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Health Information | 11/08/2022

The Cold Truth About Cold Sores

By  Dr. Sergio Ramoa
Cold sores are incredibly common, and many people experience them from time to time. However, there’s a lot of stigma around cold sores, which can lead to confusion and embarrassment when you get one. So, what are cold sores exactly? And how can you treat them?

Cold sores appear as a cluster of small, fluid-filled blisters that usually form on the edges of your lips or mouth. They’re caused by the herpes simplex virus (HSV) and are spread through close personal contact, such as kissing or sharing a drink.

There are two types of HSV: HSV-1, which is usually the cause of cold sores, and HSV-2, which is usually the cause of genital herpes. For some, HSV lies dormant in your cells and comes back in the form of cold sores.


Once someone is exposed to HSV, they may experience cold sore symptoms roughly two to three weeks later. When someone develops a cold sore, they might experience the following:
  • Tingling and itching, with a hard, painful spot appearing – this is the best time to start treatment.
  • Small, fluid-filled blisters that erupt, usually on the edge of your lips, sometimes the nose, cheeks, or inside of the mouth.
  • Oozing and crusting when blisters burst
  • Scabbing
If it’s your first time getting a cold sore, you might also experience fever, painful gums, sore throat, headache, swollen lymph nodes, pain inside your mouth, pain when swallowing, and upset stomach.

After your first cold sore, your body might build up antibodies, and it’s possible that you’ll never get a cold sore again. However, many people do experience repeated cold sores.

Recurring cold sores typically happen in the same spot each time. A recurrence can be caused by the following:
  • Viral infection or fever
  • Hormonal changes, like menstruation
  • Stress
  • Fatigue
  • Exposure to sunlight or wind
  • Changes to the immune system
  • Injury to the skin
  • Allergies
  • Dental work or cosmetic surgery
  • Medications that weaken the immune system

Diagnosis and Treatment

Your provider can diagnose a cold sore just by looking at it, or they might swab the blister and test the fluid for HSV. An antibody blood test can also determine if you have HSV, but this is usually not necessary when you are dealing with an active outbreak, as antibodies can take up to 2 weeks to develop.

While HSV and cold sores can’t be cured, they are easily treated, and proper care can reduce the frequency and severity of any future outbreaks.

If you think you have a cold sore, speak with your provider about the following:
  • Anti-viral medications that can speed up the healing process
  • Over-the-counter cold sore remedies, particularly those containing alcohol to dry out the blister
  • SPF lip balm to protect your lips and cold sore from the sun
  • Using a damp cold compress or icepack to reduce redness and crusting and a warm compress to reduce pain
  • Over-the-counter pain relievers, either in the form of a pill (like acetaminophen or ibuprofen) or a cream (like lidocaine or benzocaine) to reduce discomfort


While HSV is very common and nothing to be ashamed of, it’s important to take steps to prevent yourself from spreading it to others.

If you have an active outbreak, you should:
  • Avoid kissing, oral sex, and close skin contact if you (or your partner) have a cold sore
  • Avoid sharing personal items like utensils, lip balm, towels, razors, and toothbrushes
  • Avoid sharing drinks or food
  • Wash your hands often
  • Avoid touching, picking at, or popping the cold sores, as this can spread the virus to other parts of your body

Risk Factors and Complications

Some people have a higher risk for complications related to their cold sores. People with HIV/AIDS, eczema, undergoing chemotherapy, or taking anti-rejection drugs for organ transplants are at higher risk. If you fall under any of these categories, make sure to speak with your provider about how to treat cold sores.

Most complications are not life-threatening, but they can cause more severe illness. These include:
  • Eye infections, which could lead to vision problems or vision loss
  • Cold sores spreading across the body if you have eczema
  • Cold sores spreading to the fingers
  • Cold sores spreading to genitals
  • Meningitis or encephalitis. This is very rare but dangerous, especially in people with weakened immune systems.
While cold sores are inconvenient and painful, you shouldn’t feel embarrassed if you get one. Your Atrius Health provider can give you helpful advice on how to heal them sooner, ease any discomfort, and prevent them from coming back.

About The Author

Dr. Sergio Ramoa

Dr. Sergio Ramoa joined Atrius Health in 2021 and is a family medicine doctor practicing in internal medicine at Harvard Vanguard – Quincy. He attended medical school at Virginia Commonwealth University School of Medicine in Richmond, VA, and completed his residency at Jackson Memorial Hospital in Miami, FL. He is also board-certified by the American Board of Obesity Medicine and has a strong interest in helping his patients with weight management.

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