Dear Doctor Column, February 21, 2005
Seeking Relief From Fever Blisters
Question:
What causes cold sores? Are they infectious and what treatments are available?
Answer:
Cold sores or fever blisters, known medically as herpes labialis, affect an estimated 1 of 5 Americans. Cold sores most often afflict adolescents and young adults but can occur at any age; outbreaks decrease after age 35. Most sufferers experience 1 to 3 attacks annually. Type 1 herpes simplex virus, which can be spread through direct contact, such as kissing or by sharing utensils or towels, causes the familiar facial blisters, generally appearing around the mouth and on the lips. They also can occur on the nostrils, chin, or cheeks; type 2 herpes simplex virus is responsible for most cases of genital herpes.
After the initial infection, the virus remains in the body, lying dormant in the nerves. Re-activation of the virus and development of the lesions is often triggered by stress, menstruation, colds, fever, or exposure to the sun's ultraviolet rays. Cold sores usually begin with tingling or itching, leading to small blisters that eventually rupture and then begin to dry, forming a thin, yellowish crust. Without treatment, cold sores usually heal within 1 to 2 weeks.
The herpes virus can be transmitted even when blisters are not present, but the greatest risk of infection is from the time the blister appears until it has completely crusted over.
Treatments
Penciclovir 1% cream (Denavir) is approved by the Food and Drug Administration for recurrent fever blisters. Requiring a prescription, it is applied every 2 hours to the site for 4 days. Studies show that starting treatment within 1 hour of an outbreak reduced the time to healing by 2 days and reduced symptoms. The earlier penciclovir is started, the better the benefits, but improvement was still found when the medication was started even after sores developed. Other antiviral drugs, such as acyclovir, famciclovir and valacyclovir, have shown some benefit, as well.
An over-the-counter medicine called Abreva (generic name docosanol) may help cold sores heal faster and reduce the symptoms associated with them. Studies show Abreva can help cold sores heal 1 day sooner than when no drug is used. When applied at the earliest stages of an outbreak, Abreva may help prevent a blister from forming.
Other over-the-counter products can help relieve the discomfort of cold sores, but they do not help them go away faster. To relieve dryness and help keep the sores soft, use products containing the ingredients allantoin, petrolatum, or cocoa butter. Examples of these products include Blistex lip ointment and Carmex ointment.
For pain relief, try products that contain local anesthetics. Anbesol cold sore ointment contains benzocaine, and Zilactin ointment contains benzyl alcohol to relieve pain. You also can use pain relievers such as acetaminophen or ibuprofen. If a cold sore becomes infected, apply an antibiotic ointment, such as Polysporin, three to four times a day. If sun exposure tends to reactivate your cold sores, use a lip sunscreen.
Although fever blisters cannot be prevented, there are things you can do to reduce occurrences:
- Do not squeeze, pinch, or pick at any blister
- Avoid kissing and other mucous membrane contact while blisters are present.
- Wash hands carefully before touching another person.
- Use sunblock on lips before prolonged exposure to the sun.
For more information, visit the American Dental Association Web site, or the Federal Citizen Information Center.