Cold sores: Causes, Prevention and Remedies

Home >> Dental Diseases >> Cold sores: Causes, Prevention and Remedies
cold sores

Written by Dr. Shruti Dani

Medically reviewed by  Dr. Vidhi Bhanushali Kabade BDS, TCC

Cold sores are a frequent condition that almost everyone has encountered at some time in their lives. The virus known as herpes simplex virus (HSV) causes these tiny, painful blisters that frequently occur around the lips or on the face.

But how do you know ulcer you have is a normal mouth ulcer or a cold sore? In this blog, we will understand in detail about cold sores and most importantly how we can differentiate them from normal mouth ulcers.

Defining Cold Sores

Cold sores, also known as fever blisters, are tiny, fluid-filled blisters that usually form around the lips, though they can also appear on other parts of the face. The primary culprit behind these sores is the herpes simplex virus, with the two most common types being HSV-1 and HSV-2. 

HSV-1 is generally responsible for oral herpes, including cold sores, while HSV-2 is typically associated with genital herpes.


Cold sores are referred to by various names, including fever blisters, oral herpes, or herpes labialis. Irrespective of the terms, they all indicate the same disease caused by the herpes simplex virus.

cold sores


Cold sores may be caused by various factors, they may be external or internal.

External Causes

  1. Direct Contact
  • Cold sores are very infectious and can be spread through direct contact with an affected individual. 
  • Kissing, sharing utensils, or coming into touch with the saliva of someone who has an existing outbreak can cause the infection. 
  1. Touching infected Surface
  • The virus can live on surfaces for a short period. 
  • Touching a contaminated surface and then touching the face can lead to infection.

Internal Causes

  1. Compromised immune system
  • Stress, sickness, or a compromised immune system can make the body more vulnerable to HSV breakouts. 
  • Maintaining a strong immune system is essential for preventing cold sores.
  1. Sun Exposure
  • Overexposure to sunlight, particularly ultraviolet (UV) radiation, can cause cold sore breakouts in certain people. 
  • Using UV-protected lip balms can help avoid this.
  1. Vitamin Deficiency 
  • Vitamin D and Vitamin C deficiency are also an important cause of cold sores eruptions. 

How to differentiate between Mouth ulcers (Canker sores) and Cold Sores?

Cold sores and mouth ulcers are two different oral conditions, each with its own causes, symptoms, and characteristics. Understanding the differences can help individuals identify and manage these issues more effectively.

  • Difference based on Cause:
Cold SoresMouth Ulcers 
Cold sores are primarily caused by the herpes simplex virus (HSV), with HSV-1 being the most common culprit. These highly contagious sores They often appear around the lips but can also occur on the face.Mouth ulcers, on the other hand, can result
from minor injuries, irritation, or certain medical conditions. Unlike cold sores, mouth ulcers are not viral and are not contagious. They can occur on the inside of the lips, cheeks, gums, or on the tongue.
  • Difference Based on Appearance:
Cold SoresMouth Ulcers 
Small, fluid-filled blisters that can burst and form a scab as they heal. They may be accompanied by pain, itching, or a tingling sensation.Round or oval with a white or yellowish centre and a red border They are generally shallow and can be painful, especially when eating or drinking.
  • Difference Based on Location:
Cold SoresMouth Ulcers 
Occur on the outer edge of the lips but can also appear on the face, including the nostrils and chin.It occurs on the outer edge of the lips but can also appear on the face, including the nostrils and chin.
  • Difference Based on Contagiousness
Cold SoresMouth Ulcers 
It is highly contagious, especially when the blisters are present. Direct contact with the sores or the fluid within them can transmit the virus from person to person.It is highly contagious, especially when the blisters are present. Direct contact with the sores or the fluid within them can transmit the virus from person to person.
  •  Difference Based on Underlying Cause
Cold soresMouth ulcers
Primary cause of cold sores is the herpes simplex virus (HSV-1 or HSV-2). Outbreaks may be triggered by factors such as stress, illness, or exposure to sunlightCaused by various factors, including injury (such as accidental biting), certain foods, hormonal changes, stress, or underlying medical conditions.
  • Difference Based on Underlying Duration
Cold SoresMouth Ulcers 
Usually, heal on their own within 1-2 weeks; larger or more severe ulcers may take longer.Usually heal on their own within 1-2 weeks; larger or more severe ulcers may take longer.


Cold sore prevention involves a mix of lifestyle changes and awareness. Here are some tips:

  1. Avoid Direct Contact: Avoid kissing or exchanging personal goods with someone who is experiencing an outbreak.
  2. Practice Good hygiene: Wash your hands often, especially after touching your face or contacting potentially contaminated surfaces.
  3. Boost Immunity: Maintain a healthy lifestyle that includes a balanced diet, frequent exercise, and appropriate sleep.
  4. Use Sunscreen: Apply lip balm with UV protection to shield the lips from the sun’s harmful rays.

Home Remedies

While there is no cure for the herpes simplex virus, certain home remedies can help in relieving symptoms:

  1. Ice Packs: Applying ice to the affected area can reduce pain and inflammation.
  2. Lip Balms: Keep the affected area moisturized with a lip balm containing ingredients like beeswax or coconut oil.
  3. Over-the-Counter Creams: Antiviral creams containing docosanol or acyclovir may help shorten the duration of an outbreak.


Antiviral medications prescribed by a healthcare professional can help manage and reduce the severity of cold sore outbreaks. These medications are most effective when taken at the first sign of symptoms.


While cold sores can be common and annoying, they may be treated with appropriate care and awareness. Individuals can overcome the difficulties of cold sores more effectively by recognizing the causes, practicing prevention, and adopting remedies at home when necessary. If symptoms persist or worsen, it is best to visit a healthcare professional for proper medical management.

Was this article helpful?