Do herpes recur more often in the winter?

Dear Cold sores?,

Despite herpes being so common among adults in the United States, it’s still a relatively misunderstood and stigmatized health issue, so kudos to you for seeking out this health information. The precise triggers of herpes simplex virus (HSV) outbreaks—also known as cold sores, fever blisters, oral herpes, or genital herpes depending on the location of the infection—remain unclear, and outbreaks are often unpredictable and vary between people. Despite the nickname of cold sores, there is minimal evidence that cold weather or temperature changes can trigger a herpes outbreak. Not everybody with an HSV infection has the same triggers, but the following factors are common ones:

• Emotional or physical stress
• Illness or a weakened immune system
• Menstruation
• Exposure to sunlight
• Friction in the area of the infection

It might help to get an understanding of how herpes works in the body and how it’s different from other common infections. Usually, when your body is exposed to a bacterial or viral invader, the immune system activates and eventually fights off the infection. However, herpes viruses are different in that they stick around permanently by hiding out in the nervous system, where they may stay dormant (or “latent”) for months, years, or even decades before reactivating and causing a new outbreak. The exact cause of reactivation is unknown, but it’s often associated with a trigger like the ones previously listed. This is why people with oral or genital herpes may experience sporadic outbreaks over time, and why people who had chickenpox as kids may develop shingles as older adults.

Finally, people may have different triggers for herpes episodes. While cold weather isn’t listed as a known or suspected herpes trigger in the research, you seem to have noticed a pattern for yourself. Perhaps winter is stressful to you (for example, due to fewer daylight hours, increased travel and holiday stressors, or exams if you’re in school), or your immune system is slightly weaker due to other seasonal illnesses. Outbreak frequency is also very variable; some people only get one or two outbreaks in their entire lives, while others might experience them four to five times a year. Typically, outbreak frequency and severity also decrease over time. You may have some success in reducing outbreak frequency by managing your triggers, but sometimes having a herpes episode is just out of your control. While there’s no cure for this virus, you might consider talking to a health care provider about herpes antiviral medication, which may speed up the healing process and reduce the frequency and intensity of episodes. Here’s to hoping that your winter HSV woes become a thing of the past.