What causes impetigo?

The skin normally acts as a barrier. A scratch, cut, insect bite, burn, chafing, or itchy rash can create an opening for bacteria. Rubbing and scratching can move bacteria from one area to another. Children and adults can both develop impetigo, and close contact makes transfer easier.

An underlying skin problem such as Atopic Dermatitis may leave the barrier dry, inflamed, or scratched. That does not mean every flare is infected. Crusting, oozing, increasing tenderness, or new sores can prompt an assessment; see Crusting Skin for a related symptom explanation.

Clean small breaks in the skin, avoid picking, and keep fingernails short. Do not share towels, face cloths, clothing, bedding, razors, or cosmetics while sores are active. Wash hands after touching the area and launder fabrics that contact lesions. If a clinician diagnoses impetigo, use the recommended treatment exactly as directed. Treatment information is available under Topical Antibiotic Therapy and Antibiotics For Skin Infection.

Seek medical advice for spreading sores, repeated episodes, infection near the eye, or a rash that is difficult to distinguish from eczema or another condition. Prompt review is needed for fever, rapidly increasing redness, warmth, swelling, pain, pus, or a person who seems unwell. Do not wait for a cause to become obvious if symptoms are changing quickly.

Ask what may have broken the skin barrier, whether an underlying rash needs treatment, how to prevent household spread, and which medicine is appropriate for the extent and location of the sores.