The herpes simplex virus, Type 1 (HSV-1), causes cold sores. This is not the virus that causes genital herpes, which is HSV-2. As many as four out of five Canadians are likely infected with the herpes simplex virus. Initial infection usually occurs during childhood. The virus stays inactive in the body until it is triggered later in life. Not everyone infected with the virus will get cold sores. About 20 to 40 per cent of those infected have problems with cold sores that keep returning.
A number of triggers can cause cold sores. The lesions get their name because certain viral infections, such as the cold or flu, can cause them to appear. Since fever is a trigger too, cold sores are also called fever blisters.
Dry lips, menstruation, fatigue or stress, food allergy, windburn, and physical injury to the lips may all trigger cold sores. Exposure to UV rays in intense sunlight may also be related. Frequently applying a sunscreen with SPF 15 or greater on the lips while in the sun may help prevent outbreaks. Certain chronic diseases, such as diabetes or an overactive thyroid gland, can also cause cold sores.
Triggers are not the same for everyone. A diary of unusual events can be used as a tool in identifying and avoiding potential causes.
Cold sores may begin with tingling, itching, or burning on or near the lips. The area may also be red. This prodromal (early) stage can last up to 24 hours. Ideally, this is when you should treat the area with antiviral medications.
Next, fluid-filled blisters appear and eventually burst. This stage is the most contagious and painful. The fluid is full of virus, which can infect another area on the body or another person. The eyes and genital area should not be touched unless hands have been properly washed. Avoid sharing food, utensils, razors, or cosmetics, as well as kissing and other intimate activities.
Painkillers such as acetaminophen, ASA, or ibuprofen can help with the pain. Keep in mind that children under 18 years of age should not take ASA unless directed to by a doctor.
A hard crust then forms over the cold sore, leading to a scab. Gradually, normal skin grows back. If a lesion appears at the same place every time, a scar may form. Cold sore outbreaks usually last up to 14 days. See a doctor if your cold sore lasts beyond two weeks.
Occasionally, the lesion becomes infected after the blisters burst. If there is yellow pus beneath the crust, then the area may be infected with bacteria. Application of an antibiotic ointment to the infected area is helpful. If the infection does not get better in several days, see your doctor.
Many available over-the-counter (OTC) remedies only help lessen the discomfort of cold sores. They do not prevent re-infection or spread of the virus, or shorten healing time. OTC remedies usually include a combination of skin protectants and local anesthetics (painkillers).
Skin protectants physically protect the cold sore and keep the area moist. This prevents further drying and cracking, which may lead to more pain and possible infection with bacteria. Skin protectants include allantoin, cocoa butter, dimethicone, glycerin, petrolatum, and shark liver oil. Lip balms are included in this category.
Local anesthetics can be applied to relieve discomfort associated with cold sores. (The most painful time is usually after a blister has just burst.) Pain medications include benzocaine, lidocaine, tetracaine, camphor, menthol, phenol, benzyl alcohol, and resorcinol. Cold sore Anbesol™, Viractin™, Zilactin™, Blistex™ Kank-A™ liquid, Blistex™ Lip Ointment, and Blistex™ Lip Medex™ all contain one or more of these ingredients.
Zinc and heparin may also be found in some OTC cold sore products. In some studies, zinc has been found to disrupt the reproduction of viruses. However, zinc sulfate (the form of zinc found in OTC products) can sometimes cause more drying. The cold sore may crack, leading to pain and possible infection.
Heparin attaches itself to the cold sore virus before it can attack human cells. However, more evidence is needed to know whether both zinc and heparin really work well for cold sores.
Lipactin™ contains both of these ingredients. It is approved by Health Canada for the treatment of cold sore symptoms. Studies by the manufacturer show that, applied early enough, Lipactin™ can reduce the duration of pain and increase the rate of healing. However, the number of people treated in the studies is quite small. More research may be needed to further prove its effectiveness.
Docosanol (Abreva™) is a newer cream available for cold sores. It is the first OTC product approved for the treatment of cold sores and fever blisters. Docosanol works by stopping HSV-1 from entering cells. Studies have shown that it speeds healing time by one day compared to not using any treatment at all. Docosanol may also lessen the pain, burning, itching, and discomfort of cold sores.
In 34 per cent of people, docosanol can stop the cold sore from progressing to the blister stage. This only works if it is applied at first sign of cold sore symptoms. Apply it five times daily to the affected area, using a finger cot or rubber glove, until the sore completely heals. Docosanol is well-tolerated, with the most common side effects being headache and a stinging sensation when applied. Sometimes it can irritate the application site, but this is rare.
If a person has six or more cold sore outbreaks per year, prescription medications will usually be prescribed by a doctor. These prescription products are antivirals, medications that interfere with the reproduction of viruses in our cells. They should be used at the very first sign of an outbreak.
Viruses are not able to reproduce themselves. They must invade living cells, such as human cells, in order to reproduce. Viruses usually first attach to a host cell, then enter the cell. Once inside, they usually release their own genetic material. The host cell is forced to use the genetic material of the virus, to make more virus.
Sometimes, host cells rupture to allow the virus to leave, causing the host cell to die. With HSV-1, the virus leaves genetic material in the host cell, and remains inactive. The virus grows again when the host cell is disturbed.
Antiviral medications usually interfere with one of many steps in this process in order to block the reproduction of viruses.
When medically prescribed, the following antiviral medications can be taken by mouth to treat cold sores.
Several herbal remedies may be effective in treating or preventing cold sores. As even natural medicines can cause reactions, they must be used according to recommended doses, like all medication.
A lip balm containing one per cent lemon balm may be effective for cold sores. It appears to heal cold sores faster, prevent the spread of infection, and reduce the symptoms of returning outbreaks. Apply it two to four times daily at the first sign of an outbreak, and continue a few days after the cold sore has healed. However, larger clinical studies are needed to prove that lemon balm is truly effective.
Sage and rhubarb
Applying a cream with both sage and rhubarb may be effective for faster healing of cold sores. With acyclovir cream, the cold sore takes 6.3 days to heal. With the combination sage and rhubarb cream, healing occurs in 7.2 days. The sage and rhubarb cream should be applied right away when an outbreak is suspected. Apply it every two to four hours while awake, for ten to fourteen days. More evidence from larger research studies is necessary to show that this combination is effective.
Lysine may help reduce the number of times that cold sores return. It may also speed healing time and decrease the severity of cold sores. Usually, 1000 milligrams are taken by mouth once daily for twelve months, or 500 milligrams three times daily for six months. Those with kidney disease or osteoporosis should not take lysine. Taken orally, it can also interact with calcium supplements. Lysine may also help when applied directly to the cold sore. As with other herbal remedies for cold sores, more research is needed to prove that lysine is effective.
Tannic acid is not effective for cold sores and may dry the skin, resulting in a bacterial infection.
Cold sores are very common, and looking after them properly is important to healing. Recognize symptoms early, and start treatment right away. With the right knowledge and medicines, cold sores can heal faster and hurt less. Steps can also be taken to prevent future cold sores. Speak to your pharmacist or doctor to decide how to treat your cold sore outbreaks.