Period cold sores are hormone-triggered HSV-1 reactivation. Treat at the first tingle - antivirals work early, not late - and watch contagion during outbreaks.
What to do
Common questions
Why do I get cold sores on my period?
Cold sores on your period are the cold sore virus - HSV-1, which most adults carry dormant - reactivating on a hormonal cue. The virus lives quietly in nerve cells and wakes when the body's defenses shift: stress, sunburn, fever, fatigue, and hormonal swings are the classic triggers, per MedlinePlus. The premenstrual estrogen-and-progesterone drop is exactly that kind of shift, which is why some women get a cold sore on schedule, every cycle or every few. The practical game is timing: the golden window is the tingle. Antiviral cream or a prescription antiviral pill started at the first tingling can abort or shorten the outbreak; started after the blister forms, much less help. If your outbreaks are period-linked, you know your high-risk days - some women with frequent outbreaks ask their doctor about suppressive antivirals. Docosanol or plain petroleum jelly soothes; sunscreen on the lip helps if sun stacks onto the cycle trigger. Contagion care during an outbreak: no kissing, no sharing lip products or towels, wash hands after touching the sore, and never touch then touch your eyes or genitals. Outbreaks that are frequent, severe, or slow to heal - or cold sores near the eyes - deserve a doctor visit. Pymander is a free AI doctor, 24/7 by text. Describe your outbreak timing, and it can help you plan prevention.