Impetigo
A contagious superficial bacterial skin infection, common in young children, that causes blisters or honey-colored crusted sores.
What causes Impetigo?
Impetigo is caused by Staphylococcus aureus, Streptococcus pyogenes, or both. Bacteria enter through small skin breaks and spread by direct contact with sores, drainage, contaminated hands, clothing, towels, or linens.
Symptoms and what to notice
Non-bullous impetigo begins with red spots or small blisters that rupture and form golden honey-colored crusts. Bullous impetigo produces larger fragile blisters. Itching is common; pain and fever are usually limited unless infection spreads.
How long can it last?
Group A strep impetigo has an incubation period around 10 days. With appropriate antibiotics, lesions often improve within a few days and heal over one to two weeks. Untreated infection can persist and spread.
How serious is Impetigo?
Complications are uncommon but include cellulitis, abscess, scarring after deeper infection, kidney inflammation after streptococcal disease, and rarely invasive infection. New evidence suggests rheumatic fever can occasionally follow group A strep skin infection.
Treatment and management
A few lesions are commonly treated with topical mupirocin or retapamulin; numerous lesions or outbreaks may require oral antibiotics active against both strep and staph. Local resistance, MRSA risk, allergy, and severity guide selection.
Vaccine: who and when?
No FDA-approved vaccine prevents impetigo, group A strep infection, or Staphylococcus aureus infection. Prevention relies on skin care, hygiene, covering lesions, and timely antibiotic treatment.
Cost note: No vaccine price applies. Examination, culture when needed, and antibiotic costs vary by medication, provider, insurance, and local resistance patterns.
Trusted source
Patient cost varies by insurance, provider, location, and eligibility. Coverage and public-health access differ, so listed prices are examples rather than guaranteed patient prices. This page is for general education and does not replace individualized medical advice, diagnosis, vaccination assessment, or treatment.
Impetigo: Symptoms, Causes, Treatment, Prevention, and Vaccine Information
Impetigo affects the outer layers of skin and is especially common among children ages two through five. Warm weather, crowding, eczema, insect bites, scabies, and minor cuts make infection easier. The classic honey-colored crust is recognizable, but other conditions can look similar. Treatment speeds healing, reduces transmission, and may lower the risk of complications.
Important: This page is for general education. It does not replace diagnosis, treatment, vaccination advice, or emergency care from a qualified healthcare professional.
Quick Facts
| Topic | Current information |
|---|---|
| Cause | Impetigo is caused by Staphylococcus aureus, Streptococcus pyogenes, or both. Bacteria enter through small skin breaks and spread by direct contact with sores, drainage, contaminated hands, clothing, towels, or linens. |
| Main symptoms | Non-bullous impetigo begins with red spots or small blisters that rupture and form golden honey-colored crusts. Bullous impetigo produces larger fragile blisters. Itching is common; pain and fever are usually limited unless infection spreads. |
| Typical course | Group A strep impetigo has an incubation period around 10 days. With appropriate antibiotics, lesions often improve within a few days and heal over one to two weeks. Untreated infection can persist and spread. |
| Treatment | A few lesions are commonly treated with topical mupirocin or retapamulin; numerous lesions or outbreaks may require oral antibiotics active against both strep and staph. Local resistance, MRSA risk, allergy, and severity guide selection. |
| Vaccine status | No FDA-approved vaccine prevents impetigo, group A strep infection, or Staphylococcus aureus infection. Prevention relies on skin care, hygiene, covering lesions, and timely antibiotic treatment. |
History and Public-Health Importance
Impetigo has long been recognized as a contagious childhood skin disease. Modern microbiology established two main bacterial causes: group A Streptococcus and Staphylococcus aureus. Antibiotic resistance, particularly methicillin-resistant S. aureus in some communities, makes clinical judgment and local resistance patterns important. Public-health guidance emphasizes hygiene, lesion coverage, and appropriate—not excessive—antibiotic use.
What Causes Impetigo?
Impetigo is caused by Staphylococcus aureus, Streptococcus pyogenes, or both. Bacteria enter through small skin breaks and spread by direct contact with sores, drainage, contaminated hands, clothing, towels, or linens.
Bacteria move through direct skin contact or drainage from a lesion and may spread on towels, clothing, bedding, sports equipment, or scratching fingers. Nasal carriage of S. aureus can contribute to recurrent episodes. Impetigo is more likely when the skin barrier is disrupted by dermatitis, bites, cuts, burns, or scabies. Pets are not considered the primary source of human group A strep.
Symptoms and Typical Course
Non-bullous impetigo begins with red spots or small blisters that rupture and form golden honey-colored crusts. Bullous impetigo produces larger fragile blisters. Itching is common; pain and fever are usually limited unless infection spreads.
Non-bullous lesions progress from papules to pustules and then thick adherent crusts, usually on the face or limbs. Bullous disease, caused by toxin-producing S. aureus, creates larger fluid-filled blisters. Most patients otherwise feel well. Rapidly expanding redness, severe pain, fever, or systemic symptoms suggest deeper infection and require reassessment.
Complications and Who Is at Higher Risk
Complications are uncommon but include cellulitis, abscess, scarring after deeper infection, kidney inflammation after streptococcal disease, and rarely invasive infection. New evidence suggests rheumatic fever can occasionally follow group A strep skin infection.
Cellulitis and abscess can develop when infection extends below the superficial skin. Post-streptococcal glomerulonephritis can appear one to two weeks later with dark urine, swelling, or high blood pressure. Invasive infection is rare but more concerning in newborns, immunocompromised people, or patients with extensive bullous disease.
How It Is Diagnosed
Clinicians usually diagnose impetigo by appearance. Examination cannot reliably determine whether strep, staph, or both are present. Culture of pus or drainage may help when disease is recurrent, widespread, severe, associated with an outbreak, or not responding to expected therapy. Other possibilities include herpes, contact dermatitis, scabies, fungal infection, and eczema.
Treatment and Recovery
A few lesions are commonly treated with topical mupirocin or retapamulin; numerous lesions or outbreaks may require oral antibiotics active against both strep and staph. Local resistance, MRSA risk, allergy, and severity guide selection.
Topical antibiotics are effective for limited disease after gentle cleansing and removal of loose crusts. Oral therapy is preferred for many lesions, bullous disease, outbreaks, or deeper infection. Patients should complete the prescribed course and avoid sharing medication. Recurrent disease may prompt assessment for nasal carriage, household transmission, eczema, or other skin-barrier problems.
Vaccine Information
No FDA-approved vaccine prevents impetigo, group A strep infection, or Staphylococcus aureus infection. Prevention relies on skin care, hygiene, covering lesions, and timely antibiotic treatment.
No licensed vaccine targets the two principal causes. Group A strep and S. aureus vaccine research continues, but no candidate is approved for routine use. Antibiotic ointments are treatments, not vaccines, and they should not be used repeatedly without medical guidance because resistance and skin reactions can occur.
Prevention
Wash hands, keep nails short, clean minor wounds, avoid scratching, cover draining lesions, and do not share towels, razors, clothing, or bedding. Machine-wash items used by an infected person daily during active disease. Children can generally return to school or childcare when well and at least 12 hours after effective antibiotics, with lesions covered; local rules may be stricter.
When to Seek Medical Care
Seek care when lesions spread quickly, involve the eyes, cause significant pain or fever, recur often, affect a newborn, or fail to improve. Urgent evaluation is needed for rapidly spreading redness, red streaks, severe swelling, lethargy, or breathing problems.
Frequently Asked Questions
Is impetigo contagious?
Yes. It spreads through contact with lesions or contaminated hands and personal items. Antibiotics and lesion coverage reduce spread.
What causes the honey-colored crust?
Superficial blisters rupture and their fluid dries into the characteristic golden crust.
Can impetigo heal without treatment?
Some cases eventually resolve, but treatment shortens illness, limits transmission, and reduces complications.
Is there an impetigo vaccine?
No. Neither a group A strep nor a Staphylococcus aureus vaccine is currently licensed.
Key Takeaway
Impetigo is usually straightforward to treat but highly contagious. Early appropriate antibiotics, clean covered lesions, and household hygiene help stop spread and prevent deeper infection.
Medical, treatment, and vaccine information was reviewed against official U.S. public-health guidance available through September 2026.