The Differences Between Cold Sores And Impetigo

One of the most common questions patients ask their doctor about impetigo and cold sores is how to differentiate between them. Although they're both skin conditions that cause blisters, some key differences distinguish impetigo from cold sores, which can help you determine which condition you may have if you develop blisters on your skin. Read on to find out how they differ. 

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Cold sores are usually caused by the herpes simplex virus. They mostly tend to occur on or around the mouth but can affect other parts of the body. 

Impetigo is caused by the staphylococcus or streptococcus bacteria and tends to occur on exposed skin such as arms or legs or around the nose and mouth. 

Both conditions are highly contagious, and sometimes cold sores, which cause blisters and breaks in the skin, can lead to impetigo as a secondary infection. Therefore, it is possible to have both conditions at the same time.

What is impetigo?

Impetigo, also known as school sores, is a bacterial skin infection that is highly contagious. The bacteria spreads through contact with an infected person, their clothes, or contaminated objects. The bacteria infects the skin, either through a break or cut in the skin or through damaged skin by another condition like scabies, head lice, eczema, or cold sores. 

Symptoms of impetigo include sores on the skin that can be painful and itchy and turn into yellow-colored scabs. Treatment typically involves topical or oral antibiotic medication as well as good wound care, which also helps prevent the spreading of the infection to other people. 

Impetigo symptoms

 Impetigo is characterized by red bumps and blisters that break and result in yellow crusting or oozing pus. The infection may be mistaken for a cold sore because of its blister-like symptoms, but it should not be confused with herpes, which is caused by a virus. 

Who is at risk?

While everyone is at risk of getting a cold sore, some people are more at risk for impetigo than others. Children between two and five are most likely to contract impetigo, though other risk factors such as poor hygiene and existing scabies infections can also increase the likelihood of an infection. People who have weak immune systems are also at risk. 

The underlying cause of impetigo differs from other skin rashes

Unlike most common skin rashes in children, which are caused by dry skin, allergies, or diaper rash, impetigo is caused by bacteria. It appears as red spots that look like pimples and can quickly spread to other parts of the body. Impetigo is caused by one of two types of bacteria (group A Streptococcus or Staphylococcus aureus) and has a different appearance.

Impetigo is more common in children than in adults

Impetigo is most common in children but can also be passed on to adults. It is transmitted by direct contact with someone who has it or by touching contaminated objects such as towels, sheets, clothes, and toys.

Impetigo is extremely contagious, which not all skin rashes are

Not all skin rashes are contagious, but impetigo is highly contagious. It can spread through close contact with an infected person or by touching objects that have been in contact with an outbreak. One of the main symptoms of impetigo is fluid-filled blisters on the skin. These blisters will often rupture, and the bacterial fluid from these blisters can be highly contagious, so it's important to avoid contact with them to prevent infection.

Potential complications from impetigo

Impetigo causes pimples or blisters with yellow crusts to form on the skin. But in very rare cases, it can also have serious consequences, such as cellulitis, guttate psoriasis, scarlet fever, and certain types of sepsis.  

What is a cold sore?

Cold sores are unpleasant fluid-filled blisters that are usually caused by the herpes simplex virus type 1 (HSV-1). HSV-1 causes cold sores around the mouth or lips from time to time, but it can also be seen in other parts of the body. Sometimes, cold sores can be caused by the herpes simplex virus type 2, which is usually the cause of genital herpes. 

What are the symptoms of cold sores?

Since herpes simplex (the virus which causes cold sores) lies dormant in nerve cells, some people may never develop any symptoms from the virus, while others will have outbreaks of cold sores periodically for the rest of their lives.

The symptoms of a cold sore usually start off as a tingling or burning sensation on or around the lips, before small fluid-filled blisters appear, which may be painful and itchy. These will eventually break open and scab. A cold sore usually lasts 7–10 days and heals without leaving any scars. What causes cold sores?

Cold sores are caused by the herpes simplex virus. When inactive, the virus lies dormant in a group of nerve cells. While some people never develop any symptoms from the virus, others will have periodic outbreaks of infections. The virus is highly contagious and can be spread from person to person through kissing or sharing objects such as drinking glasses or utensils. Though this condition cannot be cured, it can be managed with over-the-counter medications. 

Impetigo or cold sores?

It can be difficult to tell a cold sore from impetigo, but these two skin conditions are not the same. While both conditions are contagious and manifest similar symptoms, like redness and itching, they are caused by different bugs.

Herpes simplex virus 1 usually causes cold sores. Most adults infected with HSV1 have had the strain since childhood through exposure to someone with the virus, often through a kiss or sharing personal items, like cutlery or towels. Impetigo is caused by the bacteria streptococcus and staphylococcus and is seen more often in children than in adults.

Most of the time, cold sores are found around the lips, whereas impetigo can occur anywhere on the body. Cold sores also usually heal within a few days to a week, while impetigo can take several weeks to heal and may require antibiotic treatment. 

If there is uncertainty about what is causing your skin condition, the doctor can easily order a skin swab from the blisters, which will indicate what is driving the infection. 

Treatment for impetigo

It is important to take note to keep the area infected with impetigo covered so you don't accidentally spread the disease to other areas of your body or other people.

Impetigo is a highly contagious bacterial skin infection which should be taken seriously and treated as soon as possible. While treating cold sores usually involves topical medications like anesthetic creams or antiviral medication, such as acyclovir, valacyclovir, and famciclovir, impetigo can be treated with oral or topical antibiotics applied to the infected area. These treatments can also help alleviate pain and shorten healing time.

Impetigo can be a complication of another skin problem 

Impetigo caused by other skin problems will typically start as an open sore or lesion, which is more susceptible to bacterial infection. Once the damaged skin is infected, it will often become irritated and red, with weepy blisters forming that will eventually crust over. 

Prevention of cold sores and impetigo

Cold sores are usually caused by a virus, whereas impetigo is an infection caused by bacteria. Both are very contagious and spread easily through skin-to-skin contact. The best way to avoid getting an infection is to wash your hands after coming into contact with someone else's saliva or skin and before eating. 

There is no cure for cold sores. The best way to prevent them is to avoid triggers such as stress, sunburn, fever, or physical injury. 

The lowdown

A cold sore is a type of skin infection caused by a virus called herpes simplex. It is often confused with impetigo, which is an infection caused by bacteria. The best way to tell them apart is to look at where they occur on the body. Impetigo usually occurs on a child's face or arms and legs, while cold sores are found directly on the lips, around the mouth, or nose. 

Another way to tell them apart is to consult your healthcare provider, who can provide a swab test and confirm what is causing the sores.

Frequently asked questions

How do I know if I have a cold sore or impetigo? 

Cold sores appear as little white or yellow blisters on red bumps or bruises on your lips and face, while impetigo forms in a much larger cluster and can occur on arms and legs as well. It is best to consult a doctor to know for sure. 

What can be mistaken for impetigo?

These red bumps on your skin could be confused with a number of conditions, including chicken pox, contact dermatitis, skin conditions like eczema or psoriasis, and even scabies. Scabies is caused by a parasite that burrows under your skin and causes an itchy rash. 

How does impetigo look at the start?

Impetigo usually starts as small red spots or blisters on your skin. If you scratch impetigo, it can spread across your skin and cause larger sores to develop. You may also have other symptoms along with your impetigo rash, such as a fever.

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