Impetigo

Impetigo is a contagious, superficial skin infection. Impetigo may cause a blistering area on the skin or, more commonly, an itchy, crusted, weeping sore that may grow larger and spread.


Causes/associated factors
Impetigo is a bacterial infection caused by streptococci (strep), staphylococci (staph) or both. However, Staphylococcus aureus causes the majority of impetigo infections. The condition mainly affects children, but it can happen at any age.

Transmission
Impetigo spreads easily through contact with drainage from the sores. This can happen by touching a sore or sharing towels, washcloths or clothing with someone who has impetigo. It can also spread through autoinoculation, which occurs when someone who has impetigo spreads the disease to other places on his or her own body by touching the sores and then touching another body part. The infection is most common during the summer, when you're more likely to have insect bites, cuts and scratches. These openings in the skin allow bacteria to enter your skin and cause infection more easily.
After exposure, it can take 10 to 20 days for the sores to develop. You're considered contagious until the sores have stopped draining.

You're more likely to develop impetigo if you:

have dermatitis (inflammation of the skin) or another skin disorder
have a condition that weakens your immune system (such as cancer)
have a poor diet or are malnourished
live or work in a warm, humid environment
live in crowded conditions
have poor personal hygiene
currently have chickenpox, scabies or lice
live with someone who has impetigo

Signs/symptoms
Impetigo typically begins as small, red sores on the face. You may notice sores on your lips or near your nose and mouth. You may develop sores on other parts of your body as well. The sores quickly become small blisters, which eventually weep and develop golden yellow crusts. The sores don't usually hurt, but they may burn or itch. Underneath the crusts, your skin may be red or raw.

Diagnosis
Diagnosis is typically based on the appearance of the sores. Your doctor may ask if you've been exposed to anyone with impetigo. Impetigo can appear similar to certain viral skin infections such as the herpes simplex virus (HSV) or shingles varicella-zoster virus (VZV), so lab tests on the fluid from the sores may be needed to verify the type of organism.

Treatment
The doctor may prescribe oral antibiotics or recommend a topical antibacterial ointment, such as bacitracin or the prescription ointment mupirocin (Bactroban, for example). The condition typically clears up within a week to 10 days.
At one time, erythromycin was the oral antibiotic of choice for treating impetigo. The bacteria that causes impetigo is becoming more resistant to this medication, however, so your doctor may prescribe other antibiotics such as dicloxacillin, cephalexin or azithromycin. If your doctor prescribes oral antibiotics, you may need to take the medication for seven to 10 days (unless prescribed azithromycin, which is taken for five days). Remember to take all of the medication, even when the sores begin to look better.

If your doctor recommends an ointment, you'll need to remove the scabs from the sores first so that the medication can reach the bacteria. To remove the scabs, gently wash or soak the infected areas with warm water and an antibacterial soap, such as Lever 2000 or Hibiclens. The sores will look raw, and they may even bleed a little. Try to avoid removing any new thin crusting -- it's part of the healing process. Wear a glove or use a sterile cotton swab to apply the ointment, and wash your hands afterward. To prevent spreading the infection, cover the sores with bandages until they stop draining. You may need to apply the ointment several times a day or as often as your doctor recommends.

If itching is severe, your doctor may recommend an over-the-counter antihistamine such as diphenhydramine (Benadryl, for example) or loratidine (Claritin, for example).


Complications
In up to 5 percent of cases, usually in children, impetigo caused by a certain type of strep bacteria can lead to a serious kidney condition called poststreptococcal glomerulonephritis. This condition, which may appear about two to four weeks after the impetigo, can cause blood in the urine, swelling, high blood pressure and kidney damage. Children typically recover completely from glomerulonephritis, but adults are more prone to permanent kidney damage. Other rare complications include infections in the joints, bones, lungs, the deeper layers of skin or the bloodstream.
Consult your doctor if:

You develop a fever or sore throat.
Red streaks come from the sores.
The sores or blisters are an inch in diameter or larger.
The sores spread.
The sores don't improve after 48 hours of treatment. In this case, lab analysis of the drainage may be needed.
Your urine becomes red or cola-colored.
Your eyelids are swollen (this is a sign of glomerulonephritis or an allergic reaction).
Other people in your family or household develop impetigo and require treatment.

Pregnancy-specific information
Pregnancy doesn't increase the risk of developing impetigo. If you've been exposed to impetigo, consult your doctor. Treatments may differ from those recommended for other adults.

Senior-specific information
Although impetigo is most common in children, it can spread to older adults. Because older adults are more likely to have conditions that affect the immune system, such as diabetes or cancer, they're at greater risk for impetigo. If you suspect you may have impetigo, contact your doctor.

Prevention
Consider the following suggestions to prevent impetigo:
Practice proper hygiene. Wash your hands often, especially after changing a diaper or using the toilet.
Keep your children's fingernails trimmed and clean.
Give each member of the family his or her own washcloth and towel.
Don't share bath water, towels, bedding or clothes with an infected person.
If the infected person lives in your household, clean the bathtub after each use. Wash the person's towels, bedding and clothing every day.
Disinfect any toys an infected child may have used.
Avoid anyone who may be contagious.
If you have a minor skin injury or insect bite, wash the affected area with soap and water and apply an over-the-counter triple antibiotic ointment (Neosporin, for example).
Seek treatment for dermatitis or other associated health conditions.