What is cold sores?
Cold sores (also called fever blisters or oral herpes) are caused by herpes simplex virus type 1 (HSV-1) — though HSV-2 can sometimes cause them too. About two-thirds of people under 50 carry HSV-1.
After initial infection, the virus lives dormant in nerve cells and reactivates periodically, causing the classic cluster of small blisters on or near the lips. Common triggers: stress, illness, sun exposure, fatigue, menstruation.
Antiviral treatment started at the first tingle can shorten the outbreak by 1–2 days. With recurrent or severe outbreaks, daily suppressive therapy can dramatically reduce frequency.
Do I have cold sores? Common signs
If most of these describe what you're experiencing, telehealth may be a good next step:
What causes it
Herpes simplex virus type 1 (HSV-1), typically acquired in childhood through saliva contact. After initial infection, the virus stays dormant in trigeminal nerve cells. Triggers for reactivation include UV light, fever, stress, fatigue, hormonal changes, and other illnesses.
Is it contagious?
Yes. HSV-1 is transmitted through direct contact with active sores or saliva. Most contagious when blisters are open and oozing, but viral shedding can occur even without visible symptoms. Avoid kissing, sharing utensils/lip balms, and oral sex during outbreaks.
The tingle is your window — antivirals work much better if you start at the first sign than after blisters appear.
Can it be treated online?
Recurrent cold sores are well-suited to telehealth. A clinician can prescribe antivirals to start at the first prodrome, or daily suppressive therapy for frequent outbreaks. First-ever outbreaks should be evaluated in person, especially if severe.
How cold sores is treated
Valacyclovir (Valtrex) is most common — a 2-gram dose twice in one day (single-day treatment) or 500mg twice daily for 3–5 days. Acyclovir and famciclovir are alternatives. For frequent recurrences (6+ per year), daily valacyclovir 500mg can reduce outbreaks by ~75%. Topical antivirals are less effective than oral. Docosanol (Abreva) is OTC and modestly helpful.
Self-care while you wait
- Start antivirals at the very first tingle, before blisters appear
- Use SPF lip balm daily — UV is a major trigger
- Don’t pick or pop the blisters
- Don’t share lip balms, drinks, or utensils during outbreaks
- Cool compress can ease pain
- OTC topical docosanol can speed healing modestly
- Manage stress and get enough sleep
How long does it last?
Untreated outbreaks last 7–10 days. Antivirals shorten this to 5–7 days, more if started during prodrome. Many people have outbreaks 1–4 times per year, decreasing in frequency over time.
Frequently asked questions
How is HSV-1 different from HSV-2?
Traditionally HSV-1 causes oral herpes and HSV-2 genital — but with more oral sex, the lines blur. Both viruses can cause sores in either location. HSV-1 in genitals causes fewer recurrences than HSV-2.
Can I give my partner genital herpes from a cold sore?
Yes — oral sex during an outbreak (or even during asymptomatic shedding) can transmit HSV-1 to the genitals. Avoid oral sex during outbreaks.
Are cold sores curable?
No — the virus stays in your nerve cells for life. But outbreaks are controllable and become less frequent over time. Daily suppressive therapy can effectively prevent them.
Will I always have outbreaks?
Frequency typically decreases with age. Some people have one and never another. Identifying and managing your triggers (UV, stress) plus antivirals at first signs keeps most outbreaks brief.
Can stress alone cause an outbreak?
Yes — stress is one of the most common triggers, likely through cortisol effects on immune surveillance.
