Why Do Cold Sores Keep Coming Back? The Science Explained

Around 70–80% of people in the Australian community carry herpes simplex virus type 1 (HSV‑1) – the main virus behind cold sores – often without even realising it.

If you’re one of the many Australians who gets that familiar tingle on the lip before a blister appears, you’re definitely not alone. And if you feel frustrated that cold sores keep coming back just when you have a big event, a date, or an important work presentation… you’re in the right place.

In this article, we’ll unpack:

• What the herpes simplex virus actually is
• Why cold sores come back again and again instead of “going away” for good
• The most common cold sore triggers (including some very Aussie ones)
• Which cold sore treatments work – and which are mostly hype
• When it’s worth seeking an antiviral prescription or even daily prevention
• How online doctors (like our team at NextClinic) can help you stop cold sores from ruling your social life

We’ll draw on Australian sources like Healthdirect, NHMRC and Queensland Health, plus our experience as an Australian telehealth service helping people manage cold sores and herpes every day.

By the end, you’ll understand the science of why your cold sores keep coming back – and have a clear, practical plan to take back control.

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Meet the culprit: the herpes simplex virus

Cold sores are caused by the herpes simplex virus (HSV), most often type 1 (HSV‑1). Type 2 (HSV‑2) is more commonly linked with genital herpes, but both types can infect the mouth or genitals.

A few key points:

• HSV‑1 = usually oral herpes (cold sores)
• HSV‑2 = usually genital herpes
• Either type can technically show up in either place, especially through oral sex

Globally, HSV‑1 infection is incredibly common – the World Health Organization estimates around 3.8 billion people under 50 carry it. In Australia, NHMRC and Queensland Health estimates suggest around 8 in 10 adults have been infected by HSV‑1 by the time they reach adulthood.

So if you get cold sores, you’re in very crowded company.

Why you don’t “clear” HSV

Unlike a typical cold or flu, HSV doesn’t leave your body when the symptoms settle. After the first infection:

1. The virus travels along your nerves and
2. Hides out in a group of nerve cells (a “ganglion”) near your spine or skull
3. It then lies dormant (inactive) for long periods
4. Every so often, something triggers it to “wake up” and travel back along the nerve to the skin
5. That’s when you see a cold sore outbreak on or around your lips

Your immune system keeps HSV mostly under control, but it can’t eliminate it entirely. That’s why we talk about “managing” or “controlling” cold sores – not curing them.

How do you catch cold sores in the first place?

Most Australians pick up HSV‑1 in childhood through everyday contact, not through sexual activity.

Common ways the virus spreads include:

• Kissing someone with an active cold sore
• Sharing cups, bottles, cutlery or straws
• Sharing lip balms, lipsticks or toothbrushes
• Saliva contact with broken skin
• Oral sex (this is how oral HSV‑1 can cause genital herpes in a partner)

You can catch it even when there’s no obvious blister, because HSV can shed from normal‑looking skin or saliva. The risk is highest when the blister is fresh and weeping, but it doesn’t need to look dramatic to be infectious.

Once infected, many people never get obvious cold sores. Others might get one or two in a lifetime. And then there are those unlucky few who seem to get a new one every time they’re run down.

So what makes your cold sores keep coming back?

The big question: why do cold sores keep coming back?

Short answer: because HSV‑1 never left – it just went quiet.

The virus is constantly playing a tug‑of‑war with your immune system. Most of the time, your immune defences are winning. But when something weakens or distracts those defences, HSV seizes the moment and reactivates.

Those “somethings” are the cold sore triggers.

Common cold sore triggers (especially in Australia)

Different people have different triggers, but some come up again and again in the research – and in what our patients tell us.

Here are the big ones.

1. Sun exposure (big one for Aussies)

Excess UV exposure, especially on the lips, is one of the most well‑known cold sore triggers. The WHO and Australian health agencies all list sun exposure as a factor that can reactivate HSV.

Why it matters:

• UV light can damage skin cells and temporarily suppress local immune responses
• The lips have thin, delicate skin that burns easily
• Classic scenario: a big day at the beach or cricket, then a tingle on your lip 1–3 days later

If you always seem to get a cold sore after a summer weekend outdoors or a snow trip with lots of glare, sun is probably a major trigger for you.

2. Illness and fever (“I get a cold sore every time I get sick”)

The name “cold sore” isn’t an accident. Many people find they pop up:

• During or just after a cold or flu
• With COVID‑19 or other viral infections
• When they’re run down from any illness

When your body is busy fighting another infection, HSV can sneak out of hiding for a quick flare‑up. WHO explicitly lists illness or fever as reactivation triggers.

3. Emotional stress & lack of sleep

Big work deadlines, relationship stress, exams, caring for kids – mental load can show up on your lips.

Stress hormones like cortisol can:

• Suppress parts of your immune response
• Disrupt sleep
• Lead indirectly to poor diet and more alcohol or caffeine

All of that makes it easier for HSV to reactivate. Many people report that major life events (weddings, funerals, job interviews) are prime cold sore times – just when you want them least.

4. Hormonal changes (especially around periods)

Hormonal fluctuations around menstruation are a recognised herpes trigger.

Some women notice:

• A cold sore every cycle or
• Flares clustered around particularly heavy or painful periods
• More frequent outbreaks during perimenopause, when hormones are more volatile

If your cold sores seem to sync with your menstrual calendar, hormones could be playing a key role.

5. Skin injury or irritation

Anything that irritates or breaks the skin on or around your mouth can provide an opening:

• Cracked, dry lips
• Windburn or chapped lips
• Dental work (especially around the front teeth)
• Cosmetic procedures around the mouth
• Aggressive exfoliation or waxing above the lip

HSV tends to travel back down the same nerve branch, so it often reappears in the same spot. Local trauma in that area can be enough to wake it.

6. Weather extremes: cold, wind and dryness

On top of UV exposure, the Aussie climate can be brutal in other ways:

• Dry indoor air from air‑conditioning or heating
• Winter winds that chap the lips
• Sudden temperature changes

Dry, cracked lips are more vulnerable to both infection and reactivation.

7. Fatigue, poor diet and alcohol

The evidence here is more indirect, but many people notice more outbreaks when:

• They’re chronically tired
• Skipping meals or eating poorly
• Drinking more alcohol than usual

These factors can chip away at your immune function and overlap with stress and social situations (like parties and holidays) where you’re already more exposed to sun and late nights.

Myths vs reality: is it something I did wrong?

Because “herpes” carries so much stigma, a lot of people quietly blame themselves for their cold sores. Let’s be clear:

• Cold sores don’t mean you’re dirty or unhygienic
• They don’t prove you’ve had lots of sexual partners
• Most Australians caught HSV‑1 as kids, from family or friends, not through sex

Good hygiene does matter – for example:

• Washing your hands after touching a cold sore
• Avoiding sharing lip products, razors, or towels
• Not touching your eyes after touching an active sore (to reduce the risk of eye infection)

But getting cold sores is not a moral failing or a sign you’ve done something “wrong”. It’s a common viral infection that your immune system and nervous system are now hosting – like millions of other Australians.

Recognising your cold sore pattern

Understanding your own pattern is one of the most powerful tools you have.

Most outbreaks follow a rough sequence:

1. Prodrome (early warning) – burning, tingling, or itching on or near the lip
2. Blister stage – small, fluid‑filled blisters appear, often clustered
3. Ulcer stage – blisters burst and form shallow open sores
4. Crusting stage – a scab forms as the sore dries
5. Healing stage – the scab falls off and the skin heals

The whole thing usually takes 7–14 days from start to finish, though Healthdirect notes that many cold sores clear within about 2 weeks.

Some people only ever feel the prodrome; others get the full dramatic blister.

Take note of:

• How often you get cold sores (once a year, every month, only when sick?)
• What was happening in the week or two before (sun, illness, stress, periods?)
• How severe they are (tiny spot vs big cluster, painful vs mild)
• Where they appear (same spot every time or moving around?)

Keeping a simple “cold sore diary” in your phone can quickly reveal your personal cold sore triggers – and help you and your doctor build a smarter prevention plan.

Cold sore treatment: what actually works?

There’s no way (yet) to remove HSV‑1 from your body completely. So cold sore treatment has three main goals:

1. Shorten how long each outbreak lasts
2. Make each outbreak less painful and noticeable
3. Reduce how often outbreaks happen (and how contagious you are overall)

Let’s look at the main options, from simple self‑care to antiviral prescriptions.

1. Self‑care and over‑the‑counter options

These won’t “cure” cold sores, but they can make life a lot more comfortable.

At the very first tingle:

• Apply a topical antiviral cream (for example, aciclovir cream) from a pharmacy, as soon as you notice symptoms. These creams can slightly shorten healing time if started very early.
• Use a cool compress (clean cloth soaked in cold water) for a few minutes at a time to ease pain and swelling.

During the blister and crusting stages:

• Take over‑the‑counter pain relief like paracetamol or ibuprofen if needed (following the packet directions or your doctor’s advice)
• Try topical anaesthetic gels (like those containing lignocaine or benzocaine) to numb the area temporarily
• Keep the area clean and dry – gently wash with water, pat dry
• Dab on a little petroleum jelly (like Vaseline) to prevent cracking and bleeding

For the sun‑sensitive crowd:

• Use a lip balm with SPF 30+ or higher, and reapply often – especially at the beach, by the pool, or in the snow
• Wear a wide‑brimmed hat and seek shade where possible

Healthdirect emphasises that while cold sores usually heal on their own, medicines and self‑care can significantly ease symptoms and prevent complications in vulnerable people.

2. Oral antiviral prescription medicines

This is where treatment can really move from “suffer through it” to “take control of it”.

Doctors commonly use three oral antivirals for cold sores and herpes: aciclovir, valaciclovir and famciclovir.

These medicines work by blocking HSV’s ability to copy itself. They don’t remove the virus from your nerves, but they can:

• Cut down how long an outbreak lasts
• Reduce the pain and size of the sore
• Help the skin heal faster
• Reduce the amount of virus you shed during an outbreak (and therefore how infectious you are)

There are two main ways doctors use them:

a) Episodic treatment

You take antivirals only when you feel an outbreak coming on.

• You start as soon as you notice tingling or burning, or as soon as the blister appears
• Treatment usually runs for a few days (your doctor will prescribe a specific dose and duration)
• The earlier you start, the better – WHO notes treatment is most effective if begun within 48 hours of symptoms starting

This approach suits people who:

• Get cold sores occasionally
• Can recognise their early warning signs
• Want to shorten each outbreak

b) Suppressive (preventive) therapy

You take a lower dose of antivirals every day for a longer period – often months – to reduce how often cold sores appear.

WHO notes that daily suppressive therapy can significantly cut down the frequency of herpes outbreaks and is often recommended for people who get very painful or frequent recurrences.

This might be an option if:

• You’re getting cold sores very often (e.g. every month or every second month)
• Your outbreaks are severe, affecting eating, speaking, or mental health
• They’re causing major issues in your relationships or sex life
• You have a weakened immune system and even “mild” cold sores can become serious

Suppressive therapy needs a proper discussion with a doctor, because:

• It’s longer‑term medication
• It can interact with other medicines
• Your kidney function and other health conditions need to be considered

At NextClinic, our doctors frequently discuss episodic vs suppressive antiviral prescriptions with patients over telehealth, and will only prescribe if it’s clinically appropriate for your situation.

3. Planning around known triggers

For some people, doctors may suggest short bursts of antivirals around predictable triggers, such as:

• A planned holiday in the sun
• Upcoming dental work (if previous dental visits triggered sores)
• A big event you absolutely don’t want a cold sore for, like a wedding

This is sometimes called pre‑emptive treatment. Whether it’s suitable depends on your history and overall health, so it’s something to chat about with a GP or telehealth doctor rather than self‑starting.

4. Complementary options: what’s the evidence?

You’ll see lots of online chatter about:

• Lysine supplements
• Lemon balm (Melissa officinalis)
• Aloe vera
• Essential oils
• Toothpaste, vinegar, alcohol, and more

A few notes:

• Some small studies suggest lysine and lemon balm may reduce recurrence or shorten healing in some people, but the evidence is mixed and not as strong as for prescription antivirals.
• Many home remedies (like putting alcohol, peroxide or undiluted essential oils on sores) can irritate or burn the skin, sometimes making things worse

If you’re keen to try supplements or herbal creams:

• Treat them as adjuncts, not replacements, for evidence‑based treatment
• Talk to your GP or pharmacist about possible interactions with your other medicines
• Stop anything that seems to worsen irritation or delay healing

5. What doesn’t treat cold sores

• Antibiotics – cold sores are viral, so antibiotics don’t help and can cause side effects or antibiotic resistance
• Popping or picking the blister – this increases the risk of spreading the virus and secondary bacterial infection
• Tanning beds or deliberate sun exposure – some people mistakenly think “drying out” the sore in the sun will help; in reality, UV often triggers and worsens outbreaks

How to stop cold sores from coming back so often

You can’t remove HSV‑1 completely, but you can dramatically reduce how much it impacts your life.

Think in three layers:

1. Avoid or reduce triggers where possible
2. Act early when you feel a flare coming on
3. Consider preventive antiviral treatment if outbreaks are frequent or severe

1. Tackle your personal cold sore triggers

Use your cold sore diary to identify patterns, then make small but consistent changes:

• Sun‑related flares
  • Keep an SPF 30+ lip balm in your bag, car, and beach bag
  • Reapply every 2 hours when outdoors, more if swimming or sweating
  • Wear a wide‑brimmed hat and seek shade during peak UV times
• Illness‑related flares
  • Stay up to date with recommended vaccines (like flu and COVID‑19 where eligible)
  • Practice sensible hygiene (handwashing, not sharing drinking bottles)
  • Prioritise rest and fluids when you’re run down
• Stress‑related flares
  • Build in small, realistic stress‑management habits: short walks, breathing exercises, regular sleep times
  • If anxiety is a big factor, it might be worth reading posts like our guide on managing Sunday anxiety and sick days (see “Sunday Scaries or Anxiety? When to Call in Sick” on our blog), and talking to your GP about support
• Period‑related flares
  • Track outbreaks alongside your menstrual cycle
  • If there’s a clear pattern, discuss it with a doctor – sometimes timing episodic antiviral treatment around your period can help

2. Have a clear “action plan” for the first tingle

Work with your GP or an online doctor to create a plan that might look like:

• Step 1: At the first tingle, start your topical cream and/or oral antiviral (if prescribed)
• Step 2: Switch to gentle self‑care – cold compresses, pain relief, keeping the area clean
• Step 3: Follow simple rules to protect others
  • No kissing, especially babies or people with weakened immunity
  • Avoid sharing cups, cutlery, lip balms or towels
  • Avoid oral sex until the area is fully healed, to reduce the risk of giving your partner genital herpes from oral HSV‑1

Having tablets and creams on hand at home (or in your travel kit) means you can treat early instead of scrambling once the blister is well established.

If you’ve previously had a script but lost the prescription or SMS token, our blog post [“Lost Your Prescription? Here’s the Fastest Fix”](https://nextclinic.com.au/blog/lost-your-prescription-heres-the-fastest-fix) explains how to sort it quickly through your GP, pharmacy, or a telehealth prescription.

3. Consider suppressive therapy if outbreaks are really frequent

If cold sores are:

• Coming back several times a year
• Interfering with work (e.g. frontline roles, public‑facing jobs)
• Impacting your mental health, self‑esteem or sex life
• Severe because you’re immunocompromised

…then it’s worth discussing daily antiviral suppression with a doctor.

Together you can weigh up:

• How often you’re getting outbreaks now
• Your other medical conditions and medicines
• How long to stay on suppressive therapy before reassessing
• Whether you also need a cold sore treatment plan for any breakthrough flares

Daily antivirals aren’t necessary or right for everyone, but for some people they’re life‑changing.

Cold sores, sex and your partner’s health

Because HSV‑1 can cause both oral and genital herpes, it’s important to understand what your cold sores mean for your sex life.

Key points:

• Oral HSV‑1 can spread to a partner’s genitals via oral sex, especially during or just before an outbreak
• Even without visible sores, there can be asymptomatic shedding, though the risk is lower than during a full blister
• Using condoms and dental dams, and avoiding oral‑genital contact during tingling or visible sores, reduces risk (though doesn’t bring it to zero)

If you or your partner already have genital herpes (HSV‑1 or HSV‑2):

• Daily suppressive antivirals can lower recurrence and, for genital HSV‑2, reduce the risk of passing it on – something WHO and Australian STI guidelines highlight.
• Honest conversations and good information are key – stigma and secrecy tend to cause more harm than the virus itself

At NextClinic, we regularly provide sexual health consultations via telehealth for people with questions about herpes, STI testing, contraception and more. If you’d prefer not to sit in a waiting room to talk about these topics, you can start with our [telehealth consultation service](https://nextclinic.com.au/telehealth-consultation) and have a discreet phone chat with an Australian‑registered doctor.

When should you see a doctor about cold sores?

Cold sores are common and usually mild, but there are times when you shouldn’t just ride them out.

See a GP or telehealth doctor if:

• You get cold sores very often (e.g. more than 4–6 times a year)
• Outbreaks are large, very painful, or last longer than 2 weeks
• You’re not sure it is a cold sore – for example, the sore is inside the mouth, on the tongue, or looks different to past episodes
• You have sores near or in your eyes – eye herpes (herpetic keratitis) can threaten vision and needs urgent assessment
• You have a weakened immune system (e.g. from HIV, cancer treatment, immune‑suppressing medicines)
• You’re pregnant and have a first‑ever outbreak of oral or genital herpes
• A newborn baby has been in close contact with someone who has an active cold sore

Australian sources like Healthdirect and NHMRC specifically urge parents to seek medical help promptly if babies or young children are exposed to or develop cold sores, or if a child has a red, painful eye after touching a sore.

How NextClinic can help (without you leaving the couch)

As an Australian telehealth service, we designed NextClinic to make it easier to manage common conditions like cold sores without dragging yourself to a waiting room.

Through our [online doctor consultations](https://nextclinic.com.au/telehealth-consultation), our AHPRA‑registered GPs can:

• Assess whether your symptoms sound consistent with HSV‑1
• Rule out obvious red flags that need in‑person or emergency care
• Discuss your cold sore triggers and help you map out a prevention strategy
• Provide an antiviral prescription (eScript) if clinically appropriate, sent straight to your phone for use at any Australian pharmacy
• Help you decide whether episodic or suppressive treatment makes sense for you
• Issue a medical certificate for work or study if an outbreak is bad enough that you need time off, through our express or consultation pathways

If you’re dealing with stress or anxiety around sick leave, you might also find our blog posts [“Common Medical Certificate Myths Debunked”](https://nextclinic.com.au/blog/common-medical-certificate-myths-debunked) and [“GP Closed for Christmas? How to See a Doctor Online”](https://nextclinic.com.au/blog/gp-closed-for-christmas-how-to-see-a-doctor-online) reassuring – they explain how online medical certificates and telehealth fit into the Australian system.

And if you ever lose the script for your antiviral medication, our guide [“Lost Your Prescription? Here’s the Fastest Fix”](https://nextclinic.com.au/blog/lost-your-prescription-heres-the-fastest-fix) walks you through replacing it quickly, including telehealth options.

(Important note: telehealth isn’t suitable for emergencies. If you or someone else has severe symptoms such as chest pain, difficulty breathing, sudden confusion, or a seriously unwell baby, call 000 or go to the nearest emergency department.)

Living well with HSV‑1: more than just managing a blister

It’s easy to focus only on the physical part of a cold sore – the sting, the scab, the inconvenience.

But for many people, the emotional side is just as big:

• Feeling embarrassed in photos or at work
• Worrying about kissing a new partner
• Stressing about passing the virus to kids or loved ones
• Anxiety every time a tingle starts: “Here we go again…”

If that’s you, you’re far from alone. Queensland Health notes that herpes diagnoses can be stigmatising and affect relationships, and that some people benefit from psychological support as they come to terms with it.

Support can look like:

• A frank chat with a GP or telehealth doctor
• Speaking with a psychologist or counsellor
• Getting evidence‑based information from sites like
  • Healthdirect’s cold sore overview
  • Queensland Health’s herpes information
  • NHMRC’s cold sore fact sheet

Once you understand just how common HSV is, and how many tools exist to control it, it usually feels a lot less scary.

Bringing it all together – and your next step

Let’s recap the key takeaways:

• Cold sores keep coming back because HSV‑1 lives quietly in your nerve cells for life, reactivating when your immune system is under pressure
• In Australia, most adults carry HSV‑1, often from childhood – you’re not alone and you’re not “dirty” or at fault
• The big cold sore triggers include sun exposure, illness, stress, hormonal changes, skin irritation, weather extremes and fatigue
• There’s no cure, but there are effective cold sore treatments:
  • Self‑care and over‑the‑counter creams
  • Oral antiviral prescriptions taken at the first tingle
  • Daily suppressive antivirals for frequent or severe outbreaks
• You can stop cold sores from ruling your life by:
  • Identifying and reducing your personal triggers
  • Having a clear “first tingle” action plan
  • Talking to a doctor about episodic vs suppressive treatment
• Telehealth services like ours at NextClinic make it easy to get expert advice, antiviral prescriptions and medical certificates online anywhere in Australia, without the waiting room

Your challenge for this week

Pick one practical strategy from this article and actually try it over the next week:

• Start a simple cold sore trigger diary in your phone
• Buy and start using an SPF lip balm every time you’re outdoors
• Book a telehealth consultation to ask whether antivirals are right for you
• Talk openly with your partner about cold sores and how you’ll manage them together
• Read one of the linked resources (like Healthdirect or our own blog posts) and jot down questions for your GP

Then, if you’re reading this on the NextClinic blog, drop a comment and tell us:

• Which strategy you chose, and
• What you noticed after putting it into practice

Your experience might be exactly what another Aussie needs to finally feel less alone – and more in control – of their cold sores.

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