Impetigo is caused by streptococcus (strep) or staphylococcus (staph) bacteria. Methicillin-resistant staph aureus (MRSA) is becoming a common cause.
Skin normally has many types of bacteria on it. When there is a break in the skin, bacteria can enter the body and grow there. This causes inflammation and infection. Breaks in the skin may occur from injury or trauma to the skin or from insect, animal, or human bites.
Impetigo may also occur on skin where there is no visible break.
Impetigo is most common in children who live in unhealthy conditions.
In adults, it may occur following another skin problem. It may also develop after a cold or other virus.
Impetigo can spread to others. You can catch the infection from someone who has it if the fluid that oozes from their skin blisters touches an open area on your skin.
Symptoms of impetigo are:
One or many blisters that are filled with pus and easy to pop. In infants, the skin is reddish or raw-looking where a blister has broken.
Blisters that itch, are filled with yellow or honey-colored fluid, and ooze and crust over
Rash that may begin as a single spot, but spreads to other areas with scratching
Skin sores on the face, lips, arms, or legs that spread to other areas
Swollen lymph nodes near the infection
Patches of impetigo on the body (in children)
Exams and Tests
Your health care provider will look at your skin to determine if you have impetigo.
Your provider may take a sample of bacteria from your skin to grow in the lab.This can help determine if MRSA is the cause. Specific antibiotics are needed to treat this type of bacteria.
The goal of treatment is to get rid of the infection and relieve your symptoms.
Your health care provider will prescribe an antibacterial cream. You may need to take antibiotics by mouth if the infection is severe.
Gently wash (do not scrub) your skin several times a day with an antibacterial soap to remove crusts and drainage.
The sores of impetigo heal slowly. Scars are rare. The cure rate is very high, but the problem often comes back in young children.
Impetigo may lead to:
Spread of the infection to other parts of the body (common)
Impetigo. Alvero R, Ferri FF, Fort GG, et al, eds. In: Ferri's Clinical Advisor 2015. 1st ed. Philadelphia, PA: Elsevier Mosby; 2014:section I.
Morelli JG. Cutaneous Bacterial Infections. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 657.
Pasternack MS, Swartz MN. Cellulitis, necrotizing fasciitis, and subcutaneous tissue infections. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2009:chap 90.
Richard J. Moskowitz, MD, dermatologist in private practice, Mineola, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.