Symptoms and causes

Symptoms

Classic signs and symptoms of impetigo involve red sores that quickly rupture, ooze for a few days and then form a yellowish-brown crust. The sores usually occur around the nose and mouth but can be spread to other areas of the body by fingers, clothing and towels. Itching and soreness are generally mild.

A less common form of the disorder, called bullous impetigo, may feature larger blisters that occur on the trunk of infants and young children.

A more serious form of impetigo, called ecthyma, penetrates deeper into the skin — causing painful fluid- or pus-filled sores that turn into deep ulcers.

When to see a doctor

If you suspect that you or your child has impetigo, consult your family doctor, your child's pediatrician or a dermatologist.

Causes

You're exposed to the bacteria that cause impetigo when you come into contact with the sores of someone who's infected or with items they've touched — such as clothing, bed linen, towels and even toys.

Risk factors

Factors that increase the risk of impetigo include:

  • Age. Impetigo most commonly occurs in children ages 2 to 5.
  • Crowded conditions. Impetigo spreads easily in schools and child care settings.
  • Warm, humid weather. Impetigo infections are more common in summer.
  • Certain sports. Participation in sports that involve skin-to-skin contact, such as football or wrestling, increases your risk of developing impetigo.
  • Broken skin. The bacteria that cause impetigo often enter your skin through a small skin injury, insect bite or rash.

Adults and people with diabetes or a weakened immune system are more likely to develop ecthyma.

Complications

Impetigo typically isn't dangerous. And the sores in mild forms of the infection generally heal without scarring.

Rarely, complications of impetigo include:

  • Cellulitis. This potentially serious infection affects the tissues underlying your skin and eventually may spread to your lymph nodes and bloodstream. Untreated cellulitis can quickly become life-threatening.
  • Kidney problems. One of the types of bacteria that cause impetigo can also damage your kidneys.
  • Scarring. The ulcers associated with ecthyma can leave scars.