Cold Sores
Cold sores are small, fluid-filled blisters that usually appear on or around the lips. They're caused by the herpes simplex virus (HSV) and are common and highly contagious
About cold sores
Once someone is infected with HSV, the virus stays dormant in nerve cells and can reactivate periodically, triggered by things like stress, illness, sunlight, tiredness or hormonal changes. Cold sores aren't usually serious and clear up on their own within 7-10 days, though they can be uncomfortable and recur
Treatments
Symptoms
• Tingling, itching or burning before a blister appears
• Small, fluid-filled blisters, usually around the mouth
• Blisters bursting and forming a crust or scab
• Mild soreness or pain at the site
• Occasionally, a mild fever or swollen glands with a first infection
Diagnosis
Cold sores are usually diagnosed by their typical appearance and location without further tests. A swab test can confirm HSV if the diagnosis is unclear or sores appear elsewhere
Treatment
Antiviral cream (such as aciclovir) applied at the first tingling sign can shorten an outbreak if started early. Cold sore patches and simple pain relief can ease discomfort. Frequent or severe outbreaks may be treated with oral antiviral tablets
Prevention and self-care
• Apply treatment as soon as tingling starts
• Avoid touching or picking at cold sores
• Wash hands after touching a sore
• Avoid kissing or sharing cups, cutlery, towels and lip products during an outbreak
• Use a sunscreen lip balm if sunlight is a trigger
• Manage stress and get enough rest
Reviewed by Hamza Iqbal Naheed, Superintendent Pharmacist, GPhC 2209194 (check the register) · Last updated 21 September 2026