Dear Mayo Clinic: I have had a few cold sore flare-ups over the past few months after years without getting any. What causes them to come back, and what's the best way to treat them?
A: Cold sores are caused by the herpes simplex virus. Once you're exposed to the virus, which is typically passed from skin-to-skin contact, it's present in your body for life. After the initial infection, the virus will travel to your nerves, where it remains dormant but may awaken periodically. Often, there's a trigger that causes the virus to wake up, which leads to the development of cold sores. There's no cure, but antiviral medications can help cold sores heal more quickly and may reduce how often they return.
A cold sore is a small, fluid-filled blister—or more often, a group of blisters—that typically develops on or around the lips. These blisters quickly dry out and form a scab. A day or two before an outbreak occurs, you may experience a burning, itching or tingling sensation on the area of skin where the sore eventually will appear.
Common triggers that can lead to cold sores include stress; illness, such as a cold or influenza; exposure to sunlight, wind or other elements; a cut or injury to the skin; changes in the immune system; and hormonal changes.
Most cold sores will heal on their own within a couple of weeks. If the discomfort bothers you, a nonprescription pain reliever such as acetaminophen or ibuprofen may help.
A cool compress or sucking on ice chips may minimize any burning or itch. You also may want to cut back on foods that can irritate a sore, including foods that are salty or spicy, as well as acidic foods, such as tomatoes and citrus fruits. Applying petroleum jelly to the sore and surrounding skin can reduce dryness and cracking.
To reduce the duration of cold sores and relieve symptoms, the nonprescription antiviral cream docosanol (Abreva) may be worth a try. Abreva is most effective if used when you first notice tingling or other early symptoms that indicate a cold sore is forming. However, the effect of the drug is limited, only reducing the duration of symptoms by a matter of hours.
If a cold sore persists for longer than two weeks or keeps returning, see your primary care provider or a dermatologist for an evaluation. He or she may recommend treatment with an antiviral medication in pill form. Oral antivirals may take one to two days off of the duration of an outbreak.
If you have eczema or a weakened immune system, you may be prone to more serious infections and complications, and should consult your health care provider. Also, see your provider for treatment if any cold sores develop near your eyes or at the tip of your nose.
To keep the virus from spreading, avoid kissing and other skin-to-skin contact with anyone else while you have a cold sore. Keep personal items, such as towels and lip balm, separate from other people in your household during the time you have a sore. Do not share utensils, cups or other dishes.
To protect your skin and reduce the likelihood of further flare-ups, use a lip balm that contains a broad-spectrum sunscreen. Stress-relieving techniques also may help reduce outbreaks.
©2019 Mayo Foundation for Medical Education and Research
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