Cold sores and fever blisters are no different and are names for the same viral infection, which leads to painful, fluid-filled bumps or blisters, usually on and around the lips.
Cold sores are always caused by the herpes virus (usually by the herpes simplex virus type 1, and occasionally by type 2). This is the reason they are also called oral herpes.
These blisters usually heal in 1-2 weeks on their own. Antiviral medication may help in the faster healing of these lesions.
Cold sores are contagious, and one should follow good hand hygiene when taking care of them.
What are cold sores?
Cold sores are a result of a viral infection that leads to a fluid-filled bump, usually appearing on the outer side of the lip. In fact, cold sores are one of the common causes of lip blisters.
Cold sores are painful and can cause discomfort.
Fever blister vs. Cold sore
Fever blisters and cold sores are the same thing. They are just two different names for a single skin condition.
A cold sore or fever blister usually appears when someone is ill, such as when one has a fever or a cold. That is the reason they are called fever blisters and cold sores.
Both fever blisters and cold sores are not caused by fever or cold but by the herpes virus. They are also referred to as oral herpes or herpes labialis.
Causes
Cold sores are mainly caused by herpes simplex virus – type 1 (HSV-1). Sometimes, they are caused by herpes simplex virus type 2, which usually causes genital herpes.
Due to this, they are called oral herpes or herpes labialis simplex.
One can get the herpes virus by direct contact with the lesions. In fact, a lot of people get the virus while they are kids.
Many people (more than 50% of the adult population in the US) are infected by the HSV-1 virus, but not everyone shows symptoms. Once infected, this virus stays in our body and can lead to an outbreak due to some precipitating factors.
These factors include:
- Being ill, like having a cold or fever
- Immunosuppression
- Stress
- Fatigue
- Excessive sun exposure
- Injury
- Menstruation
- Dental work
- Cosmetic treatment
- Certain foods
Symptoms
Cold sores or fever blisters present with painful fluid-filled bumps, which are called blisters. These blisters may be filled with clear or cloudy fluid.
Cold sores are usually seen on the lips or their border but can also appear inside the mouth, on the nose, or cheeks. Symptoms will vary depending on whether it is the first or primary infection or a recurrent outbreak. First-time infections can have more severe symptoms and may cause sores inside the mouth.
First-time infections may be accompanied by other symptoms:
- Fever
- Sore throat
- Enlarged lymph nodes
- Fatigue
The fever blister or cold sore goes through different stages:
- First, one feels a tingling, itching, or burning sensation in the lip area.
- A few hours or a day later, small bumps or blisters will appear in the area. The area is painful and may appear red or swollen.
- These blisters can break and ooze.
- Then they start healing by crusting and scabbing.
- Finally, the scab falls off.
Duration
The recurrent outbreaks of cold sores usually last for 1-2 weeks without treatment. The first or primary infection may last longer (around 2-3 weeks).
Treatment with antivirals may help in faster healing of cold sores.
Can it spread?
Cold sores are very contagious and can spread by direct contact with the blister or sore, such as by kissing or touching. They can also spread by sharing items like towels, toothbrushes, utensils, etc.
Cold sores or fever blisters are most contagious with the first signs and symptoms – that is, itching and burning in the area.
One stays contagious until the sore heals completely, meaning that the scabbing and crusting are completely gone.
This virus can spread even if one does not have any symptoms.
Complications
In some people, the herpes infection can spread to other parts of the body:
1. Herpetic whitlow
This results in an infection of the fingertip, causing a bump or blister on the finger. It is common when someone with oral herpes sucks or bites their fingers or nails. It can also occur in dentists or someone working in the dental or medical field.
2. Herpetic sycosis (HSV folliculitis)
This occurs when the HSV virus infects the hair follicles. This can appear in men in the beard area after a close razor shave.
3. HSV keratitis
The virus can infect the eyes, resulting in conjunctivitis. It can also infect the cornea, leading to HSV keratitis. This can lead to blindness.
4. Eczema herpeticum
HSV can lead to widespread lesions in people who have skin barrier dysfunction, such as eczema. This is called eczema herpeticum.
This is a serious condition. If you have a history of eczema and you get cold sores, you should consult a doctor immediately.
5. Herpes encephalitis
The virus can inflame the brain, leading to encephalitis. This can occur in people who have a weakened immune system.
Diagnosis
Cold sores can be diagnosed clinically by a doctor after examining the lesions. In some cases, a swab may be taken and sent to a lab to test the fluid for the virus.
Treatment
The cold sores usually clear up on their own in a week or two and do not require treatment.
Home Remedies
Some over-the-counter options can help in easing the symptoms of cold sores:
- Cold compress: A cold compress may help with pain and itching.
- Over-the-counter ointments or creams: Lip ointments or moisturizers can moisturize the area and prevent dryness, especially during the scabbing stage.
- Cold sore balms: Several over-the-counter balms like Carmex are meant to reduce the symptoms. Some of these contain benzocaine, which can numb the area and reduce the pain. However, they do not reduce the healing time.
- Cold sore patches: Hydrocolloid gel patches for cold sores may help in protecting the healing area.
- Abreva (Docosanol): This is an over-the-counter cream that contains an antiviral – docosanol. It may help in faster healing of cold sores. One should start using it at the very first signs or symptoms of a fever blister.
- Sunscreen: One should protect the lips from the sun by using a broad-spectrum sunscreen. If chemical sunscreen stings your skin, it’s best to opt for all-mineral or physical lip sunscreen.
- Painkillers: Over-the-counter oral pain medication like acetaminophen can ease discomfort.
- Hand hygiene: Make sure to wash your hands properly every time you touch your cold sore or apply any cream. This will prevent the spread of the virus to other parts of the body.
- Avoid acidic, spicy, or salty foods: Avoid foods that may cause a burning sensation when they touch the area with cold sores. These include salty and spicy food, and acidic food like tomatoes, oranges, etc.
- Stay hydrated: Drink plenty of fluids to prevent dehydration.
Prescription medications
In severe or recurrent cases, or if someone has a weak immune system, antiviral medications may be prescribed for faster healing of the sore and for preventing complications.
They can either be in the form of topical creams, such as Denavir (penciclovir cream), or oral antiviral medications such as Acyclovir, Valacyclovir, or Famciclovir.
In some cases, an intravenous (IV) medication may be recommended depending on the severity and underlying immune status of a person.
Antiviral medications give the best results when started within 48 hours of the onset of symptoms.
When to see a doctor
One should see a doctor if:
- The sores or blisters do not heal or get worse.
- There is any eye irritation or sores present near the eyes.
- There are systemic symptoms like high fever, headache, dizziness, or confusion.
- One has a weak immune system.
- One has a history of eczema.
- If you are not sure what’s causing the blister on your lip.
Prevention
Once a person is infected, the virus stays in the body. However, a few precautions can decrease the chances of a recurrent outbreak and prevent the spread to others:
- Practice good hygiene.
- Protect your lips from the sun and use sunscreen.
- Eat a healthy diet and get good rest to avoid fatigue.
- Do not share personal items with someone who has a cold sore.
- Do not kiss someone with a cold sore.
Key points
Cold sores, also known as fever blisters or oral herpes, are painful fluid-filled bumps that usually appear on and around the lips, but these can also involve other areas of the face or oral cavity.
Cold sores are usually caused by the herpes simplex virus (HSV) type 1. They are very contagious, and one should be careful when handling them to prevent the spread to other parts of the body.
They usually heal on their own; however, in some cases, antiviral medications may be prescribed. One should see a doctor if the blisters don’t heal or if one has a weak immune system.
Read more:
- Cold sores pictures and symptoms
- Cold sores stages, with pictures
- Canker Sore vs Fever Blister (Cold Sore)
- Itchy Bumps Filled with Clear Liquid (Blister Rashes)
References
- Saleh D, Yarrarapu SNS, Sharma S. Herpes Simplex Type 1. [Updated 2022 Aug 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan.
- Oakley A. Herpes Simplex. DermNet.
Disclaimer: This blog post is for information purposes only and does not replace medical advice.