Also indexed as: Fever Blisters, Herpes Simplex 1 Virus
Cold sores are painful fluid-filled blisters that form on the borders of the lips caused by
a herpes virus, most often the herpes simplex 1 virus.
Cold sores should not be confused with canker
sores, which are small ulcerations in the mouth. The blisters, which are contagious, later
break, ooze, and crust over before healing. Recurrences are common and can be triggered by
stress, sun exposure, illness, and menstruation.
Genital herpes infection (usually caused by herpes simplex 2) is a related condition and
potentially may be treated in much the same way as herpes simplex 1.
Checklist for Herpes
Simplex/Cold Sores
What are the symptoms of cold sores?
Cold sores may appear with colds, fevers, exposure to excessive sunlight, or menstrual
periods, as well as during periods of stress or illness. The sores usually disappear within
two weeks. Initially, there may be tingling or prickling at the site of the cold sores even
before they are visible (called the prodrome); afterward, the blisters often weep a clear
fluid and form a scab. If the infection is transmitted
to the eyes, it may lead to blindness.
Medical treatments
The over the counter topical agents docosanol (Abreva®) and allantoin
(Herpecin-L®), as well as camphor and phenol combinations (Campho-Phenique®), help
relieve pain and might promote healing of cold sores. Analgesics, such as aspirin (Bayer®, Ecotrin®, Bufferin®), ibuprofen (Motrin®, Advil®), and acetaminophen (Tylenol®), might provide some pain
relief.
Antiviral prescription medications such as topical acyclovir (Zovirax®), topical penciclovir
(Denavir®), or oral acyclovir (Zovirax®)
might reduce the duration of the sores.
Dietary changes that may be helpful
The herpes simplex virus has a high requirement for the
amino acid, arginine. On the other hand, the amino
acid, lysine, inhibits viral replication.1
Therefore, a diet that is low in arginine and high in lysine may help prevent or treat herpes
outbreaks. Several studies have shown that increasing lysine intake can reduce the recurrence
rate of cold sores.2 Although people with herpes simplex reportedly consume about
the same amount of arginine and lysine in their diet as do people without cold
sores,3 it is conceivable that adjusting the intake of these amino acids may be
beneficial. For that reason, many doctors advise people with cold sores to avoid foods with
high arginine-to-lysine ratios, such as nuts,
peanuts, and chocolate. Nonfat yogurt and other nonfat dairy can be a healthful way to
increase lysine intake.
Nutritional supplements that may be helpful
The amino acid,
lysine, has been reported to reduce the recurrence rate of herpes simplex infections in both preliminary4 5 and
double-blind trials.6 7 The amount used in these studies was usually 1
to 3 grams per day, although some people received as little as 312 mg per day. In one
double-blind trial, lysine supplementation (1,200 mg per day) failed to prevent recurrences
better than placebo.8 However, the results of that study may have been skewed by a
large number of dropouts in the placebo group who fared poorly but were not included in the
analysis.
When lysine has been used for acute outbreaks, the results have been mixed. In a
preliminary study, 390 mg of lysine taken at the first sign of a herpes outbreak resulted in
rapid resolution of the cold sores in all cases.9 However, in a double-blind study,
supplementing with 1 gram of lysine per day for five days did not increase the healing rate of
the cold sores.10
Vitamin C has been shown to inactivate herpes viruses
in the test tube.11 In one study, people with herpes infections received either a
placebo or 200 mg of vitamin C plus 200 mg of flavonoids,
each taken three to five times per day. Compared with the placebo, vitamin C and flavonoids
reduced the duration of symptoms by 57%.12
Zinc preparations have been shown to inhibit the replication
of herpes simplex in the test tube.13 In one study, people with recurrent herpes
simplex infections applied a zinc sulfate solution daily to the sores. After healing occurred,
the frequency of applications was reduced to once a week for a month, then to twice a month.
During an observation period of 16 to 23 months, none of these people experienced a recurrence
of their cold sores.14
Zinc oxide, the only commercially available form of zinc for topical application, is
probably ineffective as a treatment for herpes simplex.15 Other forms of topical
zinc can be obtained by prescription, through a compounding pharmacist. However, because an
excessive concentration of zinc may cause skin irritation, topical zinc should be used only
with the supervision of a doctor knowledgeable in its use.
In a preliminary trial, a piece of cotton saturated with
vitamin E oil was applied to newly erupted cold sores and held in place for 15 minutes.
The first application was performed in the dentist’s office. Participants were
instructed to repeat the procedure every three hours for the rest of that day, and then three
times daily for two more days. In nearly all cases, pain disappeared in less than eight hours.
Application of vitamin E oil appeared to accelerate healing of the cold sores.16
Similar results were reported in another study.17
Application of an ointment containing propolis, the
resin collected by bees from trees, has been shown to relieve genital herpes more effectively
than topical acyclovir.18 It is likely
that this treatment might also benefit people with cold sores, although this has not been
tested. Propolis ointment should be applied four times per day.
Boric acid has antiviral activity. In a double-blind
trial, topical application of an ointment containing boric acid (in the form of sodium borate)
shortened the duration of cold sores by about one-third.19 However, concerns about
potential toxicity have led some doctors to avoid the use of boric acid for this purpose.
A preliminary study found that people with recurrent cold sores have lower iron stores than healthy people.20 This may mean that
correcting an iron deficiency might help prevent herpes outbreaks, but more research is
necessary. Most people should not take iron supplements unless they have an iron deficiency,
confirmed by a blood test.
Are there any side effects or interactions?
Refer to the individual supplement for information about any side effects or interactions.
Herbs that may be helpful
Lemon balm has antiviral properties. A cream
containing an extract of lemon balm has been shown in double-blind trials to speed the healing
of cold sores.21 In one double-blind trial, topical application of a 1% 70:1
extract of lemon-balm leaf cream, four times daily for five days, led to significantly fewer
symptoms and fewer blisters than experienced by those using a placebo cream.22 In
most studies, the lemon-balm cream was applied two to four times per day for five to ten
days.
The proanthocyanidins in witch hazel have been shown to exert significant antiviral
activity against herpes simplex 1 in the test tube.23 In a double-blind trial,
people with acute cold sore outbreaks applied a topical cream containing 2% witch hazel bark
extract or placebo six times a day for three to eight days.24 By the end of the
eighth day, those using the witch-hazel cream had a pronounced and statistically significant
reduction in the size and spread of the inflammation when compared to the placebo group.
Licorice in the form of a cream or gel may be applied
directly to herpes sores three to four times per day. Licorice extracts containing
glycyrrhizin or glycyrrhetinic acid should be used, as these are the constituents in licorice
most likely to provide activity against the herpes simplex virus. There are no controlled
trials demonstrating the effectiveness of this treatment, but a cream containing a synthetic
version of glycyrrhetinic acid (carbenoxolone) was reported to speed healing time and reduce
pain in people with herpes simplex.25
In traditional herbal medicine, tinctures of various herbs, including chaparral, St. John’s
wort, goldenseal,
myrrh, and echinacea, have been applied topically to
herpes outbreaks in order to promote healing.
An extract from elderberry leaves, combined with St.
John’s wort and soapwort (Saponaria officinalis), has been found to inhibit the
herpes simplex virus in the test tube.26 However, the effect of these herbs on cold
sores has not been studied.
Are there any side effects or interactions?
Refer to the individual herb for information about any side effects or interactions.
References
1. Tankersley RW Jr. Amino acid requirements of herpes simplex virus in
human cells. J Bacteriol 1964;87:609–13.
2. Flodin NW. The metabolic roles, pharmacology, and toxicology of
lysine. J Am Coll Nutr 1997;16:7–21 [review].
3. Algert SJ, Stubblefield NE, Grasse BJ, et al. Assessment of dietary
intake of lysine and arginine in patients with herpes simplex. J Am Diet Assoc
1987:87:1560–1.
4. Flodin NW. The metabolic roles, pharmacology, and toxicology of
lysine. J Am Coll Nutr 1997;16:7–21 [review].
5. Griffith RS, Norins AL, Kagan C. A multicentered study of lysine
therapy in herpes simplex infection. Dermatologica 1978;156:257–67.
6. Griffith RS, Walsh DE, Myrmel KH, et al. Success of L-lysine therapy
in frequently recurrent herpes simplex infection. Dermatologica
1987;175:183–90.
7. Milman N, Scheibel J, Jessen O. Lysine prophylaxis in recurrent herpes
simplex labialis: a double blind, controlled crossover study. Acta Derm Venereol
1980;60:85–7.
8. DiGiovanna JJ, Blank H. Failure of lysine in frequently recurrent
herpes simplex infection. Treatment and prophylaxis. Arch Dermatol
1984;120:48–51.
9. Kagan C. Lysine therapy for herpes simplex. Lancet 1974;i:137
[letter].
10. Milman N, Scheibel J, Jessen O. Failure of lysine treatment in
recurrent herpes simplex labialis. Lancet 1978;ii:942 [letter].
11. Holden M, Molloy E. Further experiments on the inactivation of herpes
virus by vitamin C (l-ascorbic acid). J Immunol 1937;33:251–7.
12. Terezhalmy GT, Bottomley WK, Pelleu GB. The use of water-soluble
bioflavonoid-ascorbic acid complex in the treatment of recurrent herpes labialis. Oral
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13. Eby GA, Halcomb WW. Use of topical zinc to prevent recurrent herpes
simplex infection: review of literature and suggested protocols. Med Hypotheses
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14. Brody I. Topical treatment of recurrent herpes simplex and
post-herpetic erythema multiforme with low concentrations of zinc sulphate solution. Br J
Dermatol 1981;104:191–4.
15. Apisariyakulm A, Buddhasukh D, Apisariyakul S, Ternai B. Zinc
monoglycerolate is effective against oral herpetic sores. Med J Aust 1990;152:54.
16. Nead DE. Effective vitamin E treatment for ulcerative herpetic
lesions. Dent Survey 1976;52(7):50–1.
17. Fink M, Fink J. Treatment of herpes simplex by alpha-tocopherol
(vitamin E). Br Dent J 1980;148:246 [letter].
18. Vynograd N, Vynograd I, Sosnowski Z. A comparative multi-centre study
of the efficacy of propolis, acyclovir and placebo in the treatment of genital herpes (HSV).
Phytomedicine 2000;7:1–6.
19. Skinner GRB, Hartley CE, Millar D, Bishop E. Possible treatment for
cold sores. Br Med J 1979;2:704.
20. Lamey PJ, Biagioni PA. Relationship between iron status and
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1995;14:604–5.
21. Wölbling RH, Leonhardt K. Local therapy of herpes simplex with
dried extract of Melissa officinalis. Phytomedicine 1994;1:25–31.
22. Koytchev R, Alken RG, Dundarov S. Balm mint extract (Lo-701) for
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23. Erdelmeier CA, Cinatl J Jr, Rabenau H, et al. Antiviral and
antiphlogistic activities of Hamamelis virginiana bark. Planta Med
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24. Baumgärtner M, Köhler S, Moll I, et al. Localized treatment
of herpes labialis using hamamelis special extract: a placebo-controlled double-blind study.
Z Allerg Med 1998;74:158–61.
25. Partridge M, Poswillo D. Topical carbenoxolone sodium in the
management of herpes simplex infection. Br J Oral Maxillfac Surg
1984;22:138–45.
26. Serkedjieva J, Manolova N, Zgorniak-Nowosielska I, et al. Antiviral
activity of the infusion (SHS-174) from flowers of Sambucus nigra L., aerial parts of
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before making any changes in prescribed medications. Information expires March 2005.
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