Cold Sores – Causes, Symptoms, Treatments

What are Cold Sores?

Cold sores are small, fluid-filled blisters that typically appear on your lip or around your mouth. They are caused by the herpes simplex virus type 1 (HSV-1), a very contagious virus. 

Globally, an estimated two-thirds of people under 50 are infected with herpes simplex virus type 1 (HSV-1), the virus that causes cold sores. This translates to roughly 3.7 billion people worldwide.

While a large portion of the population has HSV-1, not everyone experiences outbreaks. 

Estimates suggest that 50% to 80% of adults in the US have oral herpes, but some may never have a single outbreak. For those who do experience outbreaks, the frequency can vary greatly. Some people have rare outbreaks, which can happen just once or twice in their lifetime, while others may get outbreaks several times a year. 

The first time you experience a cold sore outbreak, it can be quite severe. You may experience flu-like symptoms in addition to the blisters themselves. However, subsequent outbreaks are usually milder and clear up on their own within a week or two. 

Triggers for Cold Sore Outbreaks 

While you might not experience any symptoms after the initial infection, the virus stays dormant in your nerve cells for life. Certain factors can trigger the virus to reactivate and cause an outbreak of cold sores.

• Weakened immune system: This can be caused by stress, illness (including a common cold), or lack of sleep. When your immune system is compromised, it has a harder time keeping the virus in check.
• Sun exposure: Ultraviolet (UV) light from the sun can be a real trigger for outbreaks. Sunburn can weaken the skin and make it more susceptible to viral reactivation.
• Changes in hormone levels: For some women, hormonal fluctuations around their menstrual period can trigger outbreaks.
• Fever or other illness: As mentioned earlier, any illness can weaken your immune system and create an opportunity for the virus to reactivate.
• Physical trauma or dental work: Injury to the lip or mouth area, or even dental procedures, can irritate the skin and trigger an outbreak.
• Friction: Friction from rubbing or chapping of the lips can also irritate the skin and potentially trigger an outbreak.
• Certain medications: Some medications, such as chemotherapy drugs, can weaken the immune system and trigger outbreaks.

Cold Sore Outbreak Cycle

While all cold sores are caused by the herpes simplex virus, they can appear in different stages and locations and outbreaks typically have a cyclical nature.

The outbreak cycle for cold sores, caused by the herpes simplex virus type 1 (HSV-1), follows five stages:

Prodrome (Tingling or itching):  This is the first stage and can last anywhere from a few hours to a few days. You might feel a tingling, itching, burning, or prickling sensation around your mouth or lip where the cold sore is about to erupt. This tingling sensation can occur anywhere from a few hours to a few days before the blisters appear. Some people may also experience flu-like symptoms, such as swollen glands, headache, or muscle aches, during this stage. 

This tingling sensation is caused by the herpes simplex virus (HSV-1) reactivating in your nerve cells. The virus travels through the nerves to the skin surface, where it replicates and causes the formation of the cold sore blisters.

Blistering: Within 48 hours of the tingling sensation, one or more small, fluid-filled blisters will form on the surface of the skin. The skin around the blisters may be red and swollen. This stage can be quite painful and tender.

Weeping (Ulceration): The blisters may weep clear fluid or pus, and then break open and become ulcers.  Ulcers are shallow, crater-like sores that can be very painful.

Crusting:  After a few days, the ulcers will dry out and crust over. The crust can be yellow, brown, or bloody. It’s important to avoid picking at the scab as this can slow healing and increase the risk of scarring.

Healing: The crust will eventually fall off, revealing healthy skin underneath. This stage typically takes about a week or two. Some people may experience some redness or tenderness for a short time after the crust falls off.

The entire outbreak cycle for cold sores usually takes about 7 to 14 days. However, the exact length of time can vary from person to person. Cold sores can also appear in different locations around the mouth and lip. While they most commonly appear on the border of the lip, they can also develop on the inside of the mouth, chin, nose, or cheeks. In rare cases, they can even spread to the eyes (ocular herpes) or fingers (herpetic whitlow).

How are Cold Sores Contracted?

Cold sores are very contagious and can be contracted through close contact with someone infected with the herpes simplex virus type 1 (HSV-1).

Direct contact is the most common way to spread cold sores. It can happen through kissing, sharing utensils, drinking glasses, or any other object that comes into contact with the saliva or blisters of someone with a cold sore.

Skin-to-skin contact and secondary contact via means such as sharing towels, washcloths, razors, or other personal items with someone who has a cold sore can also spread the virus. Although less common, cold sores can be spread through oral sex with someone who has HSV-1.

Important to note:

• You can even spread the virus when you don’t have a visible cold sore. The virus can be shed from the skin around the mouth even when there are no blisters present.
• Children are especially susceptible to contracting cold sores since their immune systems are still developing. 

Once a person is exposed to the cold sore virus, they have it for life. The virus is usually contracted during childhood, and is often passed between parents and children. In fact, by the age of 14, over 70% of children are infected by Herpes simplex virus-1. Some people may be “asymptomatic” which means they carry the virus but do not experience its symptoms.

How Do You Prevent Cold Sores?

Unfortunately, there is no guaranteed way to prevent cold sores completely since the virus that causes them, herpes simplex virus type 1 (HSV-1), stays dormant in your nerve cells for life. However, there are several steps you can take to significantly reduce your risk of outbreaks. 

Avoid close contact with infected individuals. This means avoiding kissing, sharing utensils, or any objects that could come into contact with the saliva or blisters of someone with a cold sore. Be especially mindful during times when they have a visible outbreak.

Maintain strong hygiene. Frequent handwashing is crucial, especially after touching your mouth or a cold sore (if you have one). This helps prevent spreading the virus to other parts of your body or to others.

Protect yourself from the sun. Sun exposure can trigger outbreaks, so protect your lips with a lip balm that contains SPF. Wearing hats and staying in the shade during peak sun hours are additional sun safety measures. Additionally, keep your lips moisturized. Dry, chapped lips can be more susceptible to outbreaks. Use a lip balm or petroleum jelly to keep your lips hydrated.

Manage stress. Stress can weaken your immune system, making you more susceptible to outbreaks. Practice relaxation techniques like meditation or deep breathing to keep stress levels in check.

Prioritize sleep. Aim for 7-8 hours of sleep each night. Adequate sleep strengthens your immune system, making it better equipped to fight off the virus.

Consider Antiviral Medication. In some cases, your doctor might recommend daily antiviral medication to suppress the virus and significantly reduce outbreaks, especially if you experience frequent or severe outbreaks.

How Do You Treat Cold Sores?

There is no cure for cold sores, but there are effective treatments that can shorten the healing time and alleviate symptoms. Here’s a breakdown of the different approaches:

Over-the-counter medications:

• Antiviral creams or ointments: These are topical medications applied directly to the cold sore. Common active ingredients include docosanol (Abreva) and penciclovir (Denavir). They are most effective when used at the first sign of an outbreak, during the tingling or itching stage, to help shorten the duration and severity of the outbreak.
• Pain relievers: Over-the-counter pain relievers like acetaminophen (Tylenol) or ibuprofen (Advil) can help manage any discomfort associated with cold sores.
• Lip balm: Using a lip balm or petroleum jelly can help keep lips moist and prevent chapping, which can worsen cold sores. Look for a lip balm with SPF to protect your lips from the sun, a known trigger for outbreaks.

Home remedies:

• Cold compresses: Applying a cool, damp compress to the affected area for short periods can help reduce swelling and discomfort.
• Zinc supplements: While research is ongoing, some studies suggest that taking zinc supplements regularly may reduce the frequency and severity of cold sores. However, it’s important to consult with your doctor before taking any supplements.

Commonly Prescribed Medications for Cold Sores

Oral antiviral medications may be prescribed by your doctor. These medications include acyclovir (Zovirax), famciclovir (Famvir), or valacyclovir (Valtrex). They are typically taken several times a day for a few days and can be more effective than topical creams, especially for frequent or severe outbreaks. These medications work by targeting and interrupting the herpes simplex virus type 1 (HSV-1) at a cellular level to shorten the duration and severity of cold sores.