Cause of cold sores

by | August 27, 2019

What is the cause of a cold sore and how can it be treated?
BY: Dr Grace Huang

You have probably heard of cold sores or even have had one at some point in your life. But perhaps you’re not entirely sure of what it is caused by and what else you may need to be concerned about.


What is a cold sore?

A cold sore is a small, painful, fluid-filled blister that most commonly occurs near the mouth or on the face, although it may infrequently appear elsewhere on the body. Cold sores tend to occur in clusters.  The appearance of a cold sore is sometimes preceded by an unusual tingling or itching sensation over the same area. The blisters then form and eventually burst, leaving shallow ulcers/open sores which scab over, forming a crusty lesion. They may come and go, with each flare lasting up to a few weeks.


What is the cause?

Cold sores are caused by the Herpes Simplex Virus (Type 1). There are two types of Herpes Simplex Viruses – Type 1 and Type 2. HSV-1, which is extremely common in the general population, usually causes cold sores, while HSV-2 tends to be responsible for genital sores. (EDITOR’S NOTE: It has been said that this virus is implicated in Alzheimer’s disease as well.)

HSV is transmitted through body secretions. HSV-1 can be transmitted through saliva via kissing, or sharing of utensils (oral-to-oral transmission), but oral-to-genital secretion can also occur through oral intercourse. This means that someone with cold sores can transmit HSV-1 to their partner’s genitals, resulting in genital sores. Individuals with HSV are most contagious when they have cold sores, but can still be infectious even when they have no sores or blisters.

Unfortunately, HSV infections are lifelong – meaning there is no cure for HSV and once infected a person carries the virus for life. This is the reason why cold sores can flare up from time to time. There are certain triggers that can set off an outbreak of cold sores – for instance, environmental factors such as sunlight and cold temperatures, or anything which weakens your immune system, such as an illness, or medications which suppress your immunity.


What are the treatments for cold sores?

While there is no cure for HSV, the good news is that anti-viral medications are extremely effective in suppressing the virus and can be used to treat an outbreak of cold sores, and even prevent or minimise future outbreaks.

Some people may not be significantly bothered by their cold sores, which flare up only occasionally and go away by themselves. However, if you are troubled by your symptoms and worried about transmission of the virus to people around you during a flare, anti-virals such as acyclovir or valacyclovir are available as both oral tablets and topical creams. Sometimes, just the topical cream may be enough to address your cold sores but if they fail to respond or if your flare is particularly bad, your doctor may prescribe a short course of tablets on top of the cream.

If you are someone who experiences frequent and painful outbreaks of cold sores, or if you are concerned about transmitting the virus to your loved ones, then suppressive anti-viral therapy may be a good option for you. This is when you take the anti-viral medication on a daily basis in order to achieve continued suppression of the virus. This not only stops flares from occurring, but also reduces your infectivity and the risk of transmitting HSV to others.

Now that you know a little more about cold sores, hopefully this has helped you realise that you do not need to live with intermittent painful outbreaks. There are treatment options available, so if this is an issue which has been troubling you, then it’s time to make that a thing of the past.


** Dr Grace Huang is a doctor at the DTAP Clinic (Dr Tan & Partners). 

(** PHOTO CREDIT: Unsplash)




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