Impetigo: Honey-Crusted Skin Infection

What impetigo looks like

Impetigo has two main forms.

Non-bullous impetigo (honey-crusted impetigo)

About 70% of cases are this type. It starts as a small red spot or tiny blister that bursts within hours, leaving a moist, red area that oozes. The fluid dries into the classic honey-colored or golden-brown crust, sometimes described as looking like cornflakes stuck to the skin. Sores:

• usually appear around the nose and mouth, on the face, hands and forearms
• spread by scratching, so new sores appear nearby ("satellite" lesions)
• can be itchy but are rarely painful
• may come with swollen glands in the neck
• heal without scarring, sometimes leaving temporary red or pale marks

Bullous impetigo

This form is caused by toxin-producing Staph aureus. It forms larger, fluid-filled blisters (bullae), 1 to 2 cm or more, that stay intact for a few days before bursting and leaving a thin, yellow-brown crust and a raw rim. It is more common in babies and young children and affects the trunk, armpits, nappy area, arms and legs. Children with bullous impetigo are more likely to have fever and feel unwell.

Ecthyma

Ecthyma is a deeper form that eats through the skin into the dermis. It causes painful punched-out ulcers with thick, dark crusts, usually on the legs, and can leave scars. It needs antibiotic tablets.

What causes impetigo?

Two bacteria cause impetigo:

• Staphylococcus aureus: the most common cause in the US and Europe, including MRSA in some areas
• Streptococcus pyogenes (group A strep): more common in hot, humid climates

Many healthy people carry staph in the nose. The bacteria get into the skin through small breaks:

• insect bites, cuts and grazes
• scratched eczema (atopic dermatitis), scabies or head lice
• cold sores and chickenpox spots
• a runny nose that irritates the skin under the nostrils

Impetigo on otherwise healthy skin is called primary impetigo. Impetigo on skin already damaged by another condition is secondary impetigo or impetiginization.

Risk factors

• age 2 to 5
• warm, humid weather (it peaks in summer)
• crowded settings: daycare, schools, military barracks
• contact sports such as wrestling
• eczema and other itchy skin conditions
• diabetes and weakened immunity in adults

Is impetigo contagious?

Yes, very. It spreads by direct contact with sores and the fluid from them, and by sharing towels, clothes, bedding, razors and toys. You can also spread it to other parts of your own body by scratching. The incubation period is usually 4 to 10 days after exposure.

You are contagious:

• until 48 hours after starting antibiotic treatment, or
• until all sores have dried and crusted over if you do not have treatment, which can take 2 to 3 weeks

How impetigo is diagnosed

A doctor, nurse or pharmacist usually recognizes impetigo by looking at the sores. A swab for culture is taken if:

• sores are not clearing with treatment
• impetigo keeps coming back
• MRSA is suspected
• there is a possible link to an outbreak

Recurrent impetigo may prompt a nose swab to check whether you or family members carry staph.

Conditions that look similar

Treatment of honey-crusted impetigo

Treatment shortens how long you are contagious and speeds healing. Mild impetigo can clear on its own in 2 to 3 weeks, but treatment is usually recommended.

Localized impetigo (a few sores)

• Hydrogen peroxide 1% cream is recommended first in UK guidance (NICE) for people who are not systemically unwell.
• Topical antibiotic ointment such as mupirocin, fusidic acid or retapamulin, applied 2 to 3 times a day for 5 days, is used in the US and when peroxide is unsuitable. Over-the-counter triple antibiotic ointments are less effective.
• Before applying, gently soak crusts with warm soapy water and pat them dry. You do not have to scrub crusts off.

Widespread, bullous or severe impetigo

Oral antibiotics, usually for 5 to 7 days, are used for many sores, bullous impetigo, ecthyma, fever, or when creams fail. Common choices are cephalexin or flucloxacillin (dicloxacillin in the US). Doctors choose alternatives for penicillin allergy or MRSA.

Home care during treatment

• Wash hands after touching sores or applying cream.
• Cover sores loosely with gauze where possible.
• Keep fingernails short to reduce scratching.
• Use separate towels and wash them, with bedding and clothes, at 60 °C (140 °F).
• Keep children off school or daycare until 48 hours after antibiotics start, or until sores have crusted if untreated.

Recurrent impetigo

If impetigo keeps returning, doctors may treat staph carriage with an antibiotic ointment in the nostrils for several days, and recommend antiseptic body washes. Treating underlying eczema well also cuts recurrences.

Complications of impetigo

Complications are uncommon:

• Cellulitis: deeper spread causing hot, red, painful swelling
• Scarring: mainly after ecthyma or scratching
• Post-streptococcal glomerulonephritis: kidney inflammation 1 to 3 weeks after strep impetigo, with dark urine, swelling and high blood pressure. Antibiotics do not prevent it.
• Staphylococcal scalded skin syndrome: toxin-driven widespread peeling in babies and young children
• Scarlet fever, sepsis and guttate psoriasis: rare

Preventing impetigo

• Clean cuts, scrapes and bites with soap and water.
• Treat eczema and itchy conditions so skin is not broken by scratching.
• Do not share towels, razors or sports equipment.
• Wash hands regularly, especially in daycare settings.

Frequently asked questions

What are honey-crusted lesions in impetigo?

They are the dried fluid from burst sores. The liquid that oozes from impetigo sores dries into a golden or honey-colored crust that looks like dried honey or cornflakes on the skin. This appearance is typical of non-bullous impetigo caused by staph or strep.

What is the treatment for honey-crusted lesions?

Small areas are treated with hydrogen peroxide 1% cream or an antibiotic ointment such as mupirocin for about 5 days, after gently soaking off loose crusts. Widespread sores, blisters or fever need oral antibiotics. Hand washing and covering sores help stop spread.

How long is impetigo contagious?

Impetigo is contagious until 48 hours after starting antibiotic treatment. Without treatment it stays contagious until all the sores have crusted and healed, which can take 2 to 3 weeks.

Can adults get impetigo?

Yes. Adults catch it from children, through contact sports or after skin damage such as eczema, cold sores or shaving cuts. Adults with diabetes or weak immunity are more prone to it and to deeper forms such as ecthyma.

Does impetigo leave scars?

Usually not, because it is a surface infection. Healed areas may stay red or pale for weeks before fading. Deep ecthyma and heavy scratching can leave scars.

Can impetigo go away on its own?

Mild impetigo often clears without treatment in about 2 to 3 weeks. Treatment is still recommended, because it shortens the illness, stops spread to others and lowers the risk of complications.