What are cold sores and how should I treat them?

Cold sores appear as an inflamed cluster of blisters around the lip, under the nose or on the chin. Itching, burning or pain can be experienced before the blisters develop (called a “prodrome”). The blisters form a yellowish crust over the course of a few days, which sometimes open to reveal shallow ulcers which then heal over.

The cause is the herpes simplex virus, usually type 1 (HSV-1), which is passed from person to person by saliva or skin contact. According to the World Health Organization, over two thirds of people under age 50 have been infected, though not all develop cold sores.

The virus travels to the root of a nerve and remains dormant. When the immune system is weakened, the virus re-activates and multiplies in an area of skin in the path of the nerve. This is why sores often recur in the same general area.

Cold sores are highly contagious from the time of first symptoms until they’re completely healed. The most contagious aspect is the fluid in the blister. To prevent being infected, be cautious about contact with someone who has a visible sore. Avoid sexual contact with them and don’t touch the area of their sore or share utensils or drinking glasses with the person.

To reduce sores’ frequency, support the immune system with healthy habits including adequate sleep, exercise and stress minimization. Significant sun exposure or the concentrated light energy in lasers can trigger cold sores, as can irritating cosmetic procedures such as chemical peels and microdermabrasion. Avoid using and reusing products like lip liner and lip balm once you’ve had a sore.

Without medication, it usually takes 7-10 days for a cold sore to completely heal. The fastest way to heal them is with antiviral medication, sold both in over-the-counter and prescription strengths as ointments and pills. Commonly used home remedies and supplements include L-Lysine, echinacea, eleuthero, zinc, bee products and aloe, but there is inconsistent scientific data to support their use. Over-the-counter pain medication such as ibuprofen or acetaminophen can be used for general pain relief.

See a physician if sores become extensive or last longer than a couple of weeks; this can be a sign of a more significantly compromised immune system. Concurrent development of a fever or becoming confused can very rarely be a sign of the herpes virus infecting the brain and must be treated by a physician. Any unusual rash on the body that accompanies mouth sores should also be evaluated by a physician; these types of hypersensitivity reactions may benefit from additional prescription medication to resolve more quickly.

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Sonia Batra, M.D., M.Sc., MPH is a practicing, board-certified dermatologist. She earned her medical degree with honors from Harvard, a master’s degree as a Rhodes Scholar at Oxford University and completed her internship and residency at Stanford University Medical Center. As a recurring co-host on The Doctors, she delivers cutting-edge medical, surgical and cosmetic skin care insights. Visit her at www.batraskincare.com.