What causes them?

One day you’re going about your normal activities when you notice that your lips seem to have a tingling, itching sensation. It’s not really bothersome, so you don’t think much about it. A few days later, you notice that some blisters appear in the same area. What caused them to occur? How can you get rid of them? Can you prevent them from coming back?


Cold sores (or fever blisters) are tiny, fluid-filled blisters that form on and around your lips, often they’re grouped in patches. They’re caused by certain strains of the herpes simplex virus (HSV), usually HSV-1. HSV-2 usually results in genital herpes. However, it’s important to note that either type can be spread to the face or genitals through close contact, like kissing or oral sex. The viruses can also be spread through the sharing of eating utensils, razors, or towels.

Once you’ve had one episode of a herpes infection, the virus lies dormant in the nerve cells in your skin and can emerge at another time in the same place as before. Recurrences can be triggered by many things, with the most common being another infection or fever (hence the name cold sores or fever blisters), hormonal changes (ex. those related to menstruation), stress, fatigue, exposure to sunlight and wind, changes in your immune system, or an injury to the skin.

Symptoms of cold sores usually follow several stages. The first typically involves tingling and itching around your lips for a day or so before small, hard, painful blisters appear. The small fluid-filled blisters erupt along the edge of your lips. They can also appear around your nose or cheeks or inside your mouth. Sometimes, the tiny blisters merge and then burst, leaving shallow open sores that ooze and crust over. Sores last several days, and blisters take two to three weeks to heal completely. You’re most contagious when you have oozing blisters, but you can still spread the virus even if you don’t have any blisters. In fact, many people who are infected with the virus never have symptoms but can still transmit the virus to others. Symptoms vary depending on if this is your first outbreak or a recurrence. If this is your initial outbreak, signs start about 20 days after you were first exposed, and you might also experience fever, painful gums, sore throat, headache, muscle aches, and swollen lymph nodes. Recurrences typically appear at the same spot each time and tend to be less severe.

Almost everyone is at risk of cold sores. However, some individuals are more likely to have complications, such as those with HIV/AIDS or atopic dermatitis (eczema) and those undergoing chemotherapy or taking anti-rejection drugs for organ transplants. Complications can include problems in other areas of the body. Both types of herpes can be spread to the fingers (often called herpes whitlow). Sometimes, the virus can cause an eye infection. Repeated infections can result in scarring and injury, leading to vision problems or loss. If you have atopic dermatitis, you’re at higher risk of cold sores spreading across your body. In some cases, this can become a medical emergency.

TreatmentFast Facts - Fragile X Syndrome

In most cases, cold sores clear up without treatment in two to four weeks. The over-the-counter ointment docosanol may shorten the healing time. Apply it to the affected skin as directed on the package at the first sign of symptoms. Be sure to use a cotton-tipped swab to put medicine on to help prevent the spread of the sores to other parts of your body. You can also try other over-the-counter preparations that contain a drying agent, such as alcohol. Taking over-the-counter pain relievers can be beneficial if you have a fever or the cold sore is painful. Creams with lidocaine or benzocaine may offer some pain relief too. Applying a cold, damp cloth may reduce redness, help remove crusting and promote healing. Some individuals find that a warm compress helps to ease the pain.

Several types of prescription antiviral medications, such as acyclovir, valacyclovir, famciclovir, and penciclovir, can speed the healing process. Some of these are pills, and others are creams. Typically, the pills work better than the creams. Some antiviral drugs can be given as an injection for very severe infections.


If you develop cold sores more than nine times a year or if you’re at high risk of serious complications, your doctor may prescribe an antiviral medication for you to take regularly. If sunlight seems to trigger your recurrences, it’s essential to protect your lips from the sun with a zinc oxide cream or lip balm with sunblock. If your lips become dry, apply a moisturizing cream. If your cold sores are triggered by stress, you might want to try relaxation techniques, like deep-breathing exercises and meditation. To help avoid spreading cold sores to other people or other parts of your body, there are precautions you can take. Make sure to avoid kissing and skin contact with people while blisters are present. Also, avoid sharing things like utensils, towels, lip balm, and other personal items. Wash your hands frequently and thoroughly before touching yourself and other people, especially babies.

While cold sores are annoying to have, they will get better! If you have any questions or concerns about cold sores, please speak with your doctor. If you would like more information, please visit the American Academy of Dermatology Association’s Cold Sore page at https://www.aad.org/public/diseases/a-z/cold-sores-overview