If a tongue sore is confirmed to be caused by the herpes simplex virus, treatment may include an antiviral such as oral aciclovir or valaciclovir. Starting treatment early, ideally within 24 to 48 hours of symptoms appearing, may help reduce the severity and duration of an outbreak. A healthcare professional can confirm the diagnosis and advise on the most appropriate treatment.
Most cold sores appear on or around the lips, but they can also develop inside the nose, on the tongue, or elsewhere on the face. If you are pregnant, you may have extra questions about which treatments are considered safe. For adults in the UK with cold sores in these less common and more sensitive areas, this guide explains what may cause them, how to recognise them, which antiviral treatments may be suitable, what self care measures may help ease discomfort, when it is important to seek medical advice, and what current UK guidance says about treatment during pregnancy and through EveryDayMeds.
Treatment suitability, including which medicine and what dose may be appropriate, depends on an individual clinical assessment. This guide is for general information only. Your prescriber will determine the most appropriate treatment for your individual situation.
What Causes Cold Sores: The Role of Herpes Simplex Virus
Cold sores are most commonly caused by herpes simplex virus type 1 (HSV 1), although herpes simplex virus type 2 (HSV 2\) can also occasionally cause oral infections. The virus stays dormant in the body after the initial infection and can reactivate from time to time, often triggered by stress, illness, sun exposure, or a weakened immune system. The first sign is usually a tingling, burning, or itching sensation, followed by a blister or sore that typically heals within 7 to 10 days.
Cold Sores Inside the Nose
Cold sores inside the nose are less common than cold sores around the lips but can be more uncomfortable because the lining of the nose is sensitive, and swelling may make it harder to breathe through the nose. Early symptoms are similar, with a burning or tingling sensation followed by pain and swelling, but the sore itself may be less visible than a cold sore on the outside of the lips.
A note on eye involvement: because the nose is close to the eye, a cold sore that spreads towards or around the eye needs prompt medical attention. A herpes simplex infection affecting the eye requires urgent medical assessment and should not be self managed. Seek medical advice as soon as possible if you notice eye redness, pain, sensitivity to light, or changes in your vision alongside a cold sore inside the nose.
Cold Sores (Fever Blisters) on the Tongue
A sore on the tongue is less typical of a recurrent cold sore, which usually appears on the outer lip or the skin around the mouth rather than inside the mouth. Tongue sores can have several possible causes, including oral herpes or mouth ulcers such as canker sores. Canker sores are different from herpetic lesions, so it is important to have a tongue sore properly assessed rather than assuming it is a cold sore, especially if it is the first time you have experienced one in that area.
Tongue sores can also be painful, particularly when eating or speaking.
If a healthcare professional confirms that the sore is caused by the herpes simplex virus, antiviral treatment may be considered. Oral tablets are generally more practical than topical creams for sores inside the mouth. Topical anaesthetics may also help numb the pain. Self care measures may help ease discomfort, including warm salt water rinses, sucking on ice chips, and avoiding spicy or acidic foods that may irritate the sore.
Treatment Options
Aciclovir is an antiviral medicine that works by interfering with herpes virus replication. When started early, ideally within 24 to 48 hours of the first tingling or burning sensation, it may help reduce the severity and duration of a cold sore outbreak. It is available as tablets for a systemic effect or as a 5% cream for localised topical use. Docosanol is another over the counter treatment that may be used for cold sores.
Valaciclovir is converted into aciclovir in the body and may be prescribed because it offers a more convenient dosing schedule for some people.
The exact dose and treatment duration will be determined by your prescriber based on your symptoms, the location and severity of the outbreak, and your medical history. This is not something that should be worked out using general guidance. Follow the dose and treatment duration on your prescription and patient information leaflet exactly. For cold sores on the outside of the mouth, topical creams may be suitable, while oral treatment is often more practical for sores inside the mouth.
Supportive Self-Care
Alongside prescribed treatment, some general self care measures may help improve comfort:
- Keep the affected area clean and avoid touching or picking at it, as this may help reduce the risk of spreading the virus or developing a secondary bacterial infection. If the sore is inside the mouth, maintaining good oral hygiene may also help.
- Applying a cold compress to the outside of the affected area may help reduce swelling and ease discomfort.
- Over the counter pain relief, such as paracetamol, may help. Always take it as directed on the packaging.
- Use separate towels and avoid close contact with other people while the sore is active, as this may help reduce the risk of spreading the virus. Cold sores can be contagious from the early tingling stage until the sore has completely healed. They can spread through skin to skin contact and saliva and are most contagious when the blisters burst.
Cold Sores During Pregnancy
Finding out you have a cold sore while pregnant can be worrying, but current UK evidence is generally reassuring about the use of these medicines during pregnancy when they are clinically indicated. According to the available UKTIS information, current data do not suggest that aciclovir or valaciclovir use during pregnancy increases the risk of congenital malformations. UK guidance also supports the use of aciclovir during pregnancy for certain viral infections when clinically indicated. The Royal College of Obstetricians and Gynaecologists (RCOG) recommends that aciclovir should be considered for pregnant women with a first episode of herpes. Cold sores often heal within around 7 to 14 days, although this can vary between individuals. If you think you have a first herpes simplex infection during pregnancy, it is important to seek prompt assessment from your healthcare provider or maternity team.
Treatment decisions during pregnancy should always be made with your GP or midwife rather than independently. They will consider your individual circumstances, including which trimester you are in and whether it is a first or recurrent outbreak.
First time vs recurrent outbreaks. A first herpes simplex infection during pregnancy is generally considered more significant than a recurrent outbreak because it can be more severe and, depending on when it occurs and the type of infection, may require closer monitoring. Although first infections are less common in adults, they can be more severe. If this is your first cold sore during pregnancy, contact your GP or midwife rather than waiting to see if it improves on its own.
Near delivery. Recurrent outbreaks close to your due date may be discussed with your maternity team as part of your birth planning because they can be relevant to reducing the risk of passing the virus to your baby. Prompt assessment is especially important if your symptoms suggest a new herpes simplex infection close to delivery because of the risk of neonatal herpes.
Topical vs oral treatment. Both topical aciclovir cream and oral aciclovir tablets may be used during pregnancy when clinically appropriate. The most suitable treatment will depend on your individual circumstances and should be decided by your healthcare professional. Stress, changes to the immune system, and fatigue during pregnancy may also contribute to cold sore outbreaks.
When to Seek Medical Advice for Cold Sore Symptoms
Contact a doctor or pharmacist promptly rather than waiting if:
- A cold sore is spreading towards or around your eye.
- You notice eye redness, pain, sensitivity to light, or changes in your vision alongside a cold sore.
- You have a weakened immune system and develop a herpes outbreak.
- You are pregnant and experiencing your first ever cold sore outbreak.
- Your symptoms are severe, continue to spread, or you notice possible signs of a secondary bacterial infection, such as increasing redness, warmth, or pus.
- A cold sore lasts for more than two weeks.
- You have frequent cold sore outbreaks.
Quick Takeaways
- The location of a cold sore does not necessarily change the underlying cause. Cold sores inside the nose and some sores inside the mouth may be caused by HSV 1, although tongue sores can have other causes. Cold sores near the nose carry an additional risk if they spread towards the eye, and tongue sores should be assessed rather than assumed to be cold sores.
- Early treatment may be more effective. Starting antiviral treatment within 24 to 48 hours of the first symptoms may help reduce the severity and duration of an outbreak.
- Pregnancy does not always rule out treatment. UKTIS and RCOG guidance support the use of aciclovir or valaciclovir during pregnancy when clinically indicated, but any treatment decision should be made with your GP, midwife, or maternity team.
- The right dose and treatment duration should always be decided by your prescriber based on your individual circumstances.
How to Get Treatment Through EverydayMeds
EveryDayMeds' online consultation asks about your symptoms, where they are located, and your relevant medical history, including whether you are pregnant, if applicable. A registered prescriber will use this information to determine whether treatment is appropriate. The consultation typically takes under two minutes to complete, and prescriber review is usually completed within 24 to 48 hours. If your treatment is approved, your order will be dispatched in discreet packaging using tracked delivery.
