Fever blisters, also known as cold sores, are clusters of small, itchy or painful blisters and sores that usually develop on or around the mouth. The National Institute of Dental and Craniofacial Research estimates that more than 95 percent of fever blisters are caused by the herpes simplex-1 virus, while the remaining 5 percent or so are caused by the herpes simplex-2 virus, which usually causes genital herpes 1. Until the sores heal, the NIDCR recommends a soft, bland diet to avoid irritation.
If you are experiencing serious medical symptoms, seek emergency treatment immediately.
Cold foods relieve fever blister discomfort by numbing sensitive nerve endings and decreasing swelling. However, among juices, parents should select non-acidic varieties, such as:
- orange juice
- may make fever blister discomfort worse
The same options also work well for adults.
Foods to Avoid With Fever Blisters
Fish is rich in an amino acid called lysine, which may reduce the frequency and severity of fever blister outbreaks, according to holistic medicine specialist Alan R. Gaby, M.D. in his 2006 book, “Natural Pharmacy.” Lysine works by counteracting the growth-promoting effects of another amino acid, called arginine, on the herpes simplex virus and triggering the production of an enzyme called arginase that actually breaks arginine down. Although other foods -- including meats and poultry -- also contain high levels of lysine, fish is an especially good choice during an active outbreak because it is tender and easy to chew. Tough cuts of meat and poultry can scrape or scratch tender fever blisters and bones can poke. However, you should take care to choose fresh or frozen fish. The brine solutions used to preserve canned or dried fish may irritate fever blisters.
- Fish is rich in an amino acid called lysine, which may reduce the frequency and severity of fever blister outbreaks, according to holistic medicine specialist Alan R. Gaby, M.D.
- in his 2006 book, “Natural Pharmacy.” Although other foods -- including meats and poultry -- also contain high levels of lysine, fish is an especially good choice during an active outbreak because it is tender and easy to chew.
Fruits and Vegetables
All people with fever blisters benefit from eating more fruits and vegetables, writes University of Wisconsin professor David Rakel, M.D. in his 2007 book, “Integrative Medicine.” For adults, Rakel recommends at least seven or eight servings per day 5. For children, parents should base the number and size of servings on age. Fruits and vegetables contain nutrients that specifically help the immune system fight the herpes simplex virus and otherwise contribute to general health. While citrus fruits can make symptoms worse during an active outbreak, Rakel says that all other fruits and vegetables are fair game. Most fruits are already soft, but you may have to cook some types of vegetables so they don't irritate the blisters.
- All people with fever blisters benefit from eating more fruits and vegetables, writes University of Wisconsin professor David Rakel, M.D.
- in his 2007 book, “Integrative Medicine.” For children, parents should base the number and size of servings on age.
Foods to Avoid With Fever Blisters
Vitamins and Minerals for Fever Blisters
Lysine Herpes Diet
Salt and Cold Sores
Remedies for Children With Cold Sores
Swimming and Chickenpox
Foods to Heal Thrush
Foods to Eat to Avoid Shingles
What to Eat When You Have a Sore Throat
- National Institute of Dental and Craniofacial Research: Fever Blisters and Canker Sores
- American Academy of Pediatrics: Mouth Ulcers
- American Academy of Pediatrics: Oral Herpes
- “Neuroscience Research”; Caffeine Inhibits Paresthesia Induced by Herpes Simplex; Kimiyasu Shiraki, Ph.D. et al.
- “Integrative Medicine”; David Rakel, M.D.
- “Natural Pharmacy: Complete A to Z Reference to Alternative Treatments for Common Health Conditions”; Alan R. Gaby, M.D.
- Ramchandani M, Kong M, Tronstein E, et al. Herpes Simplex Virus Type 1 Shedding in Tears and Nasal and Oral Mucosa of Healthy Adults. Sex Transm Dis. 2016;43(12):756-760. doi:10.1097/OLQ.0000000000000522
- Institute for Quality and Efficiency in Health Care (IQWiG). Cold sores: Overview. 2018.
- Montgomery-cranny JA, Wallace A, Rogers HJ, Hughes SC, Hegarty AM, Zaitoun H. Management of recurrent aphthous stomatitis in children. Dent Update. 2015;42(6):564-6, 569-72. doi:10.12968/denu.2015.42.6.564
- Krissel JD, Bhatia A, and Thomas A. Cold sore susceptibility gene-1 genotypes affect the expression of herpes labialis in unrelated human subjects. Hum Genome Var. 2014; 1: 14024. doi:10.1038/hgv.2014.24
- Fatahzadeh M and Schwartz RA. Human herpes simplex virus infections: Epidemiology, pathogenesis, symptomatology, diagnosis, and management. J Am Acad Dermatol. 2007;57(5):737-63. doi:10.1016/j.jaad.2007.06.027
- Formica M, Kabbara K, Clark R, Mcalindon T. Can clinical trials requiring frequent participant contact be conducted over the Internet? Results from an online randomized controlled trial evaluating a topical ointment for herpes labialis. J Med Internet Res. 2004;6(1):e6.
- American Academy of Dermatologists. Cold sores: Overview.
- American Academy of Dermatologists. Cold sores: Signs and symptoms.
- American Academy of Dermatologists. Cold sores: Tips for managing.
Heather Gloria began writing professionally in 1990. Her work has appeared in several professional and peer-reviewed publications including "Nutrition in Clinical Practice." Gloria earned both a Bachelor of Science in food science and human nutrition from the University of Illinois. She also maintains the "registered dietitian" credential and her professional interests include therapeutic nutrition, preventive medicine and women's health.