Cold sores always seem to crop up at the most inopportune times, like your cousin’s wedding or the day you need to give a big speech — and there’s probably a reason: stress. Along with sunlight and even certain foods, stress can bring on an outbreak of cold sores, aka fever blisters.

If you’ve ever had a cold sore, caused by the herpes simplex 1 (HSV-1) virus, you’re vulnerable to repeat outbreaks, since the virus can lurk in nerve cells until something activates it again.

Related: 10 Health Symptoms Women Should Never Ignore

The sores usually appear on the lips, nose or mouth (or inside your nose or mouth), although they can show up anywhere on your body. You may notice a tingling, then bump, then a blister that oozes and eventually forms a crust. It can takes weeks for a cold sore to fully heal. Your first outbreak may bring with it a fever, body aches, a sore throat and headaches.

Here’s how to keep these unsightly, painful, highly contagious sores at bay.

Avoid cold sore triggers. Common triggers can include sunlight, wind, stress, fatigue and a cold or fever, according to the Mayo Clinic. You may also be more susceptible to cold sores during hormonal changes (such as those brought on by pregnancy or a menstrual period) or if you have had cuts or some other trauma to the mouth area, such as cosmetic surgery or dental work.

Figure out what your triggers are and avoid them if possible. Use sunscreen on your lips, advises the University of Maryland Medical Center (and don’t forget to wear a wide-brimmed hat when you’re out in the sun).

Take good care of yourself. Experts recommend getting enough sleep, eating a healthy diet and finding ways to manage stress. These lifestyle approaches help the body fend off infections.

Related: 6 Mistakes People Make When Taking Medication

Try antiviral medications. If your outbreaks are frequent, talk to your doctor about prescription antiviral medications. These include acyclovir, valacyclovir and famciclovir. To prevent an outbreak, take your medication at the first sign of tingling if you’re not already taking it daily as preventive therapy (another option), unless otherwise instructed by your doctor.

Aside from helping to prevent outbreaks, taking an antiviral medication within 72 hours of the start of an outbreak may shorten the episode, according to the Academy of Dermatology (AAD).

“Antiviral medications are the most effective, low toxicity and widely used treatments,” says Anna Korovina, PhD, a researcher at the Russian Academy of Sciences who has studied the herpes virus extensively. “The advantage of valacyclovir is that it is absorbed more rapidly and efficiently than acyclovir, so it doesn't have to be taken as often.”

Watch whom you kiss and what you touch. The HSV-1 virus is spread through an open blister or through saliva. It’s highly contagious, so if you have an outbreak, experts advise not kissing or even sharing cups or lip balm with other people. To prevent an outbreak, taking these same precautions if someone in your household has a cold sore.

Related: Is It Mono or Something Else?

Also take precautions during sex if you or your partner has an outbreak. The virus can be spread to the genitals during oral sex. HSV-1 is very similar to HSV-2, the virus that usually causes the sexually transmitted genital herpes.

If you have a young child with a cold sore, encourage him not to suck his thumb. According to the Mayo Clinic, thumb sucking can infect the fingers, causing a highly painful condition called herpes whitlow.

Also, be sure not to touch your eyes if you have a cold sore. According to the Mayo Clinic, repeated infections can cause scarring and even cause blindness.

Natural approaches to prevention

If your cold sore outbreaks aren’t that frequent or severe, you may want to try a natural approach to keeping them at bay.

Get more lysine. Some small studies suggest that taking 500 to 1,248 milligrams of the amino acid lysine a day, combined with a high-lysine diet, can reduce cold sore outbreaks, according to an article in Alternative Medicine Review. Foods high in lysine include fish, chicken, eggs and potatoes.

Talk to your doctor before taking lysine. According to the University of Maryland Medical Center, it may raise your cholesterol and triglyceride levels and boost the amount of calcium your body absorbs.

Get less arginine. If lysine cuts the risk of cold sores, another amino acid, arginine, may raise it. Foods and drinks containing arginine include beer, grain cereals, chocolate and nuts.

Cut down on sugar. The author of the article in Alternative Medicine Review, Alan Gaby, MD, notes that some patients report getting the sores after eating too many sweets.

Related: Are You Eating More Sugar Than You Think?

Try propolis. An ointment of 3 percent propolis, a resin-like material from beehives, may shorten a breakout, according to Mayo Clinic. People with asthma and or allergies to bee products shouldn’t use propolis, warns the University of Maryland. You may also want to try a cream containing sage and rhubarb, which the Mayo Clinic reports may be as effective as acyclovir cream.

Although cold sores rarely cause serious complications, they can be harmful for people with very weak immune systems and people with eczema. If you have eczema and have cold sores that appear to be spreading, see your doctor right away: The infection can be life threatening.

Mary Purcell is a freelance writer and health researcher in Piedmont, Calif., with expertise in policy analysis. She has a master's degree in Latin American studies from Georgetown University.