Impetigo is a common and highly contagious bacterial skin infection. It is seen most often in young children, especially between the ages of 2 and 5, but older children and adults can develop it as well.
The infection usually affects the surface of the skin and often appears around the nose and mouth or on the arms and legs. One of its most recognizable signs is a sore that breaks open and develops a golden or honey-colored crust.
Although impetigo can look concerning, most cases are treatable and do not cause serious complications. Because the infection spreads easily from person to person, recognizing and treating it promptly can also help protect family members, classmates, and others who may be in close contact.
Impetigo is caused by bacteria, most commonly Staphylococcus aureus (often called “staph”) and group A Streptococcus (often called “strep”). Sometimes both types of bacteria are involved.
These bacteria can enter the skin through small breaks in its protective surface. The opening may be so minor that it is barely noticeable.
Common ways the skin barrier can become damaged include:
Impetigo can also develop on skin that appears normal, so an obvious injury is not always present.
Impetigo usually develops on exposed areas of the skin, particularly around the nose and mouth and on the arms or legs. The infection may begin in one small area and then spread to nearby skin.
There are two main forms of impetigo: nonbullous impetigo and bullous impetigo.
Nonbullous impetigo is the most common form. It often begins as small red bumps or tiny blisters that quickly develop into pustules or sores.
The sores eventually break open, release fluid, and form a characteristic yellow, golden, or honey-colored crust. Several lesions may appear close together, especially when scratching spreads bacteria to surrounding skin.
Classic Sign: A superficial sore with a honey-colored crust, particularly around a child’s nose or mouth, is a classic appearance of nonbullous impetigo.
Bullous impetigo is less common. It is usually caused by certain strains of Staphylococcus aureus that produce toxins that cause the upper layers of the skin to separate.
Instead of developing mainly crusted sores, people with bullous impetigo develop larger, fragile, fluid-filled blisters called bullae. The fluid may initially appear clear and later become cloudy or darker.
The blisters eventually rupture, leaving shallow raw areas of skin that may develop a thin crust.
| Nonbullous Impetigo | Bullous Impetigo |
|---|---|
| More common | Less common |
| Often begins as small bumps, blisters, or pustules | Produces larger fluid-filled blisters |
| Typically develops honey-colored crusts | Blisters rupture and leave shallow raw areas |
| Can be caused by staph, strep, or both | Usually caused by toxin-producing S. aureus |
Yes. Impetigo is very contagious. The bacteria can spread through direct contact with an infected person’s sores or through objects that have been contaminated by fluid from the lesions.
For example, infection may spread through shared towels, washcloths, clothing, bedding, or other personal items. Children can also spread the infection to other parts of their own bodies by touching or scratching a lesion and then touching another area of skin.
This is one reason impetigo can spread relatively quickly through households, schools, sports teams, and child-care environments.
Most people with uncomplicated impetigo do not feel seriously ill. The infection usually remains limited to the skin.
Some people may develop swollen lymph nodes near the affected area, and less commonly symptoms such as fever or weakness may occur.
A high fever, rapidly spreading redness, significant swelling, increasing pain, or feeling generally very unwell is not typical of a simple localized case and should prompt medical evaluation.
Healthcare professionals can usually diagnose impetigo by examining the skin. Its appearance and location are often distinctive enough that laboratory testing is unnecessary.
In certain situations, a sample from the affected area may be sent for bacterial testing. This may be considered when the infection is not improving with treatment, keeps returning, occurs during an outbreak, or when an antibiotic-resistant bacterium such as MRSA is suspected.
Treatment depends largely on how widespread the infection is and which type of impetigo is present.
For a small number of localized nonbullous lesions, a healthcare professional may prescribe a topical antibiotic that is applied directly to the affected skin.
If there are many lesions, large areas are involved, bullous impetigo is present, or topical treatment is not appropriate or has not worked, an oral antibiotic may be necessary.
The specific antibiotic should be selected by a healthcare professional based on the likely bacteria, the extent of infection, allergies, local antibiotic-resistance patterns, and culture results when testing has been performed.
Important: Do not use leftover antibiotics or another person’s prescription to treat a suspected case of impetigo. Not every skin infection requires the same antibiotic, and some bacteria may be resistant to particular medications.
MRSA stands for methicillin-resistant Staphylococcus aureus. It is a type of staph bacterium that is resistant to several commonly used antibiotics.
Most cases of impetigo are not automatically assumed to be MRSA. However, resistant bacteria may be considered when an infection does not respond as expected, repeatedly returns, or when other risk factors are present. A bacterial culture can help determine which antibiotics are likely to work when resistance is a concern.
Medical treatment should be combined with basic skin care and measures that reduce the chance of spreading bacteria.
Because impetigo spreads easily through close contact, children may need to remain home temporarily after treatment begins.
The exact return-to-school or day-care requirement can vary depending on local public health recommendations and institutional policies. Parents should follow the advice of their child’s healthcare professional and the policies of the school or child-care center.
Good hand hygiene and avoiding direct contact with active lesions remain important even after a child returns.
Most cases of impetigo clear without lasting problems when appropriately managed. However, complications can occasionally occur.
Sometimes the infection extends deeper into the skin and produces ecthyma, a deeper form of bacterial skin infection that can cause ulcers rather than superficial crusted sores.
Other complications are uncommon, but worsening symptoms should not be ignored—particularly when redness begins spreading beyond the original lesions or the person becomes systemically unwell.
Because several skin conditions can resemble impetigo, medical evaluation is helpful when a new crusting, blistering, or draining rash develops—particularly in a young child.
Seek medical attention promptly if you notice:
The best prevention strategy is to reduce opportunities for bacteria to spread and to protect the skin from unnecessary damage.
Impetigo is a contagious bacterial infection of the outer layers of the skin that occurs most often in young children. The most common form produces superficial sores that rupture and develop characteristic honey-colored crusts, while bullous impetigo causes larger fluid-filled blisters.
Most cases respond well to appropriate treatment. Small, localized infections may be treated with a topical antibiotic, while more widespread or bullous infections may require oral antibiotics. Good hygiene, avoiding scratching, and not sharing personal items are equally important for preventing the infection from spreading.
Remember: Honey-colored crusted sores are a classic clue for impetigo, but not every blistering or crusted rash is impetigo. If a rash is spreading, painful, associated with fever, or not improving, it should be evaluated by a healthcare professional.
Bolaji RS, Dabade TS, Gustafson CJ, Davis SA, Krowchuk DP, Feldman SR. Treatment of impetigo: oral antibiotics most commonly prescribed. J Drugs Dermatol. 2012;11(4):489–494.
Gilbert DN, Chambers HF, Eliopoulos GM, Saag MS, Pavia AT. The Sanford Guide to Antimicrobial Therapy. 50th ed. Sperryville, VA: Antimicrobial Therapy, Inc.; 2020.
Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):e10–e52.
