What is impetigo?
Impetigo is a superficial skin infection characterized by a honey-crusted rash or large blisters (called bullae) at the site of previous irritation. The initial irritation could be a rub, scratch, scrape, cut, insect bite, cracking from dryness, eczema patch or any other breakdown in the skin barrier. Often the patient does not recall a particular irritation to the skin prior to impetigo developing.
What causes impetigo?
Impetigo occurs when bacteria find a way under the surface of the skin. Most cases of impetigo are caused by strains of Streptococcus (strep for short) and Staphylococcus (staph for short). These are bacteria that live on the surface of our skin all the time and are just waiting for an opportunity to move to a more ideal moist and warm location (underneath vs. on top of the skin), where they can survive longer.
Staph? You mean MRSA?
MRSA, or methicillin-resistant Staphylococcus aureus, is just one strain of bacteria that can cause impetigo. As the name suggests, MRSA is resistant to some of the more common antibiotics we prescribe for bacterial infections, but good treatments are available such as clindamycin and sulfamethoxazole-trimethoprim (commonly known as Bactrim). Other strains of staph can also cause impetigo, and remain sensitive to treatment with penicillins and cephalexin (also known as Keflex).
Is any testing required to diagnose or treat impetigo?
No, typically the diagnosis is made by observation of the rash. However, sometimes culturing the lesion can be helpful in determining which bacteria is causing the rash, and the antibiotics to which that bacteria is sensitive and/or resistant. Culture results don’t typically return for several days, so treatment is typically started while awaiting those results. If there is not a high risk of MRSA exposure (e.g., known exposure at home or school, contact sports and sports with shared equipment/mats such as gymnastics, wrestling, football, etc), a narrow-spectrum antibiotic is started. If the rash does not improve within 2-3 days on this treatment, the antibiotic is switched or a second antibiotic is added to broaden coverage against MRSA as well.
Who can get impetigo?
Anyone of any age can get impetigo. It is more common in those at risk for skin irritation or skin breakdown such as those with eczema, or who suck on fingers, bite nails, or pick at their skin. It is also more common in those who participate in sports that are contact-based or require shared equipment that frequently contacts the skin.
How is impetigo treated?
As noted above, the treatment choice depends on the extent of the rash and the risk for MRSA exposure. If the rash is a single, isolated lesion we may start with a prescription-strength antibiotic ointment called mupirocin. If the rash is scattered over the body we are more likely to prescribe an oral antibiotic. As with all bacterial infections (e.g., strep throat, ear infections, UTIs, and skin infections such as impetigo) we always try to prescribe the most narrow-spectrum antibiotic that we believe will be effective for a given infection. This is important for lowering the likelihood of developing antibiotic resistance. Patients are also encouraged to clean the infected area with soap and water at least once per day.
Is impetigo contagious?
Yes, it is contagious. To avoid the spread of impetigo we recommend:
- Good hand hygiene practices for the infected individual and close contacts
- Starting appropriate treatment promptly upon seeing the rash
- Keeping a crusted, oozing or draining rash covered by adhesive bandages and/or clothing until they scab and are healing
- Avoiding shared towels, bed linens, clothes, razors or other objects that may come in contact with the infected skin
- Keep laundry of the infected individual separate and wash on hot cycle
- Clean commonly touched surfaces such as door knobs, handles, and countertops
- Staying home from school or daycare until on appropriate antibiotic treatment for at least 24 hours
If I see honey-crusted spots on my child, will PAR call in a prescription for us?
No, an office visit is required for evaluation of impetigo. Other rashes such as poison ivy and viral infections such as cold sores can mimic impetigo. In order to make the right diagnosis and get your child on the correct treatment we need to evaluate your child in person.
If my child has impetigo and participates in sports, when can they return?
Per VHSL guidelines, return to contact practices and competition may occur after:
- 72 hours of appropriate antibiotic treatment (PAR NOTE: for return to play, some schools/sports may require oral antibiotics vs. antibiotic ointment only. Prior to your visit, please check with your child’s coach to see if there are any such requirements)
- All lesions have a well-adherent scab without any drainage or weeping fluids
- No new lesions have developed in the preceding 48 hours
Is there anything I should look out for or call PAR about after my child is started on treatment?
Please call us if your child has impetigo and:
- Your child develops a temperature of 100.4oF (38oC) or higher
- The rash does not improve within 2-3 days of starting treatment, or is worsening despite initial treatment
- There is swelling, pain or warmth to touch around the rash
- Your child begins to look or act unwell