Why do My Cold Sores Keep Coming Back?

Once infected with the HSV virus, the virus remains in your body for life.¹ Throughout your lifetime, it cycles through inactive and active periods, and can remain dormant for long periods of time. As a result, people who suffer from cold sore outbreaks typically get them at different intervals throughout their life.

Can cold sore outbreaks be predicted?

There’s no way to predict exactly when a cold sore outbreak is going to occur, although science has uncovered that certain triggers such as viral infection, sun exposure, stress or trauma to the mouth can stimulate in the activation of the virus, resulting in an outbreak.2 While avoiding these triggers is not guaranteed to keep you from getting a cold sore, doing so may help lower your risk of an outbreak.

Interestingly, while the frequency and duration of cold sore outbreaks are unpredictable, most cold sores tend to develop in the same place as in previous outbreaks. Over time, some cold sore sufferers report being able to identify the symptoms of an oncoming cold sore, allowing them to begin treating the outbreak immediately.


Additional resources:

How to Apply Sitavig

  1. Mayo Clinic (May 15, 2015). Cold Sore – Symptoms [Diseases and Conditions web post]. Retrieved August 15, 2015, from http://www.mayoclinic.org/diseases-conditions/cold-sore/basics/symptoms/con-20021310
  2. EMedicine Health (August 13, 2015). Cold Sores — Cold Sore Causes [Glossary]. Retrieved August 15, 2015, from http://www.emedicinehealth.com/cold_sores/article_em.htm#cold_sore_causes
Indication & Important Safety Information


Sitavig® (acyclovir) 50 mg buccal tablet is indicated for

the treatment of recurrent herpes labialis (cold sores) in immunocompetent



  • Sitavig® (acyclovir) 50 mg buccal tablet should not be used in patients with known hypersensitivity to acyclovir, milk protein concentrate, or any other component of the product.
  • Sitavig has not been studied in immunocompromised patients. No interaction studies have been performed. Sitavig’s safety and efficacy have not been established in pediatric patients.
  • There are no available data on Sitavig use in pregnant women. However, published observational studies over decades of use of acyclovir have not identified a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. It is not known if Sitavig is excreted in breast milk; however, systemic exposure following buccal administration of acyclovir is minimal. Before administration, discuss if the patient is lactating or planning to breastfeed.
  • The possibility of viral resistance to acyclovir should be considered in patients who fail to respond or experience recurrent viral shedding during therapy.
  • In a controlled clinical trial, the most common side effects (greater than or equal to 1%) for Sitavig were: headache (3%), dizziness (1%), lethargy (1%), gingival (gum) pain (1%), aphthous stomatitis (canker

    sores) (1%), application site pain (1%), application site irritation (1%), erythema (redness) (1%), and rash (1%). In the same trial, these side effects ranged from 0% to 3% for placebo.

You are encouraged to report negative side effects of prescription

drugs to the FDA. Call

1-800-FDA-1088 or visit www.fda.gov/medwatch.

Please see Full Prescribing Information.