Cold sores are small, blister-like lesions which usually appear around the mouth. They’re caused by the herpes simplex viruses. The strain that usually causes them around the mouth is herpes simplex type 1 (HSV-1). In rare cases, cold sores can also be caused by the herpes simplex type 2 virus (HSV-2). This can happen as a result of having oral sex with a man or woman who has genital herpes. While they often go away on their own within a week or two, they can be painful and unsightly.
Symptoms of cold sores
In many cases of herpes simplex infections, there are no symptoms of the primary infection, and you may not even know you have contracted the virus unless you get an outbreak of cold sores sometime later. However, if there are symptoms with a primary infection, they can be quite severe.
Symptoms of the primary infection
In most cases of primary infection of the cold sore virus, there will not be any noticeable signs or symptoms. However, if there are symptoms, they are most likely to occur in children under the age of five, and they can be quite severe. They include:
- Swollen and irritated gums, with small painful sores in and around your mouth (known as herpes simplex gingivostomatitis).
- Sore throat and swollen glands.
- Excess salivation (producing more saliva than normal).
- Fever.
- Dehydration (a lack of water in the body).
- Nausea.
- Headaches.
If you or your child develops herpes simplex gingivostomatitis, it can last between 7-14 days, and it may take up to three weeks for the sores to heal. However, gingivostomatitis does not often recur after the primary infection. It is usually young children who get gingivostomatitis, although it is possible for adults to get it as part of a primary infection.
However, if an adult has a primary infection it usually presents itself as pharyngotonsillitis (a sore throat and swollen tonsils), or a glandular fever-like illness. The symptoms will usually be a sore throat, with or without swollen glands. You may also have halitosis (foul-smelling breath) and painful sores in and around your mouth, which can develop into ulcers with grey or yellow centres.
If someone has been infected with the herpes simplex virus at an early age, it may be triggered periodically in later life which can cause recurring bouts of cold sores. After the primary infection, the symptoms are usually reduced to just the cold sores themselves.
Symptoms of the recurrent infection (outbreaks of cold sores)
Recurrent infections are usually shorter and less severe than the primary infection. The only symptom is usually the outbreak of cold sores themselves, although in some cases you may also have swollen glands.
An outbreak of cold sores usually starts with a tingling, itching or burning sensation around your mouth. Small fluid-filled sores then appear, most commonly on the edges of your lower lip.
If you have frequent recurrent infections, you may find that your cold sores occur in the same place every time. Your cold sores may grow in size and cause irritation and pain. They may weep and eventually grow a crust or scab within 48 hours of the initial tingling sensation.
Most cold sores disappear within 7-10 days without treatment, and they generally heal without scarring.
Causes of cold sores
Cold sores are caused by the herpes simplex virus (HSV). There are two types of herpes simplex virus: HSV-1 and HSV-2. Cold sores are typically caused by HSV-1, although they can also be caused by HSV-2. The virus is highly contagious and can be spread through close personal contact, such as kissing, or through the sharing of utensils, towels, or other personal items. Cold sores can also be spread through oral sex.
People who have been infected with the herpes simplex virus can experience outbreaks of cold sores from time to time. Outbreaks can be triggered by various factors, including stress, fatigue, illness, sunlight, or hormonal changes. Once a person has been infected with the virus, it remains in their body for life and can cause outbreaks of cold sores at any time.
Diagnosing cold sores
Diagnosing cold sores can often be done based on their appearance and symptoms. However, a healthcare provider may perform a physical examination and take a medical history to help confirm the diagnosis. In some cases, a sample of fluid from the cold sore may be taken and tested in a laboratory to confirm the presence of the herpes simplex virus.
A healthcare provider may also perform a Tzanck test, which involves taking a sample of cells from the blister and looking at them under a microscope to confirm the presence of the virus. In some cases, a blood test may be performed to detect antibodies to the herpes simplex virus. This can help confirm a previous infection and determine which type of herpes simplex virus is responsible for the cold sore outbreak.
It is important to receive a proper diagnosis for cold sores so that appropriate treatment can be started and to rule out other conditions that may cause similar symptoms.
Treating cold sores
There is no cure for cold sores, but there are treatments available to help manage symptoms and reduce the duration of outbreaks. The following are some common treatments for cold sores:
- Antiviral medications: Antiviral medications, such as acyclovir (Zovirax), valacyclovir (Valtrex), and famciclovir (Famvir), can help reduce the severity and duration of outbreaks. These medications can also reduce the risk of transmission to others.
- Topical creams and ointments: Topical creams and ointments, such as docosanol (Abreva) and penciclovir (Denavir), can help reduce the pain and duration of outbreaks.
- Pain relievers: Over-the-counter pain relievers, such as acetaminophen (Tylenol) and ibuprofen (Advil), can help relieve pain and reduce inflammation.
- Cold compresses: Applying a cold compress to the affected area can help reduce pain and swelling.
- Lifestyle changes: Making lifestyle changes, such as reducing stress, getting enough sleep, and avoiding triggers, can help reduce the frequency and severity of outbreaks.
It is important to start treatment as soon as possible after the first symptoms of a cold sore appear. This can help reduce the severity and duration of the outbreak. A healthcare provider or doctor can help determine the best course of treatment for an individual based on their specific needs and medical history.
Complications of cold sores
Infections caused by the cold sore virus are often mild and usually heal without the need for treatment. However, in rare cases they can cause complications, particularly in people with damaged immune systems, such as those undergoing chemotherapy and those who are HIV positive.
The possible complications of the cold sore virus are detailed below.
Dehydration: Dehydration is a lack of water in the body, and it may occur as a result of the pain caused by an infection of the cold sore virus. Cold sores, or herpes simplex gingivostomatitis, can be painful, and it’s easy to neglect your need to drink plenty of fluids. Young children are particularly at risk of becoming dehydrated.
Herpetic whitlow: It is possible for the cold sore virus to spread to other parts of your body. This is known as a secondary infection. Herpetic whitlow is a secondary infection of the cold sore virus, which causes painful sores and blisters on your fingers. It can occur when the cold sore virus comes into contact with a cut or graze on your hand, and enters your skin. However, it can be easily treated using antiviral medication.
Herpetic keratoconjunctivitis: Herpetic keratoconjunctivitis is a secondary infection of the cold sore virus which affects your eyes. If the virus comes into contact with your eyes, it can cause inflammation of your eye area, and sores to appear on your eyelids. However, it can usually be easily treated using antiviral medication available from a specialist eye doctor.
If left untreated, herpetic keratoconjunctivitis can cause your cornea (the transparent layer over your eye) to become infected, which can eventually lead to blindness. It is very important not to touch your eyes when you have an active cold sore. However, if you must touch your eyes, for example to remove contact lenses, make sure you wash your hands thoroughly first.
Encephalitis: Encephalitis is a serious condition in which the brain becomes swollen, possibly causing brain damage and even death. In severe cases it is caused by the cold sore virus spreading to the brain, but this is very rare. Encephalitis can be treated by injecting antiviral drugs such as aciclovir into the veins.
Preventing cold sores
However, if you or your child have a cold sore, there is no need for you to stay away from work, or for your child to miss school. Similarly, if you or your child have a primary infection, you do not need to keep yourselves away from work, nursery or school, unless you’re feeling unwell.
Minimising the spread of the infection
Measures that you can take to help minimise the spread and recurrence of the cold sore virus are detailed below.
- Try to avoid touching your cold sores, unless you are applying a cream. Creams should be dabbed on gently rather than rubbed in, as this can damage your skin further.
- Always wash your hands before and after applying cream, and after touching the affected area.
- Do not share creams or medications with others because this can cause the infection to spread.
- Do not share items that come into contact with the affected area, such as lipsticks or cutlery.
- Avoid kissing and oral sex until your cold sores have completely healed.
- If you have a cold sore, be particularly careful around newborn babies, pregnant women and people with a low immune system, such as those who have been undergoing chemotherapy, or those with HIV.
Preventing recurrent outbreaks of cold sores
If you know what usually triggers your cold sores, try to avoid these triggers if possible. For example, a sun block lip balm (SPF 15 or higher) may help to prevent cold sores triggered by bright sunlight.
The following are some common treatments for cold sores:
- Antiviral medications: Antiviral medications, such as acyclovir (Zovirax), valacyclovir (Valtrex), and famciclovir (Famvir), can help reduce the severity and duration of outbreaks. These medications can also reduce the risk of transmission to others.
- Topical creams and ointments: Topical creams and ointments, such as docosanol (Abreva) and penciclovir (Denavir), can help reduce the pain and duration of outbreaks.
- Pain relievers: Over-the-counter pain relievers, such as acetaminophen (Tylenol) and ibuprofen (Advil), can help relieve pain and reduce inflammation.
- Cold compresses: Applying a cold compress to the affected area can help reduce pain and swelling.
- Lifestyle changes: Making lifestyle changes, such as reducing stress, getting enough sleep, and avoiding triggers, can help reduce the frequency and severity of outbreaks.
FAQs
Are cold sores contagious?
Yes, cold sores are highly contagious. Cold sores are caused by herpes simplex virus type 1 (HSV-1), which can be easily spread from person to person through direct contact with the sores, such as kissing or sharing utensils, towels, or other personal items. The virus can also be spread when there are no visible sores present, so it is important to practice good hygiene and to avoid close contact with individuals who have active cold sores. To minimize the spread of the virus, it is also important to wash your hands frequently and to avoid touching your face, especially your mouth and eyes.
How long do cold sores last?
Cold sores usually last anywhere from 7 to 10 days, although they can persist for up to two weeks. The length of time a cold sore lasts can depend on several factors, including the individual’s immune system, the type of herpes simplex virus causing the infection, and whether the person has had cold sores before. In general, the first outbreak of cold sores is usually the worst and lasts the longest, while subsequent outbreaks tend to be milder and shorter in duration.
The cold sore will typically go through several stages, starting with the tingling or burning sensation that occurs before the blister appears. This is followed by the appearance of small, fluid-filled blisters, which eventually break open, ooze, and then crust over. As the crust begins to heal and fall off, the sore will start to disappear, although some redness and itching may persist for a few more days.
It is important to remember that the herpes simplex virus remains in the body even after the cold sore has healed, and it can reactivate and cause another outbreak at any time, especially during periods of stress, illness, or hormonal changes.
What is the difference between a cold sore and a canker sore?
Cold sores and canker sores are two distinct types of oral lesions that can cause pain, discomfort, and embarrassment. Cold sores are caused by the herpes simplex virus type 1 (HSV-1), which is highly contagious and can be spread through close personal contact whereas canker sores are small, shallow ulcers that occur inside the mouth, such as on the tongue, gums, or inside of the cheeks. They are not caused by a virus and are not contagious. The exact cause of canker sores is not known, but they are thought to be related to stress, injury to the mouth, hormonal changes, or an autoimmune response. Canker sores are usually round or oval in shape, with a white or yellow center and a red border.