Questions? Call us at 800-810-7790
Nov 16, 2023

Skin Health

Cold Sores: Causes, Prevention, and Treatment

What are cold sores?

Cold sores, also commonly referred to as herpes labialis, are small, painful, fluid-filled blisters or sores. These typically appear on or around the lips. They can also occur on the face or inside the mouth.

What causes cold sores?

Cold sores are the result of an infection by the herpes simplex virus, predominantly herpes simplex virus type 1 (HSV-1). It’s estimated that HSV-1 infection affects more than half of the population in the United States.

Not everyone infected with HSV-1 will develop symptoms. Some may carry the virus without ever having cold sores, while others may experience outbreaks.

This virus is very contagious. If a person has visible as cold sores on the mouth or lips, the virus can be transmitted to another person through oral contact. This includes kissing, sharing personal items such as utensils or drinks, or oral sex.

Infection of genital area: Traditionally, HSV-2 is associated with genital herpes. However, HSV-1 can also cause genital herpes through oral-genital contact. This infection will present similar symptoms to genital herpes caused by HSV-2, although HSV-1 genital infections are often less severe and less frequent in their recurrence.

What triggers cold sores?

Cold sores, caused by the herpes simplex virus, can be triggered by various factors. These triggers vary from person to person, but common ones include:

  • Emotional stress can be a common trigger for cold sore outbreaks, as stress may weaken your immune system, making it easier for the herpes virus to reactivate.
  • A weakened immune system from having a fever, cold, the flu, or other infections can increase your risk of experiencing a cold-sore outbreak.
  • Fatigue, lack of sleep, and exhaustion can weaken your immune system, making it easier for the virus to reactivate.
  • Hormonal fluctuations, such as those that occur during menstruation, pregnancy, or menopause, can lead to cold sore reactivation in some.
  • Physical injury to your lips or facial area can trigger cold sores.
  • Certain dental procedures that stress or irritate your lips may lead to cold sores.

What are the signs and symptoms of a cold sore?

Your first outbreak usually begins with a tingling, itching, or burning sensation around your lips or mouth, and some may even develop swollen lymph nodes that can last throughout their outbreak. This initial period is known as the prodromal stage and can last for a few hours or a day before visible symptoms appear.

Some common signs and symptoms of cold sores may include the following:

  • Tingling/itching
  • Fever
  • Blister forming and oozing: Blisters may appear on or around your lips, or inside your mouth. They may break open, releasing a clear fluid. The sores then ulcerate, forming painful, open lesions.
  • Crusting: As the cold sore starts to heal, it develops a yellow or brown crust or scab.
  • Pain
  • Swelling/redness
  • Healing: Over the course of about 7-14 days, your cold sore will gradually heal. The scabs will fall off, and new skin will form.

Cold sores are highly contagious, especially in the first 48 hours after they appear. The initial outbreak of a cold sore can last up to 20 days following the initial exposure to the herpes virus. These sores generally last several days, and healing can take 2 to 3 weeks for the blisters to completely resolve.

It's important to note that the herpes virus can become dormant in your body after the first infection. However, it can reactivate periodically, causing recurrent outbreaks. Triggers for these outbreaks include stress, sunlight exposure, and hormonal changes.

In recurrent outbreaks, cold sores usually appear in the same location as before but are typically less severe than the initial outbreak.

Is there a cure for cold sores?

There is no cure for cold sores, as they are caused by the lifelong presence of the herpes simplex virus in the body. However, their impact can be lessened with antiviral medications.

To prevent spreading the virus, avoid direct physical contact with cold sores during an outbreak. Prevention also involves avoiding known triggers, practicing good hygiene, and possibly using medications to decrease outbreak frequency. These steps won't completely prevent cold sores but can help manage and reduce their occurrence.

What are the treatment options for a cold sore?

Treatment should start at the first sign of tingling or discomfort around the mouth, before a sore is visible. Common treatment options include:

Over-the-Counter (OTC) Medications
  • Topical Creams/Ointments: OTC creams like docosanol (Abreva) can reduce the severity and duration of cold sores if applied early. L-lysine ointment may alleviate symptoms within 4 days.
  • Lip Balms: Some contain sunscreen to protect lips from UV exposure, a known outbreak trigger.
  • Pain Relievers: Non-prescription pain relievers can ease discomfort and fever associated with cold sores.
Prescription Medications
  • Antiviral Medications: Acyclovir (Zovirax), valacyclovir (Valtrex), and famciclovir are common choices. Available as topical creams or oral tablets, they're most effective when taken at the onset of an outbreak.

The choice between OTC and prescription medications depends on the frequency and severity of your cold sores. Consult with a doctor to determine the best treatment plan for you.

Speak with your doctor

It’s important to talk with your doctor about cold sores. Especially if you have recurring cold sore outbreaks, it's a good idea to have a discussion with your healthcare provider regarding available preventive medication choices.

Seeking guidance ensures you receive the right diagnosis and treatment, helps you manage and prevent future outbreaks, and addresses any potential complications or underlying health concerns.

Shop for Medications and Products Discussed in this Article

Related posts


What Causes Acne?

Choosing the Right Corticosteroid for Your Eczema