Cold Sore & Fever Blister Treatments

Frequently Asked Questions (FAQs)


Health: How can I make a cold sore on my lip heal faster?

Ahhh! Cold sores! I get them about three times a year, and it never gets easier. I've tried a lot of different things, but most of them did not work for me. Abreva seemed to just make it spread more. Icing helps at the very onset of cold sore, but you have to hold it there for a long time. Plus, the water that drips can make it easier for the cold sore to spread. Hydrogen Peroxide did not help, and the dripping can also facilitate the spread.

Two things worked for me.

1) Medicine - Acyclovir

I take it in the form of pills. You may need a prescription for this.

2) Popping the sacs

This is extremely risky if you are not careful. In order to do this correctly, you need a sharp sterile needle, good lighting, some tissue paper (I use toilet paper), and dexterity. I wait until my cold sore has reached that stage where sacs start to form. This is right before the crusting stage, and it is the most painful, burning, itchy, and irritating stage. It usually occurs on Day 2 for me. I take a sterilized needle (burned with a lighter), and very carefully poke the sac. As the yellow mucus oozes out, I capture it with a small tissue. Not wipe! Do not wipe! Just gently dab that area gently, enough to prevent the mucus from spreading. I repeat for all the sacs. This shrunk my cold sore so much, I was able to decrease the healing time from 1 month to only 5 days. Yeah! But again, it's very risky, because it can also very easily make the cold sore worse if the mucus is not cleaned correctly.

3) Rest, water, and de-stress

Though this is not a treatment, it is pretty important. The cold sore virus just loves to suck the energy and water out of you. It can be stressful when you're self-conscious and you want/need to look good, and also feel good. Be sure to get plenty of rest and drink plenty of water, so your immune system can fight that beast at full force.


Is there a way of getting rid of cold sores for good?

At present there is no way of getting rid of cold sores permanently. Cold sores are caused by an infection and later reactivation of the Herpes simplex virus (HSV).

HSV vaccines are being worked on, but there aren't any available at present.

Interestingly, researchers have recently discovered a molecule that is the key to reactivation of HSV (see below).

The initial cold sore infection with HSV happens when HSV enters the skin through a small break in the skin near or inside the mouth. This commonly happens during childhood and can result in a fairly severe outbreak of sores and ulcerations around the lips and inside the mouth (herpetic gingivostomatitis).

After the initial infection, HSV retreats into a nerve cell body and stays there in a latent state, kept in check by the immune system until it is reactivated by a number of different stimuli, most commonly by something that lowers the function of the immune system, including: an illness such as a cold or flu

trauma to the lip or mouth area

sun exposure


menstrual cycles

HSV outbreaks are controlled, but not cured by antiviral oral medications, such as acyclovir, valacyclovir and famcyclovir. They can also be treated with topical medications such as Zovirax or Denavir creams if they are started with the first symptoms of tingling or pain and used 4-5 times a day. Starting topical medications later is not as effective.

If outbreaks are frequent, once a month or more, then prophylactic antivirals may be prescribed.

HSV is contagious until all the vesicles are completely dried up.

Interestingly, researchers have recently discovered a key molecule, VP16, production of which is necessary in order for HSV to exit its latent state in the nerve cell and come out onto the skin surface to replicate. Fever is one of the stimuli that can induce production of VP16. This molecule is a target for the development of some vaccines and treatments for HSV, so we may potentially have a cure for HSV in the future.


What causes cold sores and how do you get rid of them?

So, Cold Sores are a form of the Herpes Simplex Virus I (HSV-1). So, at the base of the problem, the cause of the sores on or around your mouth is a virus that lives in your nervous system. Once you get it, you'll have it for life - there is no cure. That said, people can have HSV-1 and not exhibit symptoms at all until some kind of trigger occurs. Common triggers include: stress, exposure to UV rays, sudden change of temperature between seasons, and in some cases, the lesions/blisters that form may also indicate some kind of disturbance in the bowel system. As far as I know, Valacyclovir (generic for the drug Valtrex, available in 500mg and 1000mg pills) is the only effective method of preventing the cold sore/lesion/blister from forming and in cases where the blister is already forming, helps to lessen the severity and duration of the blister.

HSV-1, as far as I've read, can be transferred by direct contact with the lesion or with bodily fluids during an outbreak. I have also read somewhere that the Chicken Pox virus is a close cousin to the HSV-1 virus and there may be a correlation with having had the Chicken Pox and now exhibiting symptoms associated with HSV-1.

Having used OTC treatments such as Abreva, the only truly effective method I've ever used is the Valtrex/Valacyclovir drug. Also, Duane Reade often carries a "Duane Reade" brand of Cold Sore medication. It's a liquid that's stored inside a glass vial with a gauze applicator tip. You're supposed to break the inner vial and let the applicator tip saturate with the liquid and then rub in/massage the applicator over the affected area. I think there's a liquid form of the drug which helps lessen the severity and duration of the visible sore.

EDIT 2017-Feb-17: Also, in my own personal experience and observation, sometimes you will notice little indentations or abnormalities in the surface of your fingernails. When these are visible, I often will experience a cold sore unless I take preventative action (taking the drug). I have also found that by taking a multi-vitamin (with high concentrations of Vitamin D) helps to mitigate the frequency of an outbreak.....

DISCLAIMER: I am not a doctor, med student or any medical professional. I'm only sharing information I have compiled on my own through my own research for personal use. I urge anyone reading this to confirm my findings and/or conduct their own research and come to their own conclusions. I will not be held liable in any way from the information I supplied.


Can you get a cold sore inside your nostril?

Yes. They are really painful. For me, taking extra lysine supplements like 2000-3000mg daily helps my cold sores go away fast and then Carmex or even neosporin for topical treatment.


What's the best treatment for cold sores?

Herpes viruses establish lifelong infections, and the virus cannot yet be eradicated from the body. Treatment usually involves general-purpose antiviral drugs that interfere with viral replication, reduce the physical severity of outbreak-associated lesions, and lower the chance of transmission to others. Studies of vulnerable patient populations have indicated that daily use of antivirals such as zovirax, there also some natural alternatives like L-Lysine among others...

you should talk to your doctor, he is going to know what to do right away, and if you’re showing symptoms (but haven’t been diagnosed) this is a must.


If you've got cold sores, when's the soonest you can kiss someone?

I disagree with Robert Wesley's answer that "There is no reason to worry about when to kiss someone when you sometimes get cold sores," and I would also like to correct some of the points he makes; however, most of the big picture he gives is right. (And, by the way, I don't have an answer to the specific question asked here.) Cold sores are caused by a reactivation of latent herpes simplex virus (HSV). (Robert spoke of "lytogeny" -- I think he meant to say "lysogeny", but that is a term used mainly for bacterial viruses, not those of mammals.) HSV infects most people very young, without symptoms, and rapidly establishes a latent infection in neurons in nearby ganglia. Every so often, for reasons that aren't well understood but that may be linked to UV light, stress, and/or mild immunosuppression, the virus reactivates, tracks down the neuron once again to the area of the skin that the neuron supplies, and establishes a new non-latent infection.

This new infection is a cold sore when the latent infection is in the trigeminal ganglai; it's a genital sore when the latent infection is in the sacral ganglia. There are two kinds of HSV (wittily called "type I" and "type II"); HSV I is usually associated with cold sores, HSV II with genital sores, but it's not an absolute thing.

OK, so that's the background. Some more useful numbers are the frequency of infection. It's hard to measure accurately, especially because I don't particularly trust the serological values, but there's a general consensus that somewhere between 30-80% of a population is likely to be infected with HSV (with the lower values applying to HSV II). There seems to be significant variation between populations, influenced by geography, social, economic status, etc etc. Most of these infections are asymptomatic (but could still reactivate).

Note that even at the higher end of the range there is still a significant minority of people who are uninfected, and in some populations a majority of people may be uninfected. Also note that, as I mentioned, some cases of cold sores are HSV type II and one would expect that the majority of the population would be uninfected.

There is a significant amount of virus shedding with no symptoms. This has been hard to measure but there is relatively recent data for genital herpes suggesting that at least some virus may shed every day, in little bursts, with no symptoms. I don't think anyone knows what the chance of infection is from this shedding, vs. that with outright sores; I think it's reasonable to guess that the sores have far more virus and a far higher chance of infection, but this virus is extremely successful and hard to make simple predictions about.

Cold sores are unpleasant, but usually not terribly severe. There are some severe diseases associated with HSV, though. For example, eye infections are not unusual and can lead to blindness. Even more seriously, infants infected with HSV (especially II, such as during birth if the mother has an active infection) can develop fatal encephalitis.


- you may not already be infected with HSV

- the consequences of new HSV infection may be unpleasant

- the chances of infection from an active sore are probably higher than when none is present

Given that, I think, in a non-medical-advice sort of way, that avoiding kissing when there's an open sore is a good idea. But when, exactly, it's safe to kiss, I don't have an answer.


Which is more effective for the treatment of cold sores, Zovirax or Abreva?

Which one works for you?

Both seem rather pricey for the amount you get; Abreva is a lotion/gel while Zovirax is usually a pill. Abreva is OTC; Zovirax is a prescription drug, although you can sometimes find the generic Acyclovir OTC.

Do you want to purchase and take a pill every day which may (or may not) work to lessen outbreaks, or do you want to treat an outbreak as soon as it happens, shortening or even short-circuiting the outbreak?

Me, I'd probably go with Abreva, but then, I'm cheap- and I hate taking medications.


What's the best way to fight a cold sore?

I find L-lysine the most useful thing in my patients with this particular issue. For a new cold sore, I usually use 500 mg three times a day as long as you aren't on any meds that could interact with it. In general, if you're cold-sore prone, adding a high-quality daily B-complex supplement to your regimen can boost your immune system and liver function to help prevent future outbreaks.

Of course, a healthy diet (high-plant, multi-colored, varied, low-preservative, minimally processed diet with adequate protein and good fats) and plenty of high-quality sleep are also really helpful in boosting your immune system to prevent future occurrences as well.


Why is cold sore cream so expensive?

You can get generic aciclovir cream for £2.29 on Amazon UK. That strikes me as pretty cheap.

Aciclovir is the active ingredient in the leading brand version, Zovirax, but is now out of patent. If you pay for Zovirax, you're paying for branding. If you live in a country where pharmaceuticals are poorly regulated, that might make sense, because buying a brand (if you're confident it's not counterfeit) is a way of being sure of what you're getting. Here in the UK where all pharmaceuticals are well-regulated, you'd be a fool to buy the branded rather than the cheaper generic version.


What is the difference between a cold sore and a canker sore?

A cold sore or fever blister is caused by the herpes simplex virus. You usually find them on the lips in most cases. Between 30 to 90% of the population has this virus in their body by their 30s. It is usually painless.

A cold sore is also infectious, and can spread the virus from one person to another. Triggers for cold sores include stress, UV light, and certain foods. For people who get many cold sores, taking an antiviral drug very early on can help it heal quickly.

Canker sores (aphthous ulces) are thought to be an atypical immune reaction, also caused by stress or certain foods. They can be small (minor) or big (major) and are fairly painful. Usually, the best thing to do is to avoid touching them and wait for them to go away. They will usually go away in less than two weeks by themselves.


How do you get rid of cold sores?

Cold sores suck... Accordingly, I have tried many different remedies. A few were helpful but most were worthless. I'll list out the ones that I remember trying.

1) Aciclovir cream: as mentioned by Andrew, this one works. The caveat is that you must apply the cream very early in the life cycle of a breakout. I've thwarted several outbreaks before they were even visible, but if I apply too late there are no discernible benefits. You'll also need to see a doctor for this one.

2) Campho-phenique: This is my go-to for non-prescription treatment. It has phenol which is a powerful drying agent. The camphor and menthol also works very well for pain relief. Wonderful stuff that works.

3) Lysine: More or less useless, in my honest opinion. The basic premise is that lysine can slow the absorption of amino acids that the virus needs to propagate. Your body likely has plenty of amino acids unless you are malnourished; just eat healthy and save your money.

4) Hydrogen peroxide: Cheap and effective for so many things! Peroxide will help keep the sore clean and kill off some of the virus. A few splashes throughout the day will do you well.

5) Ibuprofen Liquid: This is one I 'invented' myself. I've applied liquid ibuprofen directly onto a bad breakout in the past. Not only does it reduce pain, it also reduces swelling and redness. This is more of a palliative approach rather than actually getting rid of the sores, but it will give you some relief.

6) Releev: I have only tried this OTC medication a few times with different results. The active ingredient is benzalkonium chloride, which is a surfactant and anti-microbial. I'm not sure what the mechanism of action is supposed to be, but I was quite impressed the first time I used this one. It shortened the breakout significantly but only worked the first time. Subsequent uses for other breakouts didn't really help. I'm indifferent with this one; everyone 's body chemistry is different so if spending ~20$ isn't an issue, it may be worth a shot.

My recommendation would be to get a prescription of aciclovir, or similar pharmaceuticals, and to keep campho-phenique around. Take them with you everywhere, as it really is vital to apply as soon as possible. Lastly, an ounce of prevention is worth a pound of cure! Keep your stress levels in check since that's one of the most common triggers.