Cold Sores (Fever Blisters, Herpes Simplex)

Cold sores appear as small, painful blisters around the mouth. They occur usually in groups, with a red ring surrounding each blister, and last for one to three weeks. During this period, the sores fill with fluid, and then crust over, dry up, and disappear.

The Type 1 herpes simplex virus causes most cold sores, although some cases are due to the Type 2 virus that is usually responsible for genital herpes. The herpes virus is highly contagious and, once acquired, it may lie dormant in the body for years. Some people experience recurrent outbreaks throughout their lives. For most persons, though, recurrences stop within a few years of the first outbreak.

A fever, exposure to the sun, or physical or emotional stress can bring on an attack from a dormant virus. Even such minor demands on the immune system as fighting a cold or an intestinal infection can result in a flare-up of cold sores. Women have a higher risk of developing them during their menstrual periods and in the premenstrual phase.

Diagnostic Studies and Procedures

Cold sores almost always are diagnosed on the basis of symptoms and the characteristic appearance of the blisters. If a secondary bacterial infection develops, a laboratory culture may be ordered.

Medical Treatments

In most instances, cold sores heal themselves without any medical treatment. An exception would be an eruption that occurs in someone who has a compromised immune system or an infection near or in the eyes. In the latter case, prompt treatment with antiviral eyedrops or ointment, usually vidarabine (Vira-A), trifluridine (Virop-tic), or idoxuridine (Herplex Liquifilm and Stoxil) is needed to prevent eye damage. The medication should be applied to the eyes several times a day.

Extensive cold sores in the mouth area may be treated with acyclovir (Zovirax), an antiviral agent. An antibiotic ointment may also be prescribed if a bacterial infection develops.

Alternative Therapies

Herbal Medicine. Herbalists may prescribe echinacea tea, tablets, or tincture in order to stimulate the immune system against viral injections. A few drops of lavender oil applied to the sore may promote healing.

Homeopathy. To speed healing, practitioners suggest applying a solution made with one part calendula tincture and three parts water to the sores after they have opened. Other homeopathic remedies include rhustoxkodendron, a general anti-infective, and sepia. Oozing blisters may be treated with topical nairum murialicum or graphites.

Naturopathy and Nutrition Therapy. High doses of vitamin C are said to be effective against cold sores, although there is no definitive scientific proof for this belief. An amino acid called L-lystne is also used sometimes by persons who have recurrent attacks of cold sores. It comes in pills or in a cream to be applied to the sores.

Other natural or nutritional remedies are supplements of vitamin B complex, lozenges of zinc gluconate, acidophilus pills or yogurt containing acidophilus cultures, and garlic capsules.

Self-Treatment

Minor pain can be relieved with acetaminophen, aspirin, or ibuprofen. Remember, however, that aspirin should not be given to anyone under the age of 18 years during a viral infection because of an increased risk of Reye's syndrome, a potentially life-threatening disorder.

Applying an ice cube to the lesion for an hour or so when it first appears can help speed healing. Dipping a cotton ball in cold milk and applying it to the sore has the same effect. Even better, use one of these techniques at the first sign of a cold sore, which may be a stinging, tingling, or itching sensation on a part of the mouth where outbreaks are likely to occur.

Once a blister develops, soothe it by drinking cool liquids, sucking frozen juice bars, or applying petroleum salve or over-the-counter anesthetics. Salves are particularly helpful for softening scabs that form as cold sores heal. Avoid irritating salty and acidic foods until the lesion heals completely. Don't try to mask a cold sore with makeup, as this action can make it worse.

Because cold sores are very contagious, you should avoid kissing and other skin contact with a person who has one. Be particularly careful about sexual contact with anyone who has a cold sore; the herpes virus can be transmitted through oral-genital contact, resulting in genital herpes.

Also, wash your hands frequently to avoid spreading the virus to others, and avoid sharing glasses, cups, eating utensils, towels, and washcloths.

Other Causes of Skin Blisters

Cold sores are sometimes confused with impetigo, a skin infection caused by a bacterium that produces a red rash with many small blisters. A canker sore on the lips may feel like a cold sore, but it has a different appearance. Chickenpox and shingles, which are also caused by a virus in the herpes family, produce tiny, blister-like lesions that may appear on the face.