away on their own in two weeks to four weeks. If the doctor feels the requirement of any antiviral medications in order to speed up the healing process, then there are different prescription medicines that are available. They are:

These medicines are available in different forms as well. For instance, some of these medicines are available in the form of pills that can be taken orally, and others are available in the form of creams, which can be applied over the blisters or the sores as per the doctor’s direction. Usually, the doctor will advise applying the creams two to three times a day.

In terms of efficiency, it has been said that the pills work better than the creams. In cases of utmost severe infections, antiviral drugs are given in the form of an injection to help fight the infection.

How to Prevent Cold Sores?

The main concept behind the prevention of cold sores is to maintain personal hygiene and avoid all the things that trigger cold sores. If the sores are caused due to sun exposure, proper sunblock or oral antiviral drugs (prescribed by the doctor) help to prevent them. Also, if a person is getting cold sores more than nine times a year, then the doctor will prescribe an antiviral medication which is to be taken on a regular basis to avoid any further recurrence.

Avoid the following in order to prevent yourself from catching the infection from other persons.


Cold sores are not a severe health condition; generally, it goes away on their own without any medical intervention. The treatment focuses on managing the outbreak and speeding up the healing process. If the recurrence is very frequent, reach out to your doctor to get antiviral medications that can be helpful in reducing the intensity and the frequency of the outbreaks.


Last reviewed at:
11 Mar 2022  -  4 min read




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