Cold Sores: Why Starting Treatment Early Helps, and How to Prevent Them

Cold sores (fever blisters) are small, painful blisters on or around the lips caused by the herpes simplex virus. They usually heal on their own in 7 to 10 days. Prescription antiviral medicine works best when it's started at the very first tingle or burning, before the blister appears, and can shorten the outbreak. Once you have the virus it stays in your body, and outbreaks are often set off by sun, stress, illness or a cold.

How a cold sore develops

• Tingle: itching, burning or tingling at the edge of the lip for a day or so
• Blister: a small cluster of fluid-filled blisters
• Weeping: the blisters break and ooze
• Crusting: a scab forms and the sore heals, usually without a scar

Common triggers

• Sun exposure, which is stronger at Denver's altitude
• Stress or lack of sleep
• A cold, flu or fever
• Dry, chapped lips, especially in winter
• Hormone changes, such as during a period
• Injury to the lip, including dental work

Treating a cold sore

• Prescription antivirals taken by mouth can shorten an outbreak, especially when started at the first tingle. People who get frequent outbreaks may be given a prescription to keep on hand.
• Over-the-counter creams can ease symptoms and may shorten healing slightly
• A cold compress and pain relievers can help with discomfort
• Keep the area clean, and don't pick at the scab

Avoiding spreading it

Cold sores are most contagious from the first tingle until the scab has fully healed. During that time, avoid kissing and oral contact, don't share cups, utensils, lip balm or razors, wash your hands after touching the sore, and keep it away from your eyes. Be especially careful around newborns and anyone with a weakened immune system.

Preventing outbreaks

• Use a lip balm with SPF 30 or higher, every day, and especially when skiing or hiking
• Keep lips moisturized in dry weather
• Get enough sleep and manage stress where you can
• If you get outbreaks often, ask a clinician about daily antiviral medicine

When to get seen

Come in, or start with a telehealth visit, at the first tingle if you want antiviral medicine, if a sore hasn't healed in two weeks, if you get outbreaks often, or if you have a weakened immune system. At an AfterOurs clinic, a standard self-pay visit is $175, and a self-pay in-clinic visit never costs more than $330. Telehealth is $75. We contract with all major commercial and government plans, including Colorado Medicaid and Medicare. See the cost and insurance page.

Go to the ER or get seen the same day if a sore spreads near or into the eye, or your eye becomes red, painful or sensitive to light; if a newborn has blisters or a cold sore; or if sores are widespread with a high fever, or come with confusion or a stiff neck.

Where to find us

Four clinics across metro Denver, all ages welcome, se habla español:

• Hampden (Southeast Denver): 8 AM–11 PM daily
• Littleton: 8 AM–11 PM daily
• Thornton: 8 AM–11 PM daily
• Highlands: Mon–Fri 5–11 PM, Sat–Sun 8 AM–11 PM

Walk in, or book online.