Impetigo is a contagious, superficial infection of the skin caused by Streptococcus and Staphylococcus bacteria.

The infection tends to develop in areas of the skin which have already been damaged through some other mechanism, such as – insect bite, a burn, or vesicle from chickenpox.

There are two main types:

  • bullous (30 percent of cases);
  • nonbullous (70 percent of cases).

In the United States, approximately 10 percent of pediatric patients presenting with dermatologic complaints are diagnosed with impetigo.


The sores can be anywhere on the body, however, they are commonly found on the face near the nose and mouth, or on the legs and arms.

Common symptoms include:

  • a collection of blisters forms;
  • the skin reddens and itches;
  • the area develops a wet-looking crust.


Untreated, it can lead to deeper infection, particularly if it is caused by staph. Complications may include:

  • septicemia (body-wide response to the infection);
  • deeper infection of your skin;
  • lung infection;
  • infection of the lymphatic system;
  • joint infection;
  • bone infection;
  • bacteria in the bloodstream.


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Impetigo caused by A streptococci are most common in children ages 2 to five. However, when the infection is caused by the bacterium Staphylococcus aureus, it affects children of all ages.

Note – most sufferers are no longer contagious once their sores have dried and healed or after 48 hours of treatment.

Risk Factors

Factors which may increase your chances of developing this infection include:

  • lice infections which cause scratching, like – head lice, scabies, or pubic lice;
  • touching a person with impetigo;
  • chickenpox;
  • touching the clothing, sheets, towels, or other personal items which belong to an individual with impetigo;
  • scratches, cuts, insect bites, or other injuries to the skin;
  • poor hygiene, especially dirty fingernails and unwashed hands;
  • a tendency to have skin problems, like – poison ivy, eczema, or a skin allergy;
  • weakened immune system;
  • poor health;
  • summer season;
  • warm, humid environment;
  • contact sports, like – wrestling and football;
  • crowded settings where there is direct person-to-person contact, like – the military and schools.


Healthcare professionals commonlly diagnose this infection by looking at the distinctive sores. In addition, they may take a tiny sample of skin which will be sent to a laboratory to see which pathogenic bacteria is causing the infection.


It is typically treated with an antibiotic cream. However, if it doesn’t clear up, your healthcare professional might give you an antibiotic to swallow.

Note – untreated impetigo usually resolves within one month without scarring.


Prognosis for a patient with impetigo is excellent and most patients recover completely and uneventfully.


Prevention of impetigo involves good personal hygiene:

  • wash wounds like – scratches, cuts, or insect bites, with water and soap;
  • bathe daily with soap and water;
  • do not let your children have close contact or play with someone who may have the infection;
  • change and wash clothing often;
  • wash your hands, face, and hair regularly;
  • keep fingernails short and clean;
  • do not share clothes, towels, or sheets;
  • if caring for someone with the infection, be sure to wash your hands each time you touch the affected individual.

Cold Sore

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Cold sores, also known as fever blisters, are red, fluid-filled blisters which form near the mouth or on other areas of the face. Cold sores are caused by the herpes simplex virus.

Once you’ve become infected with herpes simplex virus, it stays in your body for life. Most of the time the virus is dormant or inactive.

Over 3.8 billion people under the age of 50 are infected with herpes simplex virus type 1, according to the World Health Organization.

There are two types of herpes simplex virus:

  • Type 1 herpes virus – it infects more than half of the United States population by the time they reach their 20s. It usually causes oral herpes.
  • Type 2 – it usually affects the genital area.

Note – it is possible for HSV-2 to cause sores on the mouth and for HSV-1 to cause sores on the genitals.


Cold sores usually develop as follows:

  • tingling and itching 1 or 2 days before the cold sore appears;
  • a collection of small blisters forms;
  • the blisters burst after several days;
  • the site develops a crust;
  • the crust falls off after approximately 10 days.


  • erythema multiforme;
  • dehydration, particularly in children;
  • corneal dendritic ulcers (ocular herpes simplex);
  • atrophy and scarring;
  • meningitis;
  • secondary bacterial infection;
  • herpes encephalitis.


Cold sores are caused by the herpes simplex virus. After you get infected, the virus stays in your body for the rest of your life.

Risk Factors

Factors that can trigger the virus to reactivate and cause future cold sore outbreaks include:

  • changes in the immune system;
  • fever;
  • viral infection;
  • hormonal changes;
  • exposure to sun and wind;
  • fatigue;
  • emotional stress.


Symptoms of tingling pain followed by the typical blisters which crust around the mouth and nose are commonlly sufficient to make the diagnosis.


Antiviral creams applied directly to the sores shorten the healing time by about 24 hours.


Cold sores typically heal within 7 to 10 days, without scarring.


If you have a cold sore, be sure to wash your hands after touching it. Furthermore, to reduce the chances of spreading the infection, it is essential to avoid:

  • close contact with people with suppressed immune systems;
  • sharing toothbrushes;
  • close contact with children with eczema or burns;
  • sharing drinking bottles or glasses;
  • kissing others;
  • sharing cutlery;
  • close contact with newborn and young babies;
  • sharing towels or other personal items.

Bottom Line – Impetigo vs Cold Sore

Impetigo is a skin infection which tends to afflict mainly children. It is commonly found in environments, like – nurseries and schools, where the infection can easily be spread. It’s most often caused by the bacteria Staphylococcus aureus.

Cold sores are small, painful blisters which usually form near the mouth. The virus that causes cold sores is known as the herpes simplex virus.

In conclusion, these infections have different causes – one is caused by a bacterium, wheres the other is caused by a virus. Also, impetigo is most common in children, whereas cold sores affect people of all ages.