Cold sores, also known as fever blisters, are caused by infection with one of two types of the herpes simplex virus, usually type one. In the July-August 2008 issue of "Pediatric Nursing," Yale nurse practitioners Janet M. Drugge and Patricia Jackson-Allen report that 40 percent of children are infected by the age of 15. Most experience no symptoms at all, according to Drugge and Jackson-Allen, while others suffer recurrent bouts of cold sores. Lysine has attracted attention as a potential remedy for cold sores, but no studies have been performed on children.
Definition
Lysine is an essential amino acid found in proteins from fish, poultry, chicken, dairy products and legumes. The term "essential" means that humans must consume it from food because the body cannot synthesize lysine on its own. Lysine is particularly important for children because it supports growth. Symptoms of lysine deficiency---uncommon, except in vegetarians, athletes and burn patients---include lethargy, nausea, dizziness, poor appetite, agitation, bloodshot eyes, poor growth, anemia and reproductive problems.
Function
In test tubes, lysine counteracts the growth-promoting effects of another amino acid, arginine, on the herpes simplex virus. Lysine and arginine also use the same transporters to gain access to the inside of the body, so consuming more lysine limits the amount of arginine that reaches the virus in the first place. At least theoretically, consuming more lysine should reduce the frequency and severity of cold sore outbreaks in both adults and children.
Dose
Experts disagree on the amount of lysine that treats cold sores in adults; they do not even comment on doses for children. In his 2007 book, "Integrative Medicine," University of Wisconsin professor David Rakel, M.D. recommends 1 g per day to prevent cold sores and 3 g per day to treat them. In the December 2005 issue of "Alternative Medicine Reviews," holistic medicine specialist Alan R. Gaby recommends 500 mg to 3 g per day to prevent and up to 6 g per day to treat them. The University of Maryland Medical Center recommends limiting lysine doses in children 12 and younger to 10 mg per pound of body weight, but this is a general recommendation not specific to cold sores.
Safety
Gaby says lysine doses up to 6 g per day are safe for adults, at least in the short term. However, this does not mean they are safe for children. Parents or guardians should always consult their child's doctor before starting the child on any dietary supplement, including lysine. Because lysine occurs naturally in foods, adding additional servings of lysine-rich foods--such meat, poultry, fish, dairy products and legumes---may be a safe alternative to lysine supplements.
Effectiveness
Clinical studies on lysine and cold sores have only been performed on adults taking lysine in the form of supplements. These show "mixed results," according to Rakel, with some suggesting a modest, favorable effect on the frequency, severity and duration of cold sores and others suggesting no effect at all. How these results might apply to children taking lysine in the form of supplements or consuming lysine in the form of food remains uncertain.
Considerations
The American Academy of Pediatrics recommends encouraging rest and offering soft, bland diet with plenty of cool fluids until symptoms subside. Acetaminophen can be used to treat fever or excessive discomfort. Although cold sores usually resolve without treatment, children with severe, frequent or prolonged (lasting longer than two weeks) symptoms should be seen by a doctor.
References
- "Pediatric Nursing"; A Nurse Practitioner's Guide to the Management of Herpes Simplex 1 in Children; J.M. Drugge and P.J. Allen; 2008
- "Alternative Medicine Reviews"; Natural Remedies for Herpes Simplex; Alan R. Gaby, M.D. ; December 2005
- "Integrative Medicine"; David Rakel, M.D.; 2007
- University of Maryland Medical Center: Lysine
- HealthyChildren.org: Oral Herpes
