What Is Impetigo?

Impetigo is a highly contagious bacterial skin infection that causes sores and a honey-colored crust or blister-like bumps. It can be itchy and painful, and it occurs when skin—especially already irritated or broken skin—comes in contact with a common type of staph or the bacteria responsible for strep throat.

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Types and Symptoms of Impetigo

Impetigo can happen to anyone, but it typically affects infants and children and is most common in those ages 2 to 5. Those diagnosed with impetigo are usually treated with topical antibiotics or oral antibiotics to avoid complications and prevent its spread.

There are three types of impetigo that are classified based on the appearance of the infected skin and how deep the infection goes into skin layers.

Though there are some common areas where impetigo begins, untreated infections can quickly spread to other areas on the child's body. Pain and itchiness may occur in all types of impetigo, and scratching can further spread the infection.

Nonbullous Impetigo (Impetigo Contagiosa)

The most common form of impetigo, it involves only the outermost layers of skin called the epidermis. It often occurs in areas where the skin has been broken, irritated, or damaged.

The nostrils, especially in kids with runny noses, are commonly affected. The face, the neck, and the hands are other areas of the body where you are likely to see lesions.

Key features:

• It begins as red, itchy sores that drain clear fluid or pus for a few days.
• Honey-colored, crusted lesions then develop over the sores.

Bullous Impetigo

Bullous impetigo also affects the epidermis. It tends to form in areas where skin folds or rubs against other skin, including the arms, legs, trunk, buttocks, armpits, and groin.

Key features:

• It begins with fluid-filled blisters.
• Lesions are much larger and may stay intact on the skin longer before rupturing.
• Lesions may ooze a yellow fluid.

Ecthyma (Deep Impetigo)

This is a more serious bacterial infection that goes into the deeper skin layer of the dermis.

Key features:

• It begins as a pustule; blisters are painful.
• Blisters turn into deep punched-out ulcers; a brown-black crust may also form.

When to See a Healthcare Provider

If you notice any itchy or painful red bumps, a honey-colored crust over sores, or blister-looking bumps on your child's skin, call the pediatrician immediately so that it can be treated and to prevent it from spreading elsewhere on the child or to others.

Causes

Impetigo can occur when skin is exposed to either:

• Staphylococcus aureus, a type of staph responsible for a variety of types of skin infections and other concerns
• Group A Streptococcus (GAS or Group A strep, also known as Streptococcus pyogenes), also responsible for strep throat, cellulitis, and other infections

The likely culprit(s) of a case of impetigo ultimately depends on the type that occurs.

Ecthyma can occur from untreated impetigo that develops into a deeper infection.

Impetigo can develop as a primary infection when the bacteria infects normal skin, or it can form as a secondary infection when bacteria invades already irritated or open skin, such as from a wound, insect bite, poison ivy, eczema, herpes, or scabies.

Direct contact with infected lesions is what causes spread. This can occur in a number of ways and settings, such as:

• When a child scratches an infected area and then touches another part of their body
• Hugs, hand-shaking, or other forms of direct contact with an infected individual
• Engaging in certain sports, such as wrestling
• Crowded areas, such as schools or daycare centers

Though technically one step removed from direct contact, the infection can also spread if you touch the clothes, towels, or sheets of an infected person.

The bacteria that lead to impetigo thrive in hot and humid environments and infections are more common in tropical or subtropical climates.

Diagnosis

Diagnosis of impetigo is usually made after a practitioner examines the skin and notices the typical appearance of the infection.

A healthcare provider may also want to do a bacterial culture if they suspect that impetigo is being caused by a resistant bacteria, such as MRSA (methicillin-resistant staphylococcus aureus), or if a rash is not going away.

Treatment

For small areas of infection, an over-the-counter or prescription-strength topical antibiotic is typically all that is needed. You will also need to regularly wash the area with warm, soapy water and then cover it with a bandage to prevent spread to others.

For more extensive or persistent infections, an oral or intravenous antibiotic might be needed. Ecthyma is typically treated with oral antibiotics, for example.

MRSA is resistant to many of the antibiotics that are commonly used to treat impetigo, including Keflex (cephalexin), Augmentin (amoxicillin, clavulanic acid), Zithromax (azithromycin), and cefdinir. If MRSA is the cause of the infection, a stronger antibiotic, such as Cleocin (clindamycin) or Bactrim (sulfamethoxazole, trimethoprim), may be needed.

Once treatment starts, the infection should begin to disappear within a few days. If you aren't noticing a change, let your healthcare provider know since a different medication may be needed.

Repeat Infections

It is possible to get impetigo more than once. If impetigo or other staph-related skin infections continue to occur, your practitioner may recommend that all members of your household get treated with antibiotics, such as Bactroban (mupirocin) nasal gel twice a day for five to seven days.

Other measures, such as baths with Hibiclens (an antiseptic, antimicrobial skin cleanser) and very frequent hand washing, may also be recommended.

Prognosis

Most cases of impetigo resolve without complications or scarring. If a scar does occur, it is typically from a deep infection of ecthyma. In these cases, you may want to see a dermatologist who can offer treatments to minimize the appearance of the scar.

In extremely rare cases, impetigo can lead to serious complications if it goes untreated. These can include:

• Post-streptococcal glomerulonephritis, inflammation of the filters of the kidneys that can develop after a Group A strep infection. This can lead to hematuria (bloody urine) and high blood pressure.
• Scarlet fever, a condition caused by Group A strep that is characterized by fever, rash, and a red tongue
• Septicemia, a serious blood infection caused by bacteria

A Word From Verywell

As with most infections, one of the best preventative steps you can take to reduce your risk of impetigo or prevent an existing infection from spreading is to wash your hands frequently and for at least 20 seconds each time.

Make sure children follow good hand hygiene, and if they have any bites, scrapes, or rashes, keep a close eye on them and keep them clean and covered.