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Impetigo: Symptoms, causes and treatment

What is impetigo?

Impetigo is a highly contagious bacterial skin infection causing blisters and sores.

Impetigo mainly affects children, often on the face, especially around the nose and mouth, and sometimes on the arms or legs.

Picture of Impetigo

The two types of impetigo are bullous impetigo and non-bullous impetigo.

Bullous impetigo causes large fluid-filled blisters that are painless.

Non-bullous impetigo is the more contagious form of the condition causing sores that burst leaving a yellow-brown crust.

If the impetigo affects an otherwise healthy area of skin, it is called primary impetigo. Impetigo resulting from another skin condition is called secondary impetigo.


Causes of impetigo

The most common cause of impetigo is Staphylococcus aureus. However, another bacterial cause is the group A streptococcus. These bacteria lurk everywhere. It is easier for a child with an open wound or fresh scratch to contract impetigo. Other skin-related problems, such as eczema, body lice, insect bites, fungal or bacterial infections, and various forms of dermatitis can make a person susceptible to impetigo.

Most people get this highly infectious disease through physical contact with someone who has it, or from sharing the same clothes, bedding, towels, or other objects. The very nature of childhood, which includes much physical contact and large-group activities, makes children the primary victims and carriers of impetigo.

In extreme cases, the infection invades a deeper layer of skin and develops into ecthyma, a deeper form of the condition. Ecthyma forms small, pus-filled ulcers with a crust much darker and thicker than that of ordinary impetigo. Ecthyma can be very itchy, and scratching the irritated area spreads the infection quickly. Left untreated, the ulcers may cause permanent scars and pigment changes. The gravest potential complication of impetigo is post-streptococcal glomerulonephritis, a severe kidney disease that occurs following a streptococcal infection in about 2% to 5% of cases, mainly in children.

What are the symptoms of impetigo?

  • A small patch of blisters that after a few hours break into red, moist areas that ooze or weep fluid; appears mainly on the face, but also on exposed areas of the arms and legs.
  • In a few days, the formation of a golden or dark-yellow crust resembling grains of brown sugar occurs. The infection may continue to spread at the edges of the affected area or affect other skin areas.

Seek medical advice if:

You have sores or a rash that worsens or becomes more uncomfortable. Impetigo needs prompt medical attention, especially if accompanied by any of the following:

  • Small, very itchy, pus-filled ulcers, with a dark brown crust. This indicates ecthyma, an ulcerated form of impetigo that penetrates deep into the skin. If left untreated, it may cause scarring and permanent changes in pigmentation.
  • Urine changes, body swelling, nausea, or headache develop. These could be signs of glomerulonephritis, a kidney disease caused by bacterial toxins.

Sores associated with impetigo may be mistaken for herpes, a viral infection. Impetigo spreads faster, never develops inside the mouth, and is rarely confined to one area of the body. If in doubt, seek medical advice for an accurate diagnosis.

WebMD Medical Reference

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