Cold sores, or fever blisters, are small fluid-filled lesions caused by the herpes simplex virus type 1 (HSV-1). Around 67% of people under 50 carry HSV-1, often without symptoms. When active, it causes recurring sores, usually on or around the lips.

The virus spreads through oral contact and remains dormant in nerve cells, reactivating due to triggers like stress, illness, sun exposure, or hormonal changes. Outbreaks begin with tingling or itching, followed by blisters that heal in 7–10 days.

There’s no cure, but antiviral medications (e.g., acyclovir, valacyclovir) and over-the-counter treatments (e.g., docosanol) can reduce symptoms and speed healing. Natural remedies like aloe vera and cold compresses may help too.

To prevent outbreaks, manage stress, protect lips with SPF, and avoid sharing items or oral contact during flare-ups. HSV-1 is contagious even without visible sores.

Frequent or severe cases should be evaluated by a healthcare provider. With the right care, cold sores can be effectively managed.