Cold sores are small clusters of blisters on or around the lip, caused by the herpes simplex virus. The virus stays in the body for life, but episodes get shorter when treatment starts early, and for most people they become less frequent over the years. Impetigo is a common bacterial skin infection that sits in the top layer of the skin. It shows up as sores that break open and dry into a golden-yellow crust. It is very contagious, mostly affects children, and clears quickly once it is treated.
The same eight facts on every condition comparison.
They are caused by herpes simplex.
The virus stays latent for life after the first exposure.
They recur in the same place.
Reactivation produces small blisters near the lip border.
A first infection can differ.
It may cause painful mouth and gum inflammation with fever.
Unusual sores need review.
A persistent ulcer should be reassessed, not treated repeatedly.
It is a bacterial skin infection.
Staphylococcus aureus and group A streptococci are the usual causes.
It has two forms.
Nonbullous impetigo forms crusts; bullous impetigo forms blisters.
Bacteria enter broken skin.
Eczema, scratches and bites are common entry points.
Testing is selective.
Swabs help with recurrent, resistant or unusual cases.
Blister cluster Small blisters on the lip edge.
Crusting Yellow crust as it heals.
Near the nose Can appear around the nostrils.
Non-bullous impetigo Sores with honey-colored crusts; most common.
Bullous impetigo Larger fluid-filled blisters.
Ecthyma Deeper, punched-out ulcers.
Herpes simplex virus remains in sensory nerves after the initial infection. Reactivation brings the virus back to nearby skin, where local viral activity can produce grouped blisters.
Bacteria infect the superficial skin, often after a small break in the barrier. Shallow sores or blisters can release fluid that dries into a honey-colored crust.
Cold Sores. The first infection often occurs early in life; recurrent episodes can occur at any age afterward.
Impetigo. Most common in young children, although any age can be affected.
Cold sores are caused by the herpes simplex virus. After the first infection, the virus stays in nerves and can reactivate.
Impetigo is a skin infection caused by staph or strep bacteria entering through small breaks in the skin.
Evidence labels come from each condition’s own treatment list.
The only over-the-counter cream shown to shorten an episode, and only by about half a day. It has to go on at the first tingle and be reapplied five times a day. It is a reasonable thing to keep in a bag, but antiviral tablets started at the same moment do considerably more.
Strong sun on the lips is one of the most reliable triggers there is, so for anyone whose episodes follow skiing, a beach holiday or long days outdoors, a daily SPF lip balm is genuine prevention rather than lip care. Use it every day rather than only when an episode is due, and keep using it while the mark left behind fades, since sun makes that darker and slower.
A thin gel patch worn over the sore. It keeps the area moist so the crust splits less, it stops fingers reaching the sore, and it contains the fluid that spreads the virus. It does not shorten the episode itself, and it is easier to use once the blisters have opened than at the tingle stage.
A popular supplement for preventing episodes, but the studies behind it are small, old and inconsistent. It is not dangerous and some people are convinced by it. It is not a substitute for an antiviral, and it is not something to rely on if your episodes are frequent.
Plain ointment dabbed over the crust keeps it soft so it does not split each time you talk or eat, which hurts less and leaves less of a mark. Drying the sore out does the opposite of what people expect. Apply it with a clean fingertip or a cotton bud and wash your hands afterwards - it does nothing to the virus itself.
General antiseptic ointments from the shelf are not the same thing as a prescription antibiotic ointment and usually do not clear impetigo. The main cost of trying them is time: the infection keeps spreading and the child stays off school for longer than they needed to.
Penciclovir cream. A prescription antiviral cream applied every two hours while awake for four days. It shortens an episode by around half a day to a day, so a little more than the over-the-counter cream and a lot less than tablets. It is a reasonable option for someone who cannot take the tablets.
Acyclovir cream. The cream version of the tablet, five times a day for four days. The virus is multiplying deep in the skin cells and traveling in a nerve, so a cream only reaches part of the problem, and the benefit is measured in hours rather than days. If you can take the tablets, take the tablets.
The usual first choice for a small number of patches, applied three times a day for about five days after the crust has been softened off. For a few sores it works as well as tablets and avoids their side effects. It is also the ointment used inside the nostrils when impetigo keeps coming back and long-term carriage in the nose is the reason.
An equally effective alternative ointment for a few small patches, used three times a day for five to seven days. Which of the two you are given depends mostly on local resistance patterns and what your country prescribes first. Neither is enough on its own once the infection is widespread.
Ozenoxacin cream. A newer antibiotic cream for the crusted form, used twice a day for five days. It is an option where resistance to the older ointments is a problem, and it works against some resistant staph. It is not widely stocked and is usually the more expensive choice.
The usual first choice, and for a cold sore it is a single day of treatment - two large doses twelve hours apart, started at the first tingle. Taken then, it shortens the episode and can stop a blister forming at all. Started after the blister is out it does much less, which is the whole argument for keeping a course at home.
An equally effective alternative, taken as a single dose at the first tingle, which suits people who will not manage a second dose later in the day. It is used where valacyclovir does not suit or is not available. It is usually the more expensive of the two.
The oldest of the antiviral tablets and the cheapest. It works, but it has to be taken five times a day for five days, which is a lot of doses for something that lasts a week anyway. The dose is lowered if your kidneys are not working well.
A low dose of the same antiviral taken every day, rather than only during an episode, for people getting roughly six or more a year. It reduces how often they happen substantially and lowers the amount of virus shed in between. The effect stops when the tablets stop, and doctors usually review it after six to twelve months.
The usual tablets or liquid when the infection is widespread, spreading fast, blistering, or the person feels unwell. A course runs about seven days, and the contagious period ends after roughly the first day of it. Finish the course even once the crusts have gone, because stopping early is one of the common reasons it comes straight back.
Used when there is a penicillin allergy, or when a swab shows resistant staph. It works well against the bacteria that cause impetigo. It upsets the stomach more than the first-choice options and, uncommonly, can cause a serious bowel infection, so any diarrhoea during or shortly after a course is worth reporting.
Reserved for adults and older children when a swab shows resistant staph, and not used in young children or in pregnancy — ask your doctor if either applies. It is a reasonable option for the age group that fits it, but for the usual patient with impetigo, a small child, it is not the drug.
Most episodes run a week to ten days. People settle into a rhythm - one or two a year, or several, and some have one episode and never another. Frequency drops with age.
Impetigo moves fast - it appears over days and, treated, clears in about a week. Untreated it usually resolves in around 2 to 3 weeks, but it spreads much further meanwhile, stays contagious throughout, and carries more risk of complications. Ecthyma, the deeper form, takes several weeks and does scar.
Herpes can occasionally spread to the eye or extensively through eczema-affected skin. Eye pain, widespread painful blisters, or exposure of a newborn requires prompt medical advice.
Cellulitis
Occasionally the bacteria get past the top layer and into the deeper tissue. The area around the sores becomes swollen, hot and increasingly painful, with redness or darkening spreading outward into normal skin, and the person often feels unwell with it. It is uncommon and it is treatable, but it needs antibiotic tablets rather than a cream, and it is a same-day problem rather than one to watch overnight.
Ecthyma — the deeper form
When the infection punches through into the layer below, it forms a punched-out ulcer under a thick, hard crust, most often on the lower legs. It is the one form of impetigo that heals slowly and does leave a scar. It is more likely where sores have been picked at, where treatment was delayed, and in people with diabetes or a weakened immune system. It needs antibiotic tablets, not an ointment.
Days off school and spread at home
Most settings ask for about 24 hours of antibiotic treatment before a child returns, with any remaining sores covered, so treating early is what gets them back soonest. The bigger cost is usually at home: without separate towels, bedding and hot washing, it works its way through the other children and sometimes the adults, and each new person starts the clock again.
Seek care for severe, frequent or persistent episodes. Eye pain or redness, widespread blisters with eczema, or illness in a newborn needs urgent assessment.
Seek treatment for suspected impetigo. Spreading redness, fever, marked pain or a newborn with blisters needs prompt assessment.
Almost certainly in childhood, from ordinary contact with someone who carried the virus - a kiss, a shared cup or spoon. Most people have no memory of it, because the first infection often causes nothing. It is not about hygiene or anything you did.
Most easily passed on from when blisters appear until the sore has fully crusted - roughly the first four to five days. Small amounts are shed when nothing is visible. Precautions matter most around newborns, eczema and anyone immune-suppressed.
Because the virus lives in one nerve, which supplies one small patch of skin. When it reactivates it travels down to that patch. Some people have two or three usual spots.
The virus stays in the body permanently, so there is no cure. But episodes usually become less frequent over the years, and daily suppressive treatment can reduce them a great deal. Plenty of people effectively stop having them.
Not while you have an active sore. Herpes simplex is dangerous in newborns in a way it is not in older children or adults. Do not kiss the baby, wash your hands before handling them, and cover the sore. If a newborn develops blisters or a fever, or becomes unusually sleepy or floppy, that is an emergency.
Less well. Antiviral tablets stop the virus multiplying, and by the time blisters are out most of that has happened. Still worth taking for a severe episode, but the benefit is in the first 24 hours.
Until about 24 hours after antibiotics start, or until the sores have fully dried and crusted if untreated, which takes far longer. That is why treatment is offered even though it would clear on its own - it cuts the contagious period from a week or more to about a day.
Most settings ask for around 24 hours of antibiotic treatment first, with remaining sores covered. Rules vary between countries, schools and nurseries, so check the policy.
Ordinary impetigo almost never scars, because it sits in the top layer of skin. Flat pink, brown or pale marks fade over weeks to months, more slowly on deeper skin tones. Ecthyma, the deeper ulcerating form, does scar, and picking raises the risk in any form.
Usually eczema that is not fully controlled, which keeps supplying broken skin. Other reasons are scratching from bites or scabies, shared towels and bedding, or long-term Staphylococcus aureus in the nose. Look at those rather than repeat the antibiotic.
Yes, though it is much less common in adults with healthy skin. The risk rises with eczema, a cut, a graze or any other break. Separate towels, handwashing after applying the ointment, and hot washing of bedding reduce the chance.
It depends how much skin is involved. A prescription ointment works as well as tablets for a few patches and avoids the side effects of oral antibiotics. Tablets or liquid are for widespread infection, rapid spread, large blisters, or an unwell child. Make that call with a doctor.
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