Impetigo

Impetigo is a common, highly contagious skin infection caused by bacteria. It mainly affects the top layers of the skin. Anyone can get it, although it is seen most often in young children.

The infection usually begins as red sores or fragile blisters. These break open and leave moist patches with a yellow or golden-brown crust. The crust is sometimes described as looking like honey.

Impetigo often develops around the nose and mouth, but it can appear anywhere. It may spread to nearby skin through scratching or to other people through close contact and shared items.

Most cases are mild and clear with appropriate treatment. Treatment also helps reduce the chance of spreading the infection or developing complications. Because other skin conditions can look similar, a healthcare professional may need to examine the affected skin.

The most common type is non-bullous impetigo. It usually starts as small red spots or blisters. These quickly break and form moist sores covered by honey-coloured crusts. The sores may be itchy or mildly uncomfortable, but severe pain is not typical.

Common sites include:

• Around the nose and mouth
• The hands, arms, or legs
• Areas of scratched, irritated, or injured skin
• Skin affected by eczema, insect bites, or scabies

Bullous impetigo causes larger, fluid-filled blisters. “Bullous” means blistering. The blisters have thin roofs, so they may break easily and leave red, shiny areas. This type is more likely to affect the trunk, diaper area, or skin folds. It is caused by toxins released by certain strains of Staphylococcus aureus bacteria.

A deeper form called ecthyma causes painful sores that extend below the upper skin layer. The sores may have thick crusts with ulcers underneath. Ecthyma is more likely to leave scars and needs medical treatment.

Some people have swollen lymph nodes near the infection. Fever or feeling generally unwell is less common and may suggest that the infection is more extensive or spreading.

Impetigo is usually caused by Staphylococcus aureus, group A Streptococcus, or both. These bacteria can live on the skin or in the nose without causing symptoms. Infection can begin when they enter damaged or irritated skin.

The bacteria spread through direct contact with infected skin or fluid from the sores. They can also spread through items that have touched the affected area, such as towels, clothing, bedding, toys, or sports equipment.

Factors that make impetigo more likely include:

• Close contact with someone who has the infection
• Warm, humid conditions
• Crowded living or childcare settings
• Contact sports involving skin-to-skin contact
• Cuts, grazes, insect bites, or scratched skin
• Eczema, scabies, or other itchy skin conditions
• Difficulty keeping affected skin clean and covered
• A weakened immune system or poorly controlled diabetes

Impetigo is not a sign of poor personal hygiene. However, handwashing and careful cleaning can help limit its spread once it appears.

Impetigo is usually diagnosed by examining the skin. The pattern of sores, blisters, and honey-coloured crusts is often enough to identify it.

Testing is not always needed. A healthcare professional may take a swab from a blister, sore, or crust if the infection is not improving, keeps returning, or appears to be spreading through a household or group. The sample can be tested to identify the bacteria and determine which antibiotics like amoxicillin or doxycycline are likely to work.

Other conditions can resemble impetigo. These include cold sores, contact dermatitis, eczema, fungal skin infections, chickenpox, shingles, and infected insect bites. An examination helps separate these conditions.

Blood tests and scans are not routinely used for straightforward impetigo. They may be considered if there are signs of a deeper or more serious infection.

Treatment depends on how much skin is affected, whether there are blisters, and whether the infection has spread more deeply.

A limited area of non-bullous impetigo may be treated with a topical antiseptic or antibiotic applied to the skin. Recommendations differ by location because bacterial resistance and available products are not the same everywhere.

An oral antibiotic may be used when there are many sores, large blisters, ecthyma, widespread infection, or signs that infection is spreading. It may also be chosen during an outbreak affecting several people. Treatment should be taken or applied exactly as directed and completed unless a healthcare professional advises otherwise.

Gentle skin care can make the area more comfortable and reduce spread. Wash affected skin carefully with soap and water, then pat it dry. Softening crusts with warm water may make them easier to clean, but avoid forceful scrubbing or picking.

Keep sores covered with a clean, light dressing when practical. Wash your hands before and after touching the area or applying treatment. Do not share towels, washcloths, razors, clothing, bedding, cosmetics, or skin products.

Avoid using leftover antibiotics or another person’s medicine. Over-the-counter antibiotic creams are not suitable in every case and may cause skin reactions or contribute to antibiotic resistance.

The infection often starts improving within a few days of effective treatment. Seek follow-up if sores are still spreading, new blisters continue to appear, or there is no clear improvement after the period advised by the treating healthcare professional. A swab or a different treatment may be needed.

Complications are uncommon, especially when impetigo is recognised and treated.

The infection can sometimes spread into deeper skin, causing cellulitis. This produces expanding redness, warmth, swelling, and tenderness. An abscess, which is a pocket of pus, may also develop.

Ecthyma can damage deeper layers of skin and may leave scars. Ordinary superficial impetigo usually heals without scarring, although temporary lighter or darker skin marks can remain after the sores clear.

Rarely, infection with certain streptococcal bacteria is followed by kidney inflammation called post-streptococcal glomerulonephritis. Possible signs include dark or reddish urine, swelling around the eyes or ankles, and passing less urine than usual. Antibiotic treatment controls the skin infection but does not reliably prevent this uncommon kidney complication.

Extensive blistering, peeling skin, or significant illness can indicate a more serious toxin-related infection, particularly in babies and young children. This needs urgent assessment.

Impetigo cannot always be prevented because the bacteria that cause it may already live harmlessly on the skin or in the nose. You can reduce the risk of infection and limit its spread.

Clean cuts, grazes, and insect bites promptly. Try not to scratch itchy skin, and seek treatment for conditions such as eczema or scabies when they are not controlled.

If someone has impetigo, regular handwashing is important. Keep their fingernails short and discourage picking at sores. Cover affected areas when possible, especially around other people.

Wash used towels, bedding, and clothing regularly, and do not share personal items. Clean commonly touched surfaces and washable toys during a household outbreak.

Rules for returning to school, childcare, work, swimming, or contact sports differ by location. People are generally less contagious after effective antibiotics have been used for the required period and exposed sores can be covered. Follow the advice given with treatment and any local public health or school policy.

With effective treatment, impetigo usually begins to settle within a few days and heals over about one to two weeks. The crusts loosen, redness fades, and new sores stop appearing. Healing can take longer when a large area is affected or when there is ecthyma.

The affected skin may look pink, lighter, or darker after the infection has cleared. These colour changes often fade gradually over weeks or months. Superficial impetigo does not usually cause permanent skin damage.

Impetigo can return. This is more likely when eczema, scabies, frequent scratching, or another source of broken skin continues. Repeated infections may also occur when bacteria remain in the nose or spread between close contacts. A healthcare professional may use swabs or recommend a specific plan for recurrent cases rather than repeatedly using the same treatment.

Most people return to their usual activities once they are no longer considered contagious and the sores can be safely covered. Impetigo does not normally cause ongoing health problems or long-term limits on daily life.

Arrange a routine or prompt medical assessment if you think you or your child may have impetigo. Early advice is particularly useful when the affected person is a baby, has a weakened immune system, has diabetes, or has widespread eczema.

Seek same-day medical advice if:

• Redness, swelling, warmth, or pain is spreading
• There is fever or the person feels increasingly unwell
• Sores are close to the eyes
• Large blisters or deep ulcers develop
• Treatment is not working as expected
• The condition repeatedly returns
• Dark urine, reduced urination, or facial or ankle swelling develops

Get emergency help for rapidly worsening illness, confusion, difficulty waking, trouble breathing, extensive skin peeling, or rapidly spreading redness with severe pain. These are not usual features of uncomplicated impetigo.

Is impetigo contagious?

Yes. It spreads through contact with infected skin, blister fluid, or contaminated personal items. Careful handwashing, covering sores, and not sharing towels or clothing can reduce spread.

How long is impetigo contagious?

Contagiousness falls after effective treatment begins, but the exact exclusion period used by schools, childcare settings, workplaces, and sports organisations differs. Follow the instructions provided with treatment and local rules. Without treatment, it can remain contagious while sores are active.

Can adults get impetigo?

Yes. It is more common in children, but adults can develop it, particularly after skin injury, during close-contact sports, or when eczema or another skin condition weakens the skin barrier.

Can I go swimming with impetigo?

Swimming is usually avoided while sores are open, leaking, or cannot be securely covered. Shared changing areas and close contact may spread bacteria. Return according to medical advice and the pool’s policy.

Will impetigo go away by itself?

Some limited cases may eventually clear, but treatment can shorten the infection and reduce transmission and complications. It is best to have suspected impetigo assessed rather than relying on it to resolve without care.

Does impetigo leave scars?

Superficial impetigo usually does not scar. Temporary changes in skin colour can remain after healing. The deeper form, ecthyma, is more likely to cause permanent scars.