Cold sores are caused by infection with one of two types of the herpes simplex virus. They usually form on the borders of the lips, known as the vermilion. But they can also occur elsewhere, such as on or inside the nose, on the chin and inside the mouth, including on the tongue. Cold sores are not serious and usually resolve without scarring within 10 to 14 days. Applying coffee to cold sores might offer modest beneficial effects on the severity or duration of symptoms.
Relationship
In the June 2008 issue of "Food and Chemical Toxicology," a team of Japanese researchers, led by Hirotoshi Utsunomiya, D.V.M., Ph.D., reported that a weak solution of coffee -- one-fifth the usual drinking strength -- inhibited the growth of the herpes simplex virus in test tubes and prevented newly formed viruses from infecting new cells. Although researchers have known since the 1980s that caffeine inhibits the growth of herpes simplex, Utsunomiya's study suggests that coffee also contains other, undetermined compounds that confer benefits to those who suffer from cold sores.
Risks
Hot coffee can cause burns that actually make cold sores worse. This is because cold sores lack the protective outer layer of normal skin, so they are more sensitive to tissue damage. To avoid additional tissue damage, patients should consume coffee that is cold or room-temperature. Regardless of temperature, there is no guarantee that coffee will have a positive effect on cold sores. Utsunomiya's results were obtained in test tubes, and substances that work well in test tubes don't always work well in people. As of October 2010, the National Library of Medicine lists no studies on oral or topical coffee in people with cold sores.
Benefits
Coffee might confer a modest benefit on the severity or duration of cold sore symptoms. In Utsunomiya's study, coffee came into direct contact with cells infected by the herpes simplex virus, just as it does when people drink it in real life. Despite the lack of studies in people, the similarity between Utsunomiya's study design and natural settings of coffee consumption increases the likelihood that they will apply.
Considerations
Coffee is addictive and may lead to fast heart rate, frequent urination, nausea, vomiting, anxiety, agitation, tremors and insomnia, especially in people who do not consume it regularly. Most of these effects are a response to the caffeine content of coffee. However, caffeine confers at least some of the beneficial properties of coffee seen in Utsunomiya's study, so switching to decaffeinated coffee would not help. In addition, Utsunomiya's study evaluated only weak solutions of pure coffee. Cream and other common coffee additives might render it ineffective.
Alternatives
In the 2007 edition of "Integrative Medicine," University of Wisconsin professor David Rakel stresses the importance of rest, exercise, stress management and consuming a balanced diet for the prevention of cold sore outbreaks. Rakel also discusses other compounds that may offer therapeutic benefits to people with cold sores, including vitamin C, zinc, lemon balm, licorice root and tea. None of these approaches, however, replace conventional medical treatment. People with severe, recurrent or prolonged -- that is, longer than two weeks -- cold sores should see a doctor.
References
- "Archives of Internal Medicine"; The Treatment of Herpes Simplex Infections; Christina Cernik, M.D., et al.; June 9, 2008
- "Food and Chemical Toxicology"; Antiviral Activities of Coffee Extracts In Vitro; Hirotoshi Utsunomiya, D.V.M., Ph.D., et al.; June 2008
- "Integrative Medicine"; David Rakel, M.D.; 2007
- MedlinePlus: Caffeine in the Diet
