Cold Sore: Symptoms, Causes, Risks, Complications, Stages, Treatment and Prevention

A face of a women with cold sore next to her mouth


The mouth is an important part of the body because it’s where people eat. Moreover,
if a problem occurs in the mouth and lips, it could affect activities like eating and talking.

One common health problem affecting the mouth is a cold sore. A cold sore, also known as fever blisters, are caused by a virus, known as the herpes simplex virus (HSV-1). These are found in the mouth and lips, but can also occur anywhere in the body. They look like tiny but fluid-filled lesions or blisters around the lips. They usually seen in patches and can spread from one person to another through close contact like kissing.

There is no current cure for this infection and the blisters may recur. However, the infection is self-limiting, which means they will clear up between 7 and ten days without treatment. In some cases, treating the sores with antivirals are recommended.


Cold sores, also dubbed as fever blisters, can appear anywhere in the body.However, they’re most likely to occur on the outside of the mouth and lips. In some cases, they appear on the fingers, cheeks, and nose.

The common signs and symptoms include:

Tingling and itching – The cold sore may cause a burning, itching or tingling sensation around the lips before the blister would appear.

Blisters – The fluid-filled blisters will appear on the outside of the mouth or around the lips. The blisters would break out along the border where the outside edge of the lips meets the facial skin.

Oozing and crusting – The tiny blisters may merge and burst, leaving an open sore that is colored yellow. In some cases, it will ooze fluids and then a crust will form.

The patient may feel signs and symptoms during the first outbreaks like painful gums, fever, headache, sore throat, muscle pain and inflamed lymph nodes.

The signs and symptoms of cold sore in children

Children who are younger than five years old may have symptoms such as irritated or inflamed gums, small and painful sores in and around the mouth, sore throat, increased saliva production, and fever is reaching about 38 degrees C or 100.4 degrees F. Kids are also prone to headaches, nausea or feeling sick and dehydration.

Signs and symptoms in adults

Cold sore or primary simplex viruses are rare in adults, but the signs and symptoms are similar to those experienced by kids.

Recurrent cold sores

In some people, they are prone to recurrent cold sores which last for less time and are less severe than primary infections.

The other signs and symptoms of cold sore includes:

  • Mouth or tongue pain
  • Swollen lips
  • Swallowing difficulties
  • Blisters or lesions on the mouth and tongue
  • Sore throat
  • Elevated body temperature
  • Dehydration
  • Headaches
  • Nausea

The doctor will diagnose the cold sore depending on the visible signs in the oral area.
Those with previous experience of a cold sore will easily recognize a reinfection or recurrence. The signs and symptoms are usually clear for the doctor to make a diagnosis. In some cases, they need to request a blood test. Others can take a sample of the fluid or scraped tissue to be tested in the laboratory for the presence of the virus.


The herpes simplex virus is the causative agent of cold sores. It has two types – the herpes simplex type 1 virus (HSV-1) and the herpes simplex type 2 virus (HSV-2). HSV-1 is the common causative agent of cold sores while the HSV-2 causes genital warts.

Cold sores are contagious when oozing lesions or blisters are present. The virus can be transmitted to others even if there is no present blister. This can be passed through kissing, eating with shared utensils, using shared razors, towels, and other personal items. Oral sex could also transmit the virus to the genitals.

Cold sores can also recur if there are triggers, including:

  • Fatigue
  • Stress
  • Exposure to the wind or sunlight
  • Viral infection or fever
  • Changes in the immune system
  • Hormonal changes
  • Respiratory tract infection
  • Emotional upset
  • Psychological stress
  • Tiredness
  • Injury to the affected area

4Risk Factors

About 90 percent of adults across the globe test positive for the herpes simplex type 1 virus (HSV-1). Once a person has the virus, this may reactivate.

Some people who have compromised immune systems are at a higher risk of the condition or complications. The conditions that increase the risk of complications include:


Initial infection of herpes simplex can cause severe signs and symptoms. It could also lead to severe complications since the body is not used to the virus and hasn’t produced a defense against it yet.

Though the complications are uncommon, if these are present, call a doctor immediately.

  • Difficulty swallowing
  • Difficulty breathing
  • Red and irritated eyes
  • Persistent high fever

The other complications include infection of the fingers, called herpes whitlow, vision problems or blindness, widespread irritation and infection of the skin and infection of the brain and spinal cord.

6Stages of a cold sore

There are certain stages of a cold sore appearance and progression.

Initial symptoms – In more than 85 percent of people with a cold sore, the outbreak often starts with a tingling sensation, itching, tightness and soreness around the lips.
These happen about one to two days before the lesion or blister appears.

Progression – The second stage of the disease is progressing. This means that as the infection develops at about two to four days of an outbreak, fluid-filled blisters begin to appear and form. This is due to the virus waking up and multiplying. Also, by this time, the body is beginning to defend the body and fight back the virus.

Rupture – This stage occurs at about four to five days of the outbreak. The blisters can burst and this can cause pain. The exposed and ulcerated sore will begin to crust and scab. The body now goes into the healing process.

Scabbing – At around five to eight days of the outbreak, scabs may form. These are itchy and may crack often. In some cases, they may even bleed. Do not pick the blisters because this means that you are nearing the end of the flare-up.

Resolution – Once the body has the virus under control, the scabs will start to peel off. This usually happens at around eight to ten days from the start of the symptoms, without medicines. 


Cold sores usually clear up even without treatment within seven to ten days.
However, doctors can prescribe medicines such as antiviral drugs and creams to ease the symptoms to lessen the healing time needed.

When you have cold sores, you need to drink plenty of water to reduce the risk of dehydration, avoid salty and acidic foods, dab the creams on the blisters rather than rubbing them, washing your hands before applying creams and use an antiseptic wash to keep the mouth clean.

Aside from antiviral creams and tablets, the doctor may prescribe cold sore patches. These contain a special gel called hydrocolloid, which is effective in treating wounds.

Simple remedies to try:

Simple remedies can soothe cold sores. These include:

Using lemon balm – Lemon may help reduce swelling and redness. Lemon balm can be used to soothe the blisters. Lemon balm may also protect against recurrent outbreaks.

Ice – Ice may not reduce the period of the outbreak, but it can ease inflammation and pain. You can apply ice packs directly on the sore.

Aloe vera – Aloe vera can be used to soothe the skin affected with a cold sore. It also has anti-inflammatory properties to relieve swelling.

Apply sunscreen – Sunscreen protects the lips from the sun when you have a cold sore. It can also reduce future outbreak when used every day on the lips.

Reduce stress – Stress is a common trigger of cold sore flare-ups. Make sure you manage your stress effectively through techniques such as meditation, avoiding stressful events and regular exercise.


To help prevent being infected with cold sores or to prevent spreading cold sores to other people or the other parts of your body, follow the following precautions:

  • Avoid skin-to-skin contact with others if there are blisters. During this stage, the virus can spread more easily and is more potent to cause infection.
  • Avoid kissing anyone who has a blister or cold sore and does not do oral sex on anyone with genital herpes.
  • Avoid sharing certain objects such as towels, lip balms, lipstick, utensils, and other items where the virus can linger.
  • Keep the hands clean and wash your hands regularly. Proper and regular handwashing can prevent the spread of the virus from one person to another. Always wash your hands before touching yourself, and other people, especially infants.
  • If a cold sore pop up when you’re stressed, practice stress management techniques and do relaxation techniques.
  • If you are prone to developing cold sores from the sun, you can apply zinc oxide lip balm before sun exposure.